Short-term functions and long-term consequences of body checking as a transdiagnostic phenomenon across eating disorders, body dysmorphic disorder, and illness anxiety disorder: a systematic review

Abstract

Body checking refers to the repeated evaluation of one’s own body. As a safety mechanism, it is prevalent in various mental disorders, including eating disorders, body dysmorphic disorder, and illness anxiety disorder. While the type and manner of body checking behavior may differ between these disorders, cognitive-behavioral models highlight similar mechanisms underlying this behavior. According to the models, body checking is assumed to arise in response to negative affect, offer immediate relief, and increase psychopathology in the longer term as a mechanism of negative reinforcement. The objective of this review is to empirically evaluate these assumptions for eating disorders, body dysmorphic disorder, and illness anxiety disorder. Therefore, we conducted a systematic literature review across four electronic databases, with N = 43 studies meeting the inclusion criteria. The assumption that body checking occurs in response to negative affect was supported. However, findings regarding its short- and long-term role in maintaining negative affect were inconsistent. Therefore, our results may suggest the need to re-evaluate the etiologically proposed negative reinforcement mechanism of body checking in eating disorders, body dysmorphic disorder, and illness anxiety disorder. To facilitate the interpretation of study findings, future studies should distinguish between short- and long-term effects of body checking.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40337-025-01462-0.

Plain language summary

Body checking refers to the repeated and critical evaluation of one’s body and contributes to the maintenance of eating disorders, body dysmorphic disorder, and illness anxiety disorder. While individuals with these disorders engage in disorder-specific checking behaviors, the cognitive-behavioral theories underlying these behaviors are similar. These theories propose that body checking arises in response to negative affect, provides short-term relief, and increases negative affect in the long term. The present literature review aims to empirically assess these theoretical assumptions across eating disorders, body dysmorphic disorder, and illness anxiety disorder, including N = 43 studies meeting the inclusion criteria. The findings support the notion that body checking occurs in situations characterized by negative affect and contributes to increased negative affect in the long term. However, evidence regarding the short-term role of checking behavior in reducing negative affect was inconsistent, challenging the theoretical assumption of immediate relief. Our results suggest reevaluating the proposed short-term reduction in negative affect, indicating that checking behavior may not provide an immediate reduction of negative affect as previously assumed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40337-025-01462-0.

Background

Checking behavior refers to the repeated and critical evaluation for example of one’s body, and is a common behavior among individuals with eating disorders, body dysmorphic disorder, and illness anxiety disorder. This systematic literature review aims to evaluate the empirical evidence supporting the cognitive-behavioral theories of checking behavior in eating disorders, body dysmorphic disorder, and illness anxiety disorder. According to the theories, checking behavior is hypothesized to: (1) occur in situations characterized by negative affect, (2) reduce this negative affect in the short term, and (3) lead to an increase in negative affect and disorder-specific psychopathology in the longer term. The N = 43 studies included in our PRISMA-guided search provide evidence that checking behavior occurs in contexts marked by negative affect. Moreover, most studies support the theory that checking behavior contributes to increased negative affect over time. However, findings regarding the theoretically proposed short-term reduction of negative affect through checking behavior were inconsistent.

The vast majority of people engage in some form of checking behavior, such as double-checking one’s alarm clock before a crucial meeting or ensuring that travel documents are packed before a trip [1]. Compulsive checking, however, is a transdiagnostic phenomenon that is observed in clinical populations [2] and is regarded as a safety behavior, along with avoidance. As such, checking behavior can be defined as “actions taken to prevent, avoid, or escape a feared outcome” [3, p. 71], and it is assumed that these behaviors are tailored to individual core concerns and fears [4]. From a phenomenological perspective, checking behavior was initially explored in the realm of obsessive-compulsive disorder [5, 6] and then transferred to other disorders such as eating disorders [7], body dysmorphic disorder [8, 9], or illness anxiety disorder [10, 11]. However, there are important conceptual differences between body checking and compulsive checking. While checking behavior in obsessive-compulsive disorder predominantly involves control over objects and the environment, in other disorders, such as eating disorders [7], body dysmorphic disorder [8, 9], or illness anxiety disorder [10, 11], checking behavior is less evolving around objects but refers to the critical and repeated evaluation of one’s own body. While this phenomenon, known as body checking, is present across various disorders, its specific nature varies depending on the specific disorder. Although body-related checking can also occur in obsessive-compulsive disorder, for example, checking the body for physiological signs of arousal in response to feared thoughts [12], this behavior usually serves as a safety response to an external threat. By comparison, in eating disorders, body dysmorphic disorder, and illness anxiety disorder, the body itself is the feared stimulus such as fears of being too fat [13], flawed [14] or ill [15], making body checking in these disorders more directly rooted in distorted body image.

In eating disorders, specifically anorexia nervosa, bulimia nervosa, and binge eating disorder, body checking is characterized by efforts to exert control over one’s body by gathering information about weight, shape, or body fat percentage [16]. This behavior is evident in actions such as repeated weighing, visually inspecting one’s body or specific body parts in mirrors or other reflective surfaces, measuring the circumference of body parts, checking the fit of clothes and jewelry, touching or pinching body parts, touching bones, seeking reassurance from others, or making comparisons with others’ bodies [7]. The abdomen and thighs are often focal points for these checking behaviors, as these areas are commonly associated with weight gain [17].

Individuals with body dysmorphic disorder likewise engage in body checking but focus on specific body parts they perceive as flawed, such as the skin, hair, nose, eyes, and, particularly for men, body build and genitals [8]. Body checking takes the form of examining these specific body parts in mirrors or other reflective surfaces, touching them to monitor their condition, seeking reassurance from others about one’s appearance, or mentally comparing one’s own appearance, especially the perceived flaw, with that of others [9].

In eating disorders and body dysmorphic disorder, the primary concerns, and consequently the resulting body checking behaviors, center on one’s appearance. In the case of illness anxiety disorder, by contrast, body checking serves the purpose of scrutinizing the body for signs of illness or seeking reassurance about health and the interpretation of bodily sensations from various sources (e.g., family and friends, healthcare professionals; 10). The specific form of body checking undertaken depends on the feared disease. For example, it may involve repeated visual inspection of birthmarks as potential indicators of skin cancer, eye tests to rule out brain tumors or neurological diseases, measuring blood pressure or pulse due to concerns about cardiovascular diseases, or examining the female breasts for potential indicators of breast cancer [11].

Even though body checking pertains to different domains (e.g., shape, flaws, illness) and manifests differently depending on the specific disorder, the postulates of etiological cognitive-behavioral models show considerable similarities regarding the mechanism of body checking. Three theoretical predictions are consistently posited across the theoretical frameworks of eating disorders, body dysmorphic disorder and illness anxiety disorder: First, it is theorized in all three cognitive-behavioral models that body checking occurs in situations characterized by unpleasant emotional states [18–20]. Second, it is postulated that body checking serves to reduce this unpleasant emotional state in the short term [18–20] (e.g., eating disorders: [20]; body dysmorphic disorder: [18]; illness anxiety disorder: [19]). This temporary emotion regulation effect to alleviate negative affect is believed to lead to negative reinforcement, as individuals perceive the behavior as helpful and necessary for coping with unpleasant emotions, consequently increasing the likelihood of future body checking [18–20]. The third postulate, by contrast, suggests that repeated body checking contributes to long-term negative affect, and thus acts a self-perpetuating mechanism that sustains psychopathology [18–20]. Such sustaining factors are thought to include biases in memory and selective attention (e.g [16, 21]).

The model assumptions are illustrated here using eating disorders as an example: In accordance with the aforementioned considerations, the theoretical models propose that body checking serves to establish a sense of self-control and to alleviate body-related negative affect in the short term. This negative affect may be triggered, for instance, by dysfunctional body-related information processing or heightened concerns about potential weight gain [16, 20]. The reduction of negative affect reinforces not only the behavior itself but also the belief in the necessity of engaging in repeated body checking. Emotional reasoning, such as “I feel anxious, so it must be harmful,” contributes to the perpetuation of eating-disordered beliefs (e.g., fear of gaining weight, worry about weight and shape) in the long term [20]. Additionally, Fairburn et al. [16] proposed that consistent and frequent body checking leads to biased information processing. When the body is repeatedly inspected in a state of heightened arousal, the perception of imperfections in one’s appearance becomes intensified. This, in turn, heightens anxiety, arousal, and self-focused attention, triggering more checking and setting a detrimental cycle in motion. Moreover, the perception of self-control diminishes, necessitating an intensification of eating-disordered behavior (e.g., restricted eating, vomiting) in order to regain a sense of control [16].

Altogether, body checking is universally conceptualized, across different disorders, as a safety behavior, and is seen within cognitive-behavioral models as playing a pivotal role in providing an essential emotion regulation mechanism. While these theoretical assumptions for body checking [18–20] are widely accepted and form the foundation for various therapeutic techniques, such as exposure and ritual prevention therapy (i.e., refraining from using body checking to demonstrate that situations can be mastered without safety behaviors; [22]), the evidence base has not yet been systematically assessed. Therefore, the objective of this paper is to comprehensively examine the empirical evidence concerning the three theoretical postulates related to body checking from a transdiagnostic perspective. To examine body checking transdiagnostically may be useful, as all three disorder models are based on the same rationale: a short-term reduction of negative affect accompanied by its long-term maintenance [18–20]. However, findings from individual studies on body checking have been inconsistent with regard to the proposed reinforcement mechanisms both within and across disorders, for example in eating disorders [7] and body dysmorphic disorder [23]. This suggests that discrepancies may exist between theoretical assumptions and empirical evidence.

Clinically, a transdiagnostic analysis of the short-, and long-term consequences of body checking may be valuable for refining existing therapeutic manuals for eating disorders [24], body dysmorphic disorder [25], and illness anxiety disorder [26]. The rationale underlying these disorders assumes that body checking behavior is maintained through negative reinforcement mechanisms. Accordingly, cognitive-behavioral treatment rationales propose that patients should reduce or limit body checking in order to prevent the perpetuation of negative affect and the disorder itself (cf. 24, 25, 26). However, if the assumption of short-term symptom reduction through body checking does not hold, or does not apply equally across disorders, this would potentially alter the therapeutic implications.

To achieve these objectives, we present and summarize the existing empirical evidence regarding body checking and its alignment with the three theoretical postulates for eating disorders, body dysmorphic disorder, and illness anxiety disorder. In order to consider the dimensional perspective of psychological constructs (e.g., body dissatisfaction, health anxiety), we additionally integrate evidence from individuals without a mental disorder diagnosis into this synthesis. To examine potential differences between clinical and non-clinical samples, we conducted an exploratory analysis. Specifically, we addressed the following three research questions: (1) Is body checking predominantly performed in an aversive (emotional) state?; (2) Does body checking reduce aversive emotional, cognitive, and disorder-specific outcomes in the short term?; and (3) Does body checking contribute to an amplification and perpetuation of aversive emotional, cognitive, and disorder-specific outcomes in the long term?

Methods

We adhered to recent methodological recommendations for systematic reviews and formulated a protocol following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [27]. The protocol was registered with PROSPERO under the registration number CRD42021238835. A brief overview of our methods is provided here, and more detailed information is available in the published protocol [28]. It is important to note that, deviating from the protocol, this paper specifically addresses the effects of body-related checking behavior. The screening and synthesis of results pertaining to obsessive-compulsive disorder and generalized anxiety disorder are still pending.

Selection criteria and outcomes

For inclusion, primary studies needed to investigate the impact of body checking in adult populations, including either clinical or non-clinical populations. The studies could have various different designs (e.g., randomized controlled trials, pre-post uncontrolled studies without a comparison group) and settings (e.g., laboratory, field, questionnaires). Studies were excluded if they examined checking behavior that was not specific to and representative of the respective disorder (e.g., interpersonal checking in eating disorders, i.e., asking loved ones if they are upset). Additionally, studies that primarily focused on therapeutic confrontation with one’s appearance (e.g., exposure intervention with a clear therapeutic rationale) were also excluded. We were interested in both disorder-specific (e.g., body dissatisfaction) and more global measures (e.g., anxiety). To be considered in the review, studies had to assess changes in at least one emotional or cognitive measure. To ensure a clear categorization of studies into their respective research questions and simultaneously consider the aforementioned model assumptions, we defined effects that occurred in the context of a single body checking episode as short-term effects and defined the consequences of repeated use of body checking as long-term effects.

Search strategy

In the initial phase, we formulated search strings (cf. supplementary material) using keywords, including the “Thesaurus of Psychological Index Terms,” and free-text words, combined with Boolean operators. Our search specifically targeted studies with terms related to “checking” in the title or abstract, and we applied a filter to include only studies involving human participants. The electronic databases PsycINFO, PubMed, PSYNDEX, and Scopus were systematically screened, and we further examined the references of selected publications and research registries (e.g., ClinicalTrials.gov) to identify additional studies. Following the removal of duplicate records, two independent reviewers conducted an initial assessment based on titles and abstracts. Subsequently, the full texts of potentially suitable studies were scrutinized according to the predefined inclusion and exclusion criteria.

Data extraction

Data extraction was carried out independently by one reviewer and cross-verified by a second reviewer. We utilized a data collection form that underwent pilot testing in a multistage process. The extracted data encompassed fundamental study characteristics, such as title, authors, and publication year. Additionally, information about the sample, including size, gender distribution, and average age, as well as details about the setting (e.g., online survey, laboratory experiment), were collected. The form also included a description of the investigated body checking, assessment time points, outcomes, and study results in relation to the research questions.

Given the diversity of study settings (e.g., laboratory, field study, questionnaires) and designs (e.g., assessment time points, type of checking behavior, and measured outcomes), coupled with the limited number of suitable studies, conducting a meta-analysis was not feasible. Consequently, we opted for a narrative synthesis of the results to effectively capture and present the findings.

Risk of bias

In a departure from our published protocol, we opted to utilize a tool specifically designed to assess the quality of quantitative studies. The quality assessment tool from the Effective Public Health Practice Project (EPHPP) was employed to evaluate the risk of bias, considering various study designs. This tool has been shown to be effective in assessing study quality across a range of research contexts (e.g., [29, 30, 31]). One reviewer categorized each area as strong (1 point), moderate (2 points), or weak (3 points). To arrive at an overall score, the values for each area were examined and categorized by following the recommendations (i.e., strong = no weak ratings, moderate = one weak rating, weak = two or more weak ratings). To visually present the results, we employed the generic Robvis tool [32].

Results

Study characteristics

The study selection process is visually depicted in Fig. 1. We included studies up to April 2025. During the screening phase, records were excluded if the reported data did not meet basic plausibility criteria e.g., inconsistencies between sample size and statistical analyses, incomplete outcome reporting, or missing essential study information such as diagnostic criteria (cf. Flow chart). The initial electronic search yielded 3510 records. Following the removal of duplicates (n = 1,87), a total of 1,723 studies underwent title screening. After excluding 1426 records, 297 records underwent abstract screening. The full texts of 219 articles were requested and scrutinized. Of these, 181 records were excluded because they did not meet our predefined eligibility criteria (e.g., wrong study population, intervention not focused on body checking, not empirical research, or publication type such as reviews, commentaries, or dissertations); thus, a total of 38 manuscripts were included and analyzed. Between completion of the literature search and submission of the present manuscript, six further studies were included in the narrative synthesis. Thus, the final review comprised 43 studies. Table 1 presents the characteristics of the 43 selected studies, categorized by the examined disorder, with three studies being transdiagnostic and exploring multiple diseases. Four studies were reported outside of this schema as they did not specifically investigate checking behavior and instead focused on the reduction of appearance-related behaviors in general. Additionally, a total of four publications referenced an identical dataset (i.e., two in each case), which was noted accordingly. In total, we obtained 26 records on eating disorders, 14 on body dysmorphic disorder, and six on illness anxiety disorder, all addressing at least one of the pertinent research questions (cf. Table 1). The studies were published between 1999 and April 2025. This time frame was chosen because the first cognitive-behavioral treatment manuals addressing body checking and related behaviors were published around that period, and the number and quality of earlier studies were generally insufficient to meet our inclusion criteria. Earlier publications were therefore unlikely to rely on comparable theoretical frameworks or diagnostic criteria, and were excluded to ensure consistency and clinical relevance of the reviewed evidence.

Fig. 1.

Flow chart showing the study selection process

Table 1.

Overview of the study demographics included in the synthesis

Study ID	Author, publication year	Sample characteristics	Study design	Checking behavior	Outcomes	Research question
	Eating disorders
01	Bailey & Waller (2017)	- Non-clinical: N = 50 - 100% female	- Naturalistic setting, cross-over study - Experimental conditions: (1) checking every 15 min for 1 day; (2) no checking	- Checking wrist size	- Body satisfaction - ED pathology	3
02	Blechert et al. (2009)	- BN: n = 20 - non-clinical: n = 22 - 100% female	- Laboratory experiment, eye-tracking - Looking at a picture of one’s own body and of persons with higher/lower BMI	- Looking at pictures, comparing	- Body satisfaction	2
03	Calugi et al. (2017)	- AN: n = 66 - Non-clinical: n = 182 - 100% female	- Treatment study (inpatient enhanced CBT) - Assessment at admission, end of treatment and 6- and 12-month follow-up	- Assessed with the Body Checking Questionnaire (BCQ)	- ED pathology - Psychopathology	3
04	Engel et al. (2013)	- AN: N = 118 - 100% female	- EMA - Signal-contingent measurement (six random times per day) - Event-contingent measurement (any AN behavior or eating episode) - Interval-contingent measurement (at the end of each day)	- Weighing	- Negative affect - Positive affect	2
05	Farrel et al. (2019)	- ED: N = 71 - 92% female	- Treatment study (exposure-based)	- Assessed with the Body Checking Questionnaire (BCQ)	- ED pathology	3
06	Geiger et al. (in press)	- High weight concern: n = 103 - Low weight concern: n = 76 - 100% female	- Naturalistic setting, cross-over study - Experimental conditions: (1) 3-fold increased BC over 3 days; (2) usual BC over 3 days	- ED-related BC (not further specified)	- Positive and negative affect - ED pathology - Body dissatisfaction - Depressive feelings	3
07	Guthoff et al. (2019)	- High weight concern: n = 63 - Low weight concern: n = 62 - 100% female	- Online survey - Assessment before, during, immediately after, and 15 min after remembered BC episodes of liked/disliked body parts	- Mirror, assume certain position, pinching/ touching, comparing, measuring	- Negative affect (i.e., arousal, valence)	2
08	Goeden et al. (2023)	- Full or partial AN: N = 118 - 100% female-	- EMA - Measurement: signal-contingent to assess BC; - Interval-contingent to assess dietary restriction - Event-contingent to assess eating episodes or AN behaviors	- Make sure thighs are not touching, check joints and bones for fat, weighing	- ED pathology (exercise, laxative use, skipping meals, fluid intake, vomiting)	3
09	Hartmann, Cordes et al. (2019)	- AN: n = 50 - BN: n = 46 - 98% female	- Online survey - Baseline measurement - Assessment immediately before, during, and immediately after, 15 min after, and 60 min after remembered BC episode	- n.r.	- Negative affect (i.e. arousal, valence, anxiety, worry)	1 2
10	Kostopoulou et al. (2013)	- BN: n = 20 - AN: n = 11 - 100% female	- Laboratory experiment - Elicit thought-shape fusion and reduce effects through safety behaviors	- Checking behavior - Mental neutralization	- Negative affect (i.e. anxiety, guilt, feelings of fatness)	2
11	Kraus et al. (2015)	- ED: n = 26 - CG: n = 29 - 100% female	- EMA - Time-contingent measurement (“right now”) - Event-contingent measurement (pre-post BC)	- All ED-typical behaviors (i.e., mirror, weighing, measuring, touching, comparing etc.)	- Negative affect - Positive affect	1 2
12	Lavender et al. (2013)	- Full or partial AN: N = 118 - 100% female	- EMA - Measurement: signal-contingent to assess BC; interval-contingent to assess dietary restriction	- Two strategies: make sure thighs are not touching, check joints and bones for fat	- Dietary restriction	3
13	Opladen et al. (2022)	- Non-clinical: N = 167 - 100% female	- Naturalistic setting, cross-over study - Experimental conditions: (1) 3-fold increased BC over 3 days; (2) usual BC over 3 days	- ED-related BC (not further specified)	- Negative affect - ED pathology - Anxiety - Depressive feelings	3
14	Hofschröer et al. (accepted)	- Non-clinical - N = 102 - 100% female	- Laboratory experiment - Cross-over design, experimental conditions: (1) BC task; (2) checking vase - Induction of negative affect pre checking behavior	- ED-, BDD- or IAD-related BC instructions	- Negative affect - Arousal - Disorder-specific psychopathology	2
15	Hofschröer et al. (submitted)	- n = 108 clinical (BN, BDD or IAD) - n = 116 non-clinical - 90% female	- Laboratory experiment - Cross-over design, experimental conditions: (1) BC task; (2) checking vase - Induction of negative affect pre checking behavior	- Disorder-specific BC instructions	- Negative affect - Arousal - Disorder-specific psychopathology - Psychophysiology	2
16	Pak et al. (2018)	- AN: N = 82 - 100% female	- EMA - Signal-contingent, interval-contingent (end of day) and event-contingent measurement	- Two strategies: make sure thighs are not touching, check joints and bones for fat	- Negative affect	1 2
17	Pellizzer et al. (2018)	- ED: N = 78 - 92% female	- Data from case series (CBT) - Assessment at baseline, mid- and post-treatment, 1- and 3-month follow-up	- Assessed with the Body Checking Questionnaire (BCQ)	- ED pathology	3
18	Pellizzer et al. (2019)	- ED: N = 62 - 92% female	- Treatment study (CBT) - Assessment at baseline, end of treatment, and 3-month follow-up	- Assessed with the Body Checking Questionnaire (BCQ)	- ED pathology - Clinical impairment	3
19	Sala et al. (2019)	- ED: N = 66 - 97% female	- EMA - Signal-contingent measurement over 1 week - 1-month follow-up assessing ED pathology	- Weighing, body checking (not further specified)	- ED pathology	3
20	Shafran et al. (1999)	- high TSF scores: N = 30 - 87% female	- Laboratory experiment - Elicit thought-shape fusion and reduce effects through safety behaviors	- Mirror checking - Other safety behaviors like mental neutralization	- Negative affect (i.e., anxiety, guilt, feelings of fatness)	2
21	Shafran et al. (2007)	- Non-clinical: N = 60 - 100% female	- Laboratory experiment - Experimental conditions: (1) critical body checking; (2) neutral body checking - Assessment before, immediately after, and 30 min after BC	- Checking disliked body parts or inspecting the body as a whole in a neutral way	- Body dissatisfaction - Estimation of body size	2
22	Stefano et al. (2016)	- Non-clinical with high body concerns: N = 22 - 100% female	- EMA - Signal-contingent measurement over 5 days	- Weighing, feeling thighs for fatness, sucking/pinching stomach, comparing, mirror, fat jiggling, thighs spread while sitting	- Body dissatisfaction - Negative affect	3
23	Tanck et al. (2019)	- Non-clinical - Women: n = 60 - Men: n = 60	- Laboratory experiment, crossover design - Gender differences - Experimental conditions: (1) positive checking; (2) negative checking; (3) control – computer game	- Standardized instructions to check negatively/positively valenced body parts	- Body satisfaction - Guilt	2
24	Walker et al. (2021)	- Non-clinical with high shape and weight concerns: N = 74 - 100% female	- Laboratory experiment - Experimental conditions: (1) critical body checking; (2) neutral body checking; (3) non-body critical checking - Assessment before, directly after, and 1 week after BC	- Checking disliked body parts or inspecting the body as a whole in a neutral way	- Body satisfaction - Self-esteem - Negative affect	2
25	Wilhelm et al. (2020)	- High weight and shape concerns: n = 179 - Low weight and shape concerns: n = 176 - 100% female	- Online survey - Assessment before, during, immediately, and 15 min after remembered BC episode of liked/disliked body parts	- Pinching, measuring, comparing, asking for feedback, mirror, specific position, weighing	- Negative affect (arousal, valence)	2
26	Wilson et al. (2020)	- BN: n = 41 - Non-clinical, n = 43 - 100% female	- Laboratory experiment - BC of the least liked body part	- Mirror, examine from different angles, touch it and/or sit in a chair	- Perceptual confidence - Body satisfaction	2
	Body dysmorphic disorder
27	Barnier & Collison (2019)	- Non-clinical: N = 55 - 78% female	- Laboratory experiment - Experimental conditions: (1) low self-focused attention, (2) high self-focused attention	- Mirror: asked to look in the mirror from a distance of 100 cm vs. focus on a part of face or disliked body part from 10 cm	- Body satisfaction - Feelings of attractiveness - Distress - Urge to change appearance - Shame - Self-esteem	2
28	Chuah & Suendermann (2024)	- Non-clinical - Women: n = 35 - Men: n = 28	- Laboratory experiment - Experimental conditions: (1) low self-focused attention, (2) high self-focused attention-	- Mirror: asked to look in the mirror from a distance of 100 cm vs. focus on a part of face or disliked body part from 10 cm	- Appearance satisfaction (overall and facial) - Perceived attractiveness - Distress - Urge to gaze - Vividness and emotional quality of imagery	2
29	Cordes et al. (2017)	- Non-clinical, N = 49 - 100% male, weight-training	- Laboratory experiment, eye-tracking - Experimental conditions, looking at pictures: (1) self; (2) normal; (3) muscular; (4) hyper-muscular	- Looking at pictures, comparing	- Body satisfaction - Negative affect	2
09	Hartmann, Cordes et al. (2019)	- BDD: N = 35 - 69% female	- Online survey - Baseline measurement - Assessment immediately before, during, and immediately after, 15 min after, and 60 min after remembered BC episode	- n.r.	- Negative affect (i.e. arousal, valence, anxiety, worry)	1 2
31	Möllmann et al. (2020)	- Non-clinical: N = 115 - 100% female	- Laboratory experiment - Manipulation of: (a) face: (1) photographed face of a stranger; (2) own photographed face; (3) own face in the mirror; (b) gazing duration: 0, 7.5, 15, 30 and 300s	- Gazing at faces	- Dissociation - Feelings of attractiveness - Uncertainty of perception	2
32	Mulkens & Jansen (2009)	- Non-clinical: N = 50 - Subgroups: high (n = 16) vs. low (n = 16) satisfaction - 100% female	- Laboratory experiment - Experimental conditions: (1) own face in mirror; (2) photograph of a strange face	- Mirror, comparing	- Feelings of attractiveness	2
33	Oakes et al. (2017)	- BDD: N = 8 - 63% female	- Semi-structured interview	- Asking about body related behaviors	- n.r.	2
14	Hofschröer et al. (accepted)	- non-clinical - N = 102 - 100% female-	- Laboratory experiment - Cross-over design, experimental conditions: (1) BC task; (2) checking vase - Induction of negative affect pre checking behavior-	- ED-, BDD-, or IAD-related BC instructions	- Negative affect - Arousal - Disorder-specific psychopathology	2
15	Hofschröer et al. (submitted)	- n = 108 clinical (BN, BDD or IAD) - n = 116 non-clinical - 90% female	- Laboratory experiment - Cross-over design, experimental conditions: (1) BC task; (2) checking vase - Induction of negative affect pre checking behavior-	- Disorder-specific BC instructions	- Negative affect - Arousal - Disorder-specific psychopathology - Psychophysiology	2
34	Veale et al. (2016)	- non-clinical: N = 173 - 100% female	- Laboratory experiment, mirror gazing - Experimental conditions: (1) external focus of attention; (2) self-focus of attention; (3) self-focus of attention with negative mood induction	- Mirror gazing	- Dissatisfaction with appearance - Sadness	2
35	Veale & Riley (2001)	- BDD: n = 52 - Non-clinical: n = 55 - 56% female	- Questionnaire - Retrospective assessment before and immediately after looking in the mirror	- Mirror checking	- Distress - Depressive feelings	1 2
36	Walker et al. (2012)	- Non-clinical: N = 234 - 100% male	- Laboratory experiment - Experimental conditions: (1) critical body checking; (2) neutral body checking	- Checking disliked body parts or inspecting the body as a whole in a neutral way	- Body satisfaction - Muscle dissatisfaction	2
37	Windheim et al. (2011)	- BDD: n = 25 - Non-clinical: n = 25 - 48% female	- Laboratory experiment, mirror gazing - Short vs. long sessions	- Mirror gazing	- Distress	2
	Illness anxiety disorder
38	Abramowitz & Moore (2007)	- IAD: N = 27 - 78% female	- Laboratory experiment, exposure to an idiosyncratic illness trigger - Experimental conditions: (1) safety behavior; (2) response prevention	- All types of safety behavior (reassurance seeking, google, checking, medication)	- Anxiety - Urge to complete safety behavior	2
39	Doherty-Torstrick et al. (2016)	- Non-clinical: N = 720 - 66% female	- Online survey, recall of searching on the internet for information about symptoms - Assessment during and after remembered internet search	- Reassurance seeking	- Anxiety	2
09	Hartmann, Cordes et al. (2019)	- IAD: N = 45 - 84% female	- Online survey - Baseline measurement - Assessment immediately before, during, and immediately after, 15 min after, and 60 min after remembered BC episode	- n.r.	- Negative affect (i.e. arousal, valence, anxiety, worry)	1 2
40	Olatunji et al. (2011)	- Non-clinical: N = 60 - 77% female	- Naturalistic setting - Experimental conditions: (1) A/B/A, A = normal frequency of health behaviors; B = increase health behaviors for 1 week; (2) AAA	- Safety behavior checklist	- Health anxiety - Hypochondriacal beliefs - Behavioral avoidance - Anxiety	3
13	Hofschröer et al. (accepted)	- Non-clinical - N = 102 - 100% female-	- Laboratory experiment - Cross-over design, experimental conditions: (1) BC task; (2) checking vase - Induction of negative affect pre checking behavior-	- ED-, BDD-, or IAD-related BC instructions	- Negative affect - Arousal - Disorder-specific psychopathology	2
14	Hofschröer et al. (submitted)	- n = 108 clinical (BN, BDD or IAD) - n = 116 non-clinical - 90% female	- Laboratory experiment - Cross-over design, experimental conditions: (1) BC task; (2) checking vase - Induction of negative affect pre checking behavior-	- Disorder-specific BC instructions	- Negative affect - Arousal - Disorder-specific psychopathology - Psychophysiology	2
	Appearance-related safety behaviors
41	Patel & Cougle (2024)	- N = 94 - Women: n = 93 - Trans/non-binary: n = 1 - BDD, ED, and/or SAD diagnosis-	- Naturalistic setting, 4 weeks - Experimental conditions: (1) decrease appearance-related safety behaviors; (2) only self-monitoring of the behaviors	- Appearance Behaviors Checklist (Summers & Cougle, 2018)	- Appearance concerns - Psychopathology (symptoms of BDD, ED, or social anxiety) - Appearance importance - Depression - Trait anxiety - Reactivity to appearance-related stressors	3
42	Stentz et al. (2022)	- Non-clinical: N = 84 - 100% female	- Naturalistic setting - Experimental conditions: (1) decrease safety behaviors over 2 weeks; (2) no instruction	- All types of safety behaviors, assessed with the Appearance Behaviors Checklist (Summers & Cougle, 2018)	- ED pathology - Overvaluation of appearance	3
43	Summers & Cougle (2018)	- Non-clinical: N = 99 - 100% female	- Naturalistic setting, 1 week - Experimental conditions: (1) increase appearance-related safety behaviors; (2) decrease appearance-related safety behaviors; (3) increase academic studying	- Appearance Behaviors Checklist	- BDD pathology - Body dissatisfaction - Threat biases - Overvaluation of appearance - Reactivity to appearance-related stressors - Anxiety - Depressive feelings-	3
44	Wilver et al. (2020)	- Non-clinical: N = 84 - 100% female	- Naturalistic setting, 2 weeks - Experimental conditions: (1) decrease appearance-related safety behaviors; (2) no instruction	- Appearance Behaviors Checklist (Summers & Cougle, 2018)	- Social anxiety - BDD pathology - Body dissatisfaction - Threat biases - Cognitions about appearance - Depressive feelings	3

BN = bulimia nervosa; AN = anorexia nervosa; EMA = ecological momentary assessment; ED = eating disorder; CG = control group; BC = body checking; CBT = cognitive behavioral therapy; BDD = body dysmorphic disorder; IAD = illness anxiety disorder; SAD = social anxiety disorder

More than half of the studies (n = 24; 53,5%) comprised an exclusively female sample. In studies with mixed samples, the proportion of women generally exceeded that of men. Of the 43 studies, 20 investigated a clinical sample. The study designs were diverse, consisting of laboratory experiments (n = 18; 41.9%), (online) questionnaires (n = 5; 11.6%), treatment studies (n = 4; 9.3%), experimental field studies (n = 8; 18.6%), ecological momentary assessment (EMA; n = 7; 16.3%), and semi-structured interviews (n = 1; 2.3%). Risk of bias was acceptable overall and strong with regard to data collection methods (cf. supplementary material Figs. 2 and 3).

Study results

The outcomes of the individual studies are categorized by research question and mental disorder. An overview of the results is provided in Table 2.

Table 2.

Summary of main results according to the research question

Author, Publication Year	Setting	Sample	Summary of main results
(Emotional) state before checking behavior – first research question
Eating disorders
Hartmann, Cordes et al. (2019)	Online survey	Clinical (AN, BN)	↑ Negative affect (arousal, valence, anxiety, worry) from baseline to immediately before BC
Kraus et al. (2015)	EMA	Clinical (ED) Non-clinical control	↓ Positive affect before BC, No effects for negative affect
Pak et al. (2018)	EMA	Clinical (AN)	↑ Negative affect prior to BC
Body dysmorphic disorder
Veale & Riley (2001)	Questionnaire	Clinical (BDD) Non-clinical control	↑ Distress before gazing ↑ Depressive feelings when using the mirror
Hartmann, Cordes et al. (2019)	Online survey	Clinical (BDD)	↑ Negative affect (arousal, valence, anxiety, worry) from baseline to immediately before BC
Illness anxiety disorder
Hartmann, Cordes et al. (2019)	Online survey	Clinical (IAD)	↑ Negative affect (i.e. arousal, valence, anxiety, worry) from baseline to immediately before BC
Short-term effects of checking behavior – second research question
Eating disorders
Hartmann, Cordes et al. (2019)	Online survey	Clinical (AN, BN)	↓ Negative affect (i.e. arousal, valence, anxiety, worry) pre-post, 15 min and 60 min after BC
Guthoff et al. (2019)	Online survey	Non-clinical	↑ Negative affect for people with high concerns during and directly after BC ↓ Negative affect for people with high concerns from directly after to 15 min after BC
Wilhelm et al. (2020)	Online survey	Non-clinical	↑ Valence for people with high shape and weight concerns directly after BC ↓ Arousal and valence for people with high shape and weight concerns from directly after to 15 min after BC
Shafran et al. (1999)	Lab	Non-clinical	↓ Negative affect pre-post BC/neutralization
Kostopoulou et al. (2013)	Lab	Clinical (AN, BN)	↓ Negative affect pre-post BC/neutralization
Blechert et al. (2009)	Lab	Clinical (BN) non-clinical control	↓ Body satisfaction pre-post BC in BN group, ↑ in control group
Wilson et al. (2020)	Lab	Clinical (BN) non-clinical control	↓ Perceptual confidence pre-post BC in BN, no effect in control group no effects on body satisfaction
Shafran et al. (2007)	Lab	Non-clinical	↑ Body dissatisfaction directly after BC of disliked body parts; after 30 min, scores were comparable to before BC no effects on estimation of body size
Walker et al. (2021)	Lab	Non-clinical	↓ Body satisfaction pre-post BC for critical BC No effects for self-esteem or negative affect 1 week after BC task in lab: ↑ Body satisfaction in all groups ↓ Negative affect in critical compared to non-checking ↑ Self-esteem greater for critical and neutral BC than non-checking
Tanck et al. (2019)	lab	Non-clinical	↓ Body satisfaction pre-post BC in women, not in men ↑ Guilt pre-post BC in all participants
Hofschröer et al. (accepted)	lab	Clinical (BN) Non-clinical control	↑ Negative affect, psychopathology and heart rate compared to checking a vase
Engel et al. (2013)	EMA	Clinical (AN)	↑ Negative affect pre-post weighing No effect on positive affect
Kraus et al. (2015)	EMA	Clinical (ED) Non-clinical control	↑ Negative affect pre-post BC in all participants ↓ Positive affect pre-post BC in all participants
Pak et al. (2018)	EMA	Clinical (AN)	↑ Negative affect after BC
Body dysmorphic disorder
Oakes et al. (2017)	Semi-structured interview	Clinical (BDD)	↑ Comfort and safety, emotional support, engaging in safety behaviors
Hartmann, Cordes et al. (2019)	Online survey	cliNical (BDD)	↓ Negative affect (i.e. arousal, valence, anxiety, worry) pre-post, 15 min and 60 min after BC
Veale & Riley (2001)	Questionnaire	clinical (BDD) non-clinical control	↑ Distress after long mirror session for BDD
Mulkens & Jansen (2009)	Lab	Non-clinical	↑ Attractiveness in individuals with high appearance satisfaction pre-post BC No effect in individuals with low satisfaction
Veale et al. (2016)	Lab	Non-clinical	↑ Dissatisfaction with appearance in all groups pre-post gazing ↑ Sadness for internal focus of attention pre-post gazing
Barnier & Collison (2019)	Lab	Non-clinical	↓ Satisfaction, attractiveness, self-esteem pre-post focus on disliked body parts ↑ Distress, urge to change appearance and shame pre-post focus on disliked body parts
Chuah & Suendermann (2024)	Lab	Non-clinical	↓ Overall appearance satisfaction pre-post gazing ↓ Facial appearance satisfaction and perceived attractiveness pre-post focus on disliked body parts No effect on distress, urge to gaze, vividness and emotional quality of imagery
Windheim et al. (2011)	Lab	Clinical (BDD) non-clinical control	↑ Distress in both groups pre-post BC
Hofschröer et al. (submitted)	Lab	Clinical (BDD) non-clinical control	↑ Negative affect, psychopathology, and heart rate compared to checking a vase
Walker et al. (2012)	Lab	Non-clinical	↓ Body image satisfaction pre-post BC and 10 min later No direct pre-post effect on muscle dissatisfaction, but ↑ 10 min later
Cordes et al. (2017)	Lab	Non-clinical	↓ Body dissatisfaction pre-post BC ↑ Negative affect only when looking at pictures of the self
Möllmann et al. (2020)	Lab	Non-clinical	↑ Dissociation for 300s gazing (pre-post), stronger effects for own face No effects for attractiveness or perceptual uncertainty
Illness anxiety disorder
Hartmann, Cordes et al. (2019)	Online survey	Clinical (IAD)	↓ Negative affect (i.e. arousal, valence, anxiety, worry) pre-post, 15 min, and 60 min after BC
Doherty-Torstrick et al. (2016)	Online survey	Non-clinical	↑ Anxiety during and after online reassurance seeking for individuals with high compared to low IA
Abramowitz & Moore (2007)	Lab	clinical (IAD)	↓ Anxiety and urge to engage in SB in the SB group from before to directly after SB Time course: ratings remained higher than before exposure until 10 min after SB, no differences thereafter
Hofschröer et al. (submitted)	Lab	Clinical (IAD) non-clinical control	↑ Negative affect, psychopathology, and heart rate compared to checking a vase
Long-term consequences of checking behavior – third research question
Eating disorders
Farrel et al. (2019)	Treatment	Clinical (ED)	Lower BC 2 weeks after start of treatment predicted: ↓ eating disorder symptoms at end of treatment
Pellizzer et al. (2018)	Treatment	Clinical (ED)	Lower levels of BC predicted: ↓ ED pathology
Pellizzer et al. (2019)	Treatment	Clinical (ED)	Baseline BC sign. predictor of ED pathology at end of treatment No effects of change in BC during treatment on ED pathology or clinical impairment at end of treatment or 3-month FU
Calugi et al. (2017)	Treatment	Clinical (AN) Non-clinical control	Greater reduction of BC during treatment associated with: ↓ Weight concern and global ED pathology at end of treatment ↓ Shape concern, global ED pathology, and psychopathology at 12-month FU
Bailey & Waller (2017)	Naturalistic	Non-clinical	One day BC, every 15 min: ↑ Fear of uncontrollable weight gain No effects on body satisfaction or weight/shape and eating concerns
Opladen et al. (2022)	Naturalistic	Non-clinical	3-Fold increased BC: ↑ negative affect and depressive feelings, no effect on eating disorder symptoms typical BC: ↓ depressive feelings and anxiety
Geiger et al. (in press)	Naturalistic	Non-clinical	High body concern − 3-fold increased BC: ↑ negative affect, drive for thinness, and body dissatisfaction; typical BC: ↑ positive affect low body concern – 3-fold increased BC: ↑ drive for thinness generally no effects on bulimia and depressive feelings
Lavender et al. (2013)	EMA	Clinical (AN)	Daily BC frequency associated with: ↑ dietary restriction (not eating for 8 h, eating < 1200 cal) on the same and following day
Goeden et al. (2023)	EMA	Clinical (AN)	Higher engagement in BC: ↑ engagement in dietary restriction (increased fluid intake, skipping meals) in the next 3–4 h no effects on exercising, laxative use, and vomiting
Stefano et al. (2016)	EMA	Non-clinical	Higher frequencies of BC predicted: ↑ body dissatisfaction and negative affect
Sala et al. (2019)	EMA	Clinical (ED)	BC did not predict ED symptoms at 1-month follow-up
Illness anxiety disorder
Olatunji et al. (2011)	Naturalistic	Non-clinical	increased safety behaviors over 1 week compared to CG: ↑ health anxiety, hypochondriacal beliefs, and avoidance no effect on general anxiety
Reduction of appearance-related safety behaviors
Summers & Cougle (2018)	Naturalistic	Non-clinical	Increased safety behaviors over 1 week compared to CG: ↑ BDD symptoms, dissatisfaction, threat biases, overvaluation, reactivity, anxiety and depressive feelings No group differences at FU (1 week later)
Stentz et al. (2022)	Naturalistic	Non-clinical	Decreasing BC: ↓ bulimic symptoms, drive for thinness, and overvaluation compared to controls FU (2 weeks later): only ↓ drive for thinness stable
Wilver et al. (2020)	Naturalistic	Non-clinical	Decreased safety behaviors over 2 weeks compared to CG: ↓ Social anxiety, BDD symptoms, body dissatisfaction, negative biases and cognitions, depressive feelings
Patel & Cougle (2024)	Naturalistic	Clinical (ED, BDD and/or SAD)	Decreased safety behaviors over 4 weeks compared to CG: ↓ Social anxiety, BDD symptoms, ED symptoms, importance of appearance, depression, trait anxiety, reactivity to appearance-related stressors (urge to check and fear)

BC = body checking; BN = bulimia nervosa; AN = anorexia nervosa; BDD = body dysmorphic disorder; IAD = illness anxiety disorder; IA = illness anxiety; ED = eating disorder; SAD = social anxiety disorder; EMA = ecological momentary assessment; lab = laboratory experiment; CG = control group; FU = follow-up; SB = safety behavior; ↑ = increase; ↓ decrease

Emotional state before body checking

Eating disorders. We identified three studies, employing diverse designs, which compared the (emotional) state immediately before a body checking episode with the (emotional) state at various other time points. In a retrospective online survey, Hartmann, Cordes et al. [33] investigated individuals with self-reported diagnoses of anorexia nervosa or bulimia nervosa, among other disorders. Participants rated their negative affect (i.e., arousal, valence, and anxiety) both at baseline and immediately before a recalled body checking episode. The comparison revealed an increase in negative affect preceding body checking across all variables, in line with the theoretical model assumptions. The remaining two studies utilized EMA to observe the (emotional) state preceding body checking in participants’ daily lives. In a clinical sample from an outpatient psychotherapy center, Kraus et al. [7] found that situations immediately before body checking were characterized more by a lower degree of positive affect than by an increase in negative affect. In contrast, the other study focused on participants with anorexia nervosa and reported an increase in negative affect prior to engaging in body checking [34] (cf. Table 2).

Body dysmorphic disorder For body dysmorphic disorder, our search identified only two retrospective studies that investigated the (emotional) state preceding a body checking episode. Both studies are in line with the theoretical model assumptions. In a questionnaire survey, Veale and Riley [35] found that individuals with body dysmorphic disorder were more inclined to use mirrors when feeling depressed and reported higher distress before mirror use compared to a non-clinical control group. The transdiagnostic online survey conducted by Hartmann, Cordes et al. [33] also found that individuals with self-reported body dysmorphic disorder showed an increase in negative affect (i.e., arousal, valence, and anxiety) prior to body checking (cf. Table 2).

Illness anxiety disorder For illness anxiety disorder, only one study, the aforementioned transdiagnostic online survey by Hartmann, Cordes et al. [33], addressed the first research question. Similar to eating disorders and body dysmorphic disorder, individuals with a self-reported diagnosis of illness anxiety disorder retrospectively described their affective state prior to body checking episodes as characterized by an increase in negative affect (i.e., arousal, valence, and anxiety) (cf. Table 2).

Short-term effects of body checking

Eating disorders Our literature search identified a total of 15 studies examining the short-term effects of body checking in the context of eating disorders. Three of these studies utilized a retrospective questionnaire design, in which participants provided responses about a remembered body checking episode; the studies investigated both direct pre-post effects and the time course of recalled body checking episodes. In the aforementioned transdiagnostic study, individuals with self-reported diagnoses of anorexia nervosa or bulimia nervosa reported a significant decrease in negative affect (i.e., arousal, valence, anxiety, and worry) from immediately before to immediately after a remembered recent body checking episode. This decrease continued over time for up to one hour after body checking, corresponding to the theoretical model assumptions [33]. Similar designs were employed in the remaining two questionnaire studies, in which non-clinical participants with high weight and shape concerns were asked to recall body checking episodes involving their least liked body parts. In both studies, participants initially reported an increase in negative affect immediately after checking. However, over time, this negative affect significantly decreased, either reaching baseline levels [36] or decreasing even further [37], supporting the theoretical model assumptions of a decrease over time.

Additional evidence comes from laboratory studies, particularly those exploring the experimental provocation of thought-shape fusion, which is a cognitive distortion arising when thoughts about consuming a forbidden food lead to feelings of fatness or moral wrongdoing [38]. In line with cognitive-behavioral models, these studies demonstrated that the effects of this manipulation, inducing anxiety, guilt, and a sense of feeling fat, could be mitigated by safety behaviors. This finding was observed in both undergraduate students [39] and a clinical sample of individuals with anorexia nervosa or bulimia nervosa [38]. It is noteworthy, however, that in both studies, only approximately one third of participants engaged in body checking, while the remaining participants employed alternative corrective behaviors such as mental neutralizing (e.g., imagery exercises or vomiting).

A study by Wilson et al. [40] yielded different results. Female participants with bulimia nervosa and a non-clinical control group were asked to check their least liked body parts in front of a mirror for 10 min. Surprisingly, the checking task had no effect on body satisfaction ratings in either group. However, participants with bulimia nervosa reported a significant decrease in perceptual confidence after checking their body. Two additional laboratory studies examined the direct effects of body checking in a non-clinical female sample [41, 42]. Participants were instructed to either neutrally observe their bodies as a whole or focus on disliked body parts. In both studies, body dissatisfaction increased immediately after focusing on least liked body parts. However, the study by Walker et al. [42] found no effects on self-esteem or negative affect. In the study by Shafran et al. [41], in a subsequent assessment conducted 30 min after body checking, body dissatisfaction scores were comparable to before the experimental manipulation. In the study by Walker et al. [42], a second well-being assessment was conducted one week after the laboratory appointment. Surprisingly, all participants reported an increase in body satisfaction. In the group that underwent a critical body checking session in the laboratory, negative affect significantly decreased compared to the control group. In both groups that underwent a body checking task, an increase in self-esteem was observed. Contrary to the theoretical model assumptions, these findings suggest an initial deterioration in the affective state (in this case, body satisfaction) immediately after engaging in body checking. However, the effects were not long-lasting [41], and in some instances, there was even an improvement in well-being with a delay following body checking [42]. Similar pre-post findings were also reported by Tanck et al. [43], who explored potential gender differences between men and women when checking negatively/positively valanced body parts. While women reported a decrease in body satisfaction after checking their disliked body parts, analogous to the results described above, men reported an increase in satisfaction regardless of which body parts they checked. However, in both groups, guilt increased after body checking. Further evidence comes from a research project that included participants with bulimia nervosa, body dysmorphic disorder, or illness anxiety disorder as well as a non-clinical sample [44, 45]. In this laboratory experiment, negative mood was initially induced in accordance with the assumptions of cognitive-behavioral models. Subsequently, the participants were instructed to either perform a disorder-specific checking task in the mirror or to describe the characteristics of a vase in the control condition. The assumptions of cognitive-behavioral models could not be confirmed; all groups showed an increase in negative affect and psychopathology after the body checking task. Transdiagnostic exploratory analyses also revealed a higher increase in negative affect and psychopathology in participants with bulimia nervosa and body dysmorphic disorder compared to those with illness anxiety disorder [45]. Moreover, all disorder groups showed an increase in heart rate and skin conductance as a consequence of the checking task.

Further evidence concerning the short-term effects of body checking has emerged from studies conducted in participants’ everyday lives using EMA. Contrary to theoretical model predictions, body checking has been found to lead to increased negative affect among participants with anorexia nervosa [34, 46], in a sample with mixed eating disorder diagnoses, and in a non-clinical control group [7]. In the study by Kraus and colleagues [7], contrary to the theoretical postulates, body checking also led to a decrease in positive affect, while the study by Engel et al. [46] found that weighing oneself, as a specific checking behavior, had no influence on positive affect. Notably, none of the three EMA studies considered the time course after a body checking episode (cf. Table 2).

Body dysmorphic disorder Regarding body dysmorphic disorder, our literature search identified 14 studies investigating the short-term effects of body checking. In a semi-structured interview conducted by Oakes et al. [47], individuals with body dysmorphic disorder reported, in line with the predictions of cognitive-behavioral models, that engaging in appearance-related behaviors (including not only body checking but also other actions such as camouflaging) leads to a feeling of comfort and safety, offering positive emotional support. This aligns with the results of the aforementioned transdiagnostic study, which indicated a reduction in anxiety, arousal, and general negative affect from before, to during, to three time points after body checking in participants with self-reported body dysmorphic disorder when recalling a recent body checking episode [33]. However, a questionnaire study by Veale and Riley [35] yielded different findings, with participants with body dysmorphic disorder retrospectively reporting increased distress after a body checking episode.

Further evidence has been provided by laboratory studies with various different designs: Mulkens and Jansen [48] examined a non-clinical sample categorized into subgroups with high and low satisfaction with their appearance. Participants were instructed to either check their own faces in the mirror or view a photograph of a stranger and to rate the attractiveness of the faces before and after gazing. Interestingly, individuals with high appearance satisfaction reported an increase in perceived attractiveness for their own faces, while those with low satisfaction reported an increase in the perceived attractiveness of the stranger’s face. In three additional studies with non-clinical samples, attentional focus was experimentally manipulated during mirror gazing. In the study by Veale et al. [49], contradicting theoretical model assumptions, all participants rated themselves as more dissatisfied with their appearance after mirror gazing. However, an increase in sadness was only found in the condition with an internal focus of attention (i.e., focusing on what one feels when looking in the mirror). Barnier and Collison [50] instructed their participants either to simply look in the mirror from a distance of one meter (low self-focused attention) or to focus closely on their face or disliked body parts (high self-focused attention). The high self-focused attention condition resulted in lower satisfaction, as participants rated themselves as less attractive and more distressed about their own reflection. They also reported a stronger urge to change their appearance, an increase in shame, and a decrease in self-esteem. These results contradict the predictions of cognitive-behavioral models. Moreover, they are partly supported by a further study applying a comparable design, which reported that mirror gazing generally led to a lower level of appearance satisfaction but that the perceived attractiveness and satisfaction with the face only declined in the group with high self-attention [51]. However, in contrast to the study by Barnier and Collison [50], the gazing task had no effect on the urge to check or the experience of distress. Chuah and Suendermann [51] also investigated whether the emotional quality and vividness of appearance-related imagery changed as a result of mirror gazing, which was not found to be the case. Nevertheless, similar to some studies on eating disorders, the authors only conducted direct pre-post comparisons and did not further examine the time course after body checking. In another laboratory study, individuals with body dysmorphic disorder and a non-clinical control group were instructed to look in the mirror, with an experimental manipulation of the duration of sessions (short check vs. long gazing; [23]. Contrary to theoretical model assumptions, all participants reported an increase in distress after looking in the mirror. Group comparisons also revealed that individuals with body dysmorphic disorder felt less certain about their appearance and had stronger urges to continue, but also to avoid looking in the mirror. The above-mentioned transdiagnostic laboratory study [44, 45] also examined subjects with body dysmorphic disorder. The results indicated an increase in arousal and psychopathology, thus likewise challenging the theoretical model assumptions.

Evidence from two laboratory studies involving male participants similarly contradicts the theoretical model assumptions. In an all-male sample, Walker et al. [52] demonstrated that the way in which men engaged in body checking (either inspecting their entire body or focusing on specific disliked body parts) did not have a significant impact: A decrease in body satisfaction was observed in all male participants following body checking, which even remained after 10 min. However, the checking task had no immediate effect on muscle dissatisfaction, with an increase in muscle dissatisfaction only becoming evident after a 10-minute delay. In an eye-tracking study [53], weight-training men were instructed to look at pictures of themselves as well as pictures of normal, muscular, and hyper-muscular men. Regardless of which picture they were looking at, a decrease in body dissatisfaction was observed. An increase in negative affect was only evident when men were confronted with their own picture. The two remaining laboratory studies [54, 55] utilized face-gazing paradigms to investigate female, non-clinical subjects. Ten minutes of focusing on the nose of a photographed face led to an increase in dissociation and a decrease in feelings of attractiveness, while the confidence of attractiveness ratings or uncertainty of perception were not affected by gazing [54]. In a subsequent study, the same research group experimentally manipulated stimuli and durations of gazing, and observed no effects on attractiveness ratings or perceptual uncertainty. However, 5 min of gazing led to a significant increase in dissociation, and this effect was most pronounced when looking at one’s own face in the mirror [55] (cf. Table 2).

Illness anxiety disorder We identified a total of five studies that examined the short-term effects of body checking for illness anxiety disorder. In the aforementioned online transdiagnostic retrospective study, analogous to the findings for eating disorders and body dysmorphic disorder, participants with self-reported illness anxiety disorder showed a decrease in anxiety, arousal, and general negative affect. This decrease was observed from before, to during, to the three time points after recalling a recent body checking episode [33]. These findings align with the theoretical model assumptions, which suggest a short-term emotion regulation effect of body checking. Another online questionnaire study, which categorized a community sample into subgroups with high/low illness anxiety, yielded different findings [56]. While individuals with high illness anxiety recalled increased anxiety during and after online reassurance seeking (i.e., searching on the internet for information about symptoms), those with low illness anxiety reported relief after online checking. Additionally, individuals who reported a long duration of checking were more likely to feel bad afterward than those who only searched for information for a short time. The third study identified in our literature search examined a clinical sample in a laboratory setting, exposing participants to a personally relevant illness trigger [10]. Participants were randomized to either a response prevention group or a safety behavior group (i.e., checking, taking medication, googling symptoms, etc.). Performing safety behaviors immediately resulted in a decrease in anxiety and the urge to engage in safety behaviors, as postulated by the cognitive-behavioral models. However, the ratings remained significantly higher than before the exposure to the illness trigger until 10 min after the use of safety behaviors. Thereafter, no significant differences were found. The aforementioned transdiagnostic laboratory study also found an increase in negative affect and psychopathology after the checking task in participants with illness anxiety disorder, but this increase was lower than for participants with bulimia nervosa or body dysmorphic disorder [45] (cf. Table 2).

Long-term consequences of body checking

Eating disorders In total, we found 11 studies that investigated the long-term consequences of checking behavior for eating disorders. Four of these studies examined the influence of checking behavior in the context of eating disorder treatment. Consistent with the theoretical model assumptions, body checking was found to be a significant predictor of eating disorder psychopathology at the end of treatment [57–59]. Additionally, a reduction in body checking was associated with improvements in eating disorder symptomatology and general pathology in individuals with anorexia nervosa [60]. Three experimental studies with non-clinical samples investigated the long-term consequences of body checking in a naturalistic setting. Bailey and Waller [61] asked participants to check their wrist size every 15 min for one whole day, and found no effects on body satisfaction, weight/shape concern, or eating concern. However, consistent with the postulates of the cognitive-behavioral models, participants reported an increase in the fear of uncontrollable weight gain after body checking compared to the condition without checking. In the study by Opladen et al. [62], body checking was also manipulated as part of a cross-over design, with participants either carrying out their typical amount of body checking or increasing their typical frequency of checking by a factor of three. In the typical checking condition, participants reported a decrease in depressive feelings and anxiety. However, enhanced body checking led to an increase in negative affect and depression, aligning with the theoretical model assumptions. Despite this, the intensification of body checking had no effect on eating disorder symptoms. These findings were only partially replicated in a subsequent study in which participants were divided into groups with high and low body concern [63]: While the authors reported no changes in bulimic or depressive symptoms for any of the participants over the study period, women with high body concern reported a decrease in body image-related symptoms (i.e., drive for thinness and body dissatisfaction) and a significant increase in negative affect following three days of enhanced body checking. Furthermore, our literature search revealed four publications that investigated the long-term consequences of body checking in the daily lives of participants using EMA. Consistent with the predictions of the theoretical models, a study by Lavender et al. [64] involving individuals with anorexia nervosa (and subthreshold anorexia nervosa) found that the daily frequency of body checking was related to dietary restriction (i.e., not eating for 8 h, eating < 1200 cal) on the same day as well as on the following day. An additional publication based on the same dataset showed that performance of body checking led to a greater engagement in behaviors aimed at weight loss by means of dietary restriction (i.e., skipping meals and increasing fluid intake to curb appetite) in the following hours, while there were no effects on exercising, laxative use, and vomiting [65]. In another study with a non-clinical sample employing a five-day EMA observation period, higher frequencies of body checking were found to predict higher levels of body dissatisfaction and negative affect [66], also supporting the theoretical model predictions. In contrast, in a 7-day EMA study including individuals with eating disorder, body checking did not predict eating disorder symptoms at a 1-month follow-up [67] (cf. Table 2).

Body dysmorphic disorder In the context of body dysmorphic disorder, we were unable to find any studies that investigated the long-term effect of body checking in accordance with the research question. However, indirect conclusions can be drawn from studies that focused primarily on the effects of reducing appearance-related safety behaviors (including not only body checking but also other behaviors such as camouflaging and grooming; [68]. In total, our literature search yielded four studies that focused mainly on the effects of decreasing appearance-related safety behaviors. All of these studies implemented a comparable experimental design in a naturalistic setting, and three of the studies were conducted with non-clinical samples. In the study by Summers and Cougle [69], participants were instructed to either increase or decrease their appearance-related safety behaviors for one week. Compared to participants in a control group in which participants were asked to increase their academic learning behaviors, those who increased their safety behaviors showed higher body dysmorphic disorder symptoms, body dissatisfaction, anxiety, depressive feelings, and reactivity to appearance-related stressors, aligning with the theoretical model assumptions. However, the effects of intensified engagement in safety behaviors were not found to be long-lasting, as no group differences were observed at a one-week follow-up. Moreover, participants who were asked to reduce appearance-related safety behaviors did not significantly differ from the control group. In a subsequent investigation [68, 70], the time period for reducing safety behaviors was extended to two weeks. Compared to a control group that did not receive any instructions, the decreased engagement in safety behaviors resulted in reduced social anxiety, body dysmorphic disorder symptoms, body dissatisfaction, and depressive feelings [68]. Furthermore, participants who reduced their safety behaviors reported a reduction in bulimic symptoms, drive for thinness, and overvaluation of weight after the two weeks [70], supporting the assumptions of the cognitive-behavioral models. However, only the decrease in drive for thinness remained stable at a two-week follow-up. Drawing on these findings, in a subsequent study with a clinical sample (participants met the criteria for at least one diagnosis out of eating disorder, body dysmorphic disorder, and/or social anxiety disorder), participants were guided to reduce their appearance-related safety behaviors for four weeks, which was found to lead to a reduction in psychopathology [71] (cf. Table 2).

Illness anxiety disorder Our literature search yielded only one study that addressed the third research question related to illness anxiety disorder. This experimental investigation, conducted in a naturalistic setting, examined the effects of a one-week intensification of health-related safety behaviors (e.g., checking, taking medication, avoidance) in a non-clinical sample [72]. Compared to the control group, the intensified engagement in safety behaviors led to increased health anxiety, hypochondriacal beliefs, and avoidance, as predicted by the cognitive-behavioral models. The participants did not differ in general anxiety after this week (cf. Table 2).

Discussion

The objective of this study was to comprehensively analyze the existing empirical evidence regarding the mechanisms underlying body checking and to critically review studies with respect to the theoretical assumptions of the cognitive-behavioral explanatory models, while also identifying potential research gaps. With regard to the first research question, which explored participants’ emotional state preceding body checking episodes, the findings consistently support the theoretical model assumptions across eating disorders, body dysmorphic disorder, and illness anxiety disorder. Situations immediately before body checking were generally marked by increased negative affect or decreased positive affect. However, given the limited number of available studies, caution is warranted in drawing definitive conclusions from these results. In contrast, the evidence for the second (short-term effects of body checking) and third (long-term consequences of body checking) research questions is less uniform, suggesting the need to explore which factors influence whether the emotional state improves or deteriorates following body checking. The inconsistent findings may be attributable to differences in disorder severity, study settings, measurement time points, and dependent variables. Alternatively, the trajectory of the emotional state during and after body checking episodes might vary depending on the specific function body checking serves, which may differ from the function of emotion reduction that is primarily assumed across the various etiological models.

Although the etiological models propose shared features across disorders regarding the function and impact of body checking, there are substantial differences between the different disorders. Notably, distinctions arise in the focus of fears and worries, such as body image disturbances in eating disorders and body dysmorphic disorder [73] as opposed to the fear of illness in illness anxiety disorder [74]. However, drawing conclusions about potential differences between these disorders regarding the mechanisms underlying checking behavior remains challenging due to the limited number of available studies. While research on eating disorders is more extensive, some disorders, such as illness anxiety disorder, are underrepresented, with only a small number of studies to date. Moreover, standardized designs across multiple disorders are lacking. Moreover, participants’ diagnoses were self-reported, albeit substantiated by high scores on disorder-relevant questionnaires. Therefore, further investigations employing varied standardized designs are needed to enable comprehensive comparisons across disorders. A further study with a transdiagnostic focus is currently being prepared for publication [45]. According to the initial findings, a body checking task in the laboratory led to an increase in negative affect, psychopathology, and physiology, which was comparatively higher for participants with bulimia nervosa and body dysmorphic disorder than for those with illness anxiety disorder.

Considerable variability in study settings not only exists across different disorders but also within specific diagnostic groups. This diversity encompasses experimental laboratory studies (e.g., [10, 49]), which are difficult to compare with studies utilizing retrospective assessments (online or offline; e.g., [33, 35]) or with investigations in participants’ daily lives using EMA (e.g., [7, 66]). The observed discrepancies in the results may be partly attributable to these variations in study designs. Furthermore, certain research questions were not comprehensively represented across all study designs within specific diagnostic groups. For instance, for body dysmorphic disorder, there were no studies regarding the second research question (short-term effects of body checking) that utilized EMA in participants’ everyday lives. Consequently, systematic examinations of checking behavior and the emotional trajectory during and after body checking across multiple settings are still lacking.

The inconsistencies observed both across and within disorders may stem not only from different study settings but also from variations in the measurement time points. Specifically, when examining the short-term effects of body checking, the assessment of (emotional) state in most experimental studies occurred immediately after the termination of the checking episode (e.g., [7, 23, 49]). While the etiological models discussed provide general expectations about the time course of body checking effects, none offer precise information regarding specific time intervals. Generally speaking, they contrast short-term reductions in negative affect with enduring negative effects of body checking in the long term. However, studies employing comprehensive measurement time points before, during, and at multiple intervals after body checking in order to understand the effects across different latencies are still lacking. Moreover, there is ambiguity regarding when the long-term consequences of body checking should be considered to manifest. Theoretical models suggest that these effects emerge through repeated body checking, a criterion which we employed in order to categorize studies relevant to each research question. Accordingly, studies examining the effects of a single checking episode were categorized a priori as short term, while those investigating the consequences of repeated episodes were categorized as long term.

Studies examining the impact of reducing body checking on treatment outcomes provided indirect evidence of the long-term consequences of body checking (e.g., [57, 60]). However, given their focus on reduced body checking, the ability of these studies to address the long-term consequences of increased body checking is limited, and their results may not be directly applicable to our research question and the postulates of the etiological models. In contrast, other experimental studies specifically investigated body checking at various time intervals, such as every 15 min throughout a single day [61], for three consecutive days [62], or over a period of one or two weeks [67, 70]. Similarly, observational studies conducted in participants’ everyday lives using EMA covered time frames ranging from a few days [64, 66] to a one-month follow-up assessment [67].

It remains questionable whether the occurrence of long-term effects, as postulated in the theoretical models, can be concluded from the relatively short time intervals applied in the studies. The theories describe complex processes that are assumed to contribute to the maintenance of disorders. For example, in their integrated cognitive-behavioral theory of eating disorders, Williamson et al. [20] posit that maladaptive behaviors (such as body checking, restrictive eating, or self-induced vomiting) lead to the confirmation of disorder-specific beliefs and fears (e.g., fear of fatness, overconcern with weight/shape), thereby strengthening the weight- and shape-related self-schema and consequently maintaining the disorder. It is debatable whether such effects can be detected after several days, as investigated in current study designs. Future research on the mechanisms of action underlying body checking would benefit from incorporating an additional time dimension to specifically explore longer-term effects of body checking. Additionally, it appears that there is a need for longitudinal study designs with varying time latencies in order to comprehensively understand the dynamics of the impact of body checking.

Indeed, potential contradictions in the evidence might also be rooted in differences in the dependent variables or measures used across studies. For instance, the studies vary considerably in the use of global and general measures, such as non-disorder-specific anxiety (e.g., [10, 33]), positive/negative affect (e.g., [7]), self-esteem (e.g., [42]), or depressive feelings (e.g., [69]), as opposed to disorder-specific outcomes like body (dis)satisfaction (e.g., [66, 75]) or health anxiety (e.g., [72]).

Furthermore, the studies show discrepancies in how constructs were measured. In the context of eating disorders, for example, Tanck and colleagues [43] used a standardized questionnaire to assess body dissatisfaction, namely the Body Image States Scale (BISS; [76]), while another study [41] employed self-generated visual analogue scales. It is worth noting that the studies to date have primarily relied on dependent variables obtained through self-report. Future research could therefore explore additional variables that can only be consciously influenced to a limited degree, such as indices of autonomic activation [77, 78], which have not yet been examined in the context of body checking.

Certainly, the incorporation of psychophysiological measures like heart rate, heart rate variability, or skin conductance could enhance the understanding of individuals’ responses to body checking. These measures can be easily and economically obtained using superficial electrodes and have been shown to be valuable for assessing affective states, including valence and arousal [79, 80]. Despite their potential, psychophysiological responses to exposure to one’s body are not thoroughly understood, and existing studies have yielded inconsistent or contradictory findings. For example, an experimental study found that an increase in the emotional response during exposure to one’s own body in the mirror was accompanied by an increase in skin conductance but not heart rate [81]. Conversely, another study reported a decrease in heart rate, heart rate variability, and skin conductance while participants viewed their own bodies on a computer screen [82]. However, studies examining these aspects in the context of body dysmorphic disorder and illness anxiety disorder are currently lacking. Integrating these psychophysiological variables into the designs of future studies could potentially provide insights into the differences in reactions to body checking across and within various disorders. A recent transdiagnostic laboratory study (publication currently in preparation) took this into account by recording the effects of body checking on peripheral physiology [45]. Participants with bulimia nervosa, body dysmorphic disorder, or illness anxiety disorder experienced an increase in heart rate and skin conductance after performing disorder-specific body checking under experimental laboratory conditions.

Variations in how checking behavior is conceptualized and measured across different studies might also contribute to the contradictory results. Some studies focused on specific checking strategies, such as checking one’s wrist size [61], weighing oneself [46], or examining specific body parts, for instance by checking that one’s thighs are not touching or checking joints and bones for perceived fat [34, 64]. Others aimed to capture disorder-specific checking behavior more broadly in participants’ daily lives (e.g [7, 66]). Moreover, in some studies, participants were instructed to check their bodies in front of a mirror in standardized laboratory settings (e.g [41, 42, 45]), while others used measures like the Body Checking Questionnaire (BCQ; [83]) to assess body checking (e.g [57, 58]). These differences should be considered when interpreting the study results, as conclusions about checking in general may not be applicable if, for instance, only specific strategies such as weighing oneself are examined. Furthermore, it may make a difference whether participants are able to perform their usual body checking or are instructed to check their bodies under standardized laboratory conditions. Additionally, empirical evidence is limited with regard to how, precisely, body checking is carried out in terms of frequency, duration, examined body parts, or focus of attention. This lack of clarity may have an impact on authenticity when attempting to recreate body checking under laboratory conditions.

Accordingly, there is a clear need for more ecologically valid investigations conducted in participants’ daily lives, which capture various aspects of body checking. Such studies could help delineate differences in the nature of body checking across different diagnostic categories and between clinical and subclinical populations.

Lastly, while all etiological models suggest the reduction of negative affect as the underlying function of body checking, the empirical data obtained so far do not clearly support this notion. Rather, other functions or aims might be relevant as well, such as preventing negative consequences, attaining certainty, or the motivation to pursue strenuous disorder-related behaviors (e.g [16, 33, 84, 85]). Furthermore, studies suggest that the performance of body checking might also be impacted by certain beliefs, such as the belief that resisting the urge to perform body checking may make one feel worse [35, 86]. The aim of preventing negative consequences might align with the reduction of negative affect, as postulated by the etiological models mentioned above. For example, in illness anxiety disorder, this aim could involve preventing a deadly illness by identifying early warning signs. In body dysmorphic disorder, it might focus on ensuring that the perceived defect is still adequately covered up to avoid embarrassing oneself in front of others. Hence, an anticipated course of emotional activation might be comparable across disorders in the sense of beliefs that body checking assists in preventing negative consequences. From their EMA data in eating disorders, Kraus and colleagues [7] derived another potential function, suggesting that body checking might serve as a self-motivation strategy. Specifically, through the potentially off-putting focus on one’s weight or shape, and particularly subjectively unattractive body parts, individuals might be driven toward restrictive eating, purging, or overexercising. Additionally, body checking might also serve the function of attaining certainty, with various studies demonstrating a high intolerance of uncertainty in eating disorder pathology [87], body dysmorphic disorder [88], and illness anxiety disorder [89]. For example, in their questionnaire study, Veale and Riley [35] found that individuals with body dysmorphic disorder look in the mirror in the hope of seeing something different from their internal body representation or at least of feeling more comfortable with their appearance. To explain this, the authors suggested that individuals with body dysmorphic disorder essentially experience great insecurity about their representation of themselves while also having a strong need to know exactly how they look. By looking in the mirror, this demand is briefly rewarded; however, Veale and Riley [35] postulated that as soon as individuals with body dysmorphic disorder stop checking, the focus returns to the internal body representation, and the insecurity returns.

Furthermore, the function or goal of body checking may change if the behavior is performed more frequently and becomes habitual. In the context of anorexia nervosa, for example, it can be assumed that repeatedly weighing oneself initially serves the purpose of checking the success of strict dieting, thus increasing the experience of self-control. However, dysfunctional processing during checking, such as confirmation bias as postulated by Fairburn et al. [16], might lead to a reinforcement of concerns (e.g., unintentional weight gain) and contribute to the experience of losing control over one’s weight and shape. According to Fairburn and colleagues [16], the hypervigilant monitoring of the body, which increasingly occurs as a result of these processes, can become highly aversive. In turn, the loss of self-control is repeatedly confirmed, often leading to severe avoidance behavior.

Implications

The concept of checking behavior originated in the field of obsessive–compulsive disorder [5, 6] and was subsequently extended theoretically to body-related disorders, namely eating disorders [20], body dysmorphic disorder [18], and illness anxiety disorder [19]. However, the findings do not provide conclusive support for the assumptions of the models [18–20] that postulate a negative reinforcement mechanism of body checking in terms of negative affect. This may indicate that adaptations of the cognitive-behavioral models of eating disorders [20], body dysmorphic disorder [18], and illness anxiety disorder [19] could be warranted, particularly with respect to questioning the presumed causal link between body checking and short-term affect reduction and that, consistent with the considerations of Shafran et al. [17], the transfer from compulsive checking to body checking may not be empirically valid.

The findings could further pave the way for the development of a transdiagnostic body checking model. Such a model might, in turn, contribute to the creation of transdiagnostic clinical interventions addressing this phenomenon. A deeper transdiagnostic understanding of the aims and functions of body checking and their association with affective states during body checking episodes could significantly impact the future (re)design of disorder-specific psychotherapeutic strategies to target body checking. For example, exposure with response prevention, a cognitive-behavioral treatment strategy recommended across the various disorders (e.g [11, 24, 90]), might need to be reconsidered. Currently, this strategy is based on the mechanism of negative reinforcement, specifically the reduction of negative affect through body checking. Given that body checking did not reduce negative affect in all analyzed studies, it may be worth reconsidering whether therapeutic rationales should continue to emphasize the reduction of body checking as a therapeutic goal. Although the results did not demonstrate the proposed negative reinforcement mechanism through body checking, the observed short- and long-term increases in negative affect following body checking suggest that engaging in this behavior contributes to heightened negative affect and the maintenance of disorder-specific psychopathology. Based on these findings, it can therefore be assumed that refraining from body checking remains a potentially appropriate therapeutic intervention (cf [91]), even in case the negative reinforcement mechanism does not apply.

In summary, the present review highlights some promising approaches in the research on the mechanisms of action underlying body checking. Given the considerations and the limitations of previous research, future studies should incorporate designs that encompass multiple disorders, diverse settings, multiple measurement time points (particularly after body checking), and different dependent variables, including measures that do not rely on self-report, such as psychophysiology. Moreover, it is crucial that studies clearly distinguish between the effects of a single checking behavior episode and repeated, habitual body checking.

Supplementary Information

Below is the link to the electronic supplementary material.

Author contributions

VH coauthored and edited the original draft with M-BV and analyzed and interpreted the data. M-B-V coauthored the original draft with VH and analyzed and interpreted the data. SV conceptualized the study design and reviewed and edited the manuscript. ASH conceptualized the study design and reviewed and edited the manuscript. All authors read and approved the final manuscript.

Funding

The authors declare no funding sources.

Data availability

The datasets analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

The study involving human participants was approved by the Ethics Committee of Osnabrueck University (51/2019).

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.