Understanding Adolescent Non-Suicidal Self-Injury: A Narrative Review of Theoretical Models and Evidence-Based Psychotherapies

Abstract

Objectives

Adolescent non-suicidal self-injury (NSSI) is a marker of severe emotional distress and a significant public health concern. This narrative review aimed to synthesize major theoretical models explaining the psychopathology of NSSI and critically evaluate the efficacy of evidence-based psychotherapies using the most recent high-level evidence.

Methods

We searched articles in major academic databases published from January 2000 up to June 2025. We prioritized studies on adolescents, including efficacy studies (randomized controlled trials and meta-analyses) addressing NSSI as a primary outcome, and key theoretical papers.

Results

NSSI was understood through integrated models, prominently featuring emotion dysregulation (biosocial theory), experiential avoidance (cognitive-behavioral models), impaired mentalization (attachment theory), and operant conditioning (functional model). The synthesis of high-level evidence, including a 2021 review from Cochrane, indicated that dialectical behavior therapy (DBT) had the strongest empirical support (high-certainty evidence) for reducing adolescent NSSI. However, while mentalization-based treatment, acceptance and commitment therapy, and attachment-based family therapy offered promising mechanism-specific approaches, evidence for their effectiveness for NSSI was preliminary or uncertain.

Conclusion

DBT is currently the first-line treatment for NSSIs in adolescents. However, the field must move toward personalized care. Future research should focus on validating alternative therapies through head-to-head randomized controlled trials, identifying the core change mechanisms across treatments, and implementing stepwise care models to improve accessibility.

INTRODUCTION

Non-suicidal self-injury (NSSI) is defined as the deliberate, self-inflicted damage to one’s body without suicidal intent. Common manifestations include cutting, burning, scratching and self-hitting. NSSI is distinct from socioculturally sanctioned body modifications (e.g., tattoos and piercings) and minor normative behaviors (e.g., nail biting) [1].

NSSI gained formal recognition as a clinically significant issue in 2013 when the American Psychiatric Association (APA) included it as a “Condition for Further Study” in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) [2]. The DSM-5 criteria for NSSI diagnosis require engagement in self-injury for five or more days within the past year (Criterion A), with the intention of relieving negative affect, resolving interpersonal difficulties, or inducing positive feelings (Criterion B). Furthermore, the diagnosis requires that the behavior is preceded by negative affect or preoccupation with self-injury (Criterion C), is not socially sanctioned (Criterion D), causes clinically significant distress or functional impairment (Criterion E), and is not better explained by another mental disorder (Criterion F). The establishment of these diagnostic criteria provided a framework for systematic research and clinical approach to NSSI.

NSSI is a significant public health issue, particularly prevalent in adolescence. Multiple systematic reviews and meta-analyses have consistently reported a lifetime prevalence of approximately 17%–22% in community adolescent samples. This rate escalated substantially in the clinical population, ranging from 40%–80% [3]. These reports underscore the frequent use of NSSI as a coping mechanism among youths with mental health problems. NSSI onset typically occurs in early adolescence (ages 12–14) [4,5], coinciding with a developmental stage characterized by heightened emotional volatility and identity exploration.

The clinical relevance of NSSI extends beyond physical injury. It represents an externalized manifestation of intense psychological distress and serves as a potent warning signal of the risk of subsequent severe psychopathology. Longitudinal studies have established that NSSI in early adolescence is an independent risk factor for the onset of various psychiatric disorders, including depression, anxiety, and eating disorders, in late adolescence and early adulthood [6]. Furthermore, NSSI significantly diminishes quality of life and impairs academic and interpersonal functioning [7].

The most critical clinical concern is the robust association between NSSI and suicidal thoughts and behaviors. Although NSSI is “non-suicidal” by definition, this distinction pertains only to the immediate intent. Paradoxically, NSSI substantially increases the risk of suicide. However, the relationship between NSSI and suicide is complex. While some argue that NSSI serves an “anti-suicide” function by providing immediate relief from overwhelming distress, thereby preventing escalation to suicidal behavior [8], longitudinal evidence strongly supports that NSSI is detrimental in the long term. NSSI is recognized as one of the strongest single predictors of future suicide attempts, often demonstrating predictive validity exceeding that of established risk factors such as de-pression and hopelessness. Up to 70% of adolescents in clinical settings reported co-occurrence of NSSI and suicide attempts [5], supporting the hypothesis that NSSI functions as a “gateway” to suicide [9]. Specifically, repeated engagement in NSSI may facilitate the development of “acquired capability for suicide” through habituation to pain and the fear of death [5], thereby increasing the capacity to enact lethal suicidal behavior.

In this context, adolescent NSSI must be regarded not merely as a problematic behavior but as a clinical crisis requiring immediate and effective therapeutic intervention to prevent escalation to life-threatening conditions. NSSI primarily functions as a maladaptive coping strategy aimed at regulating overwhelming negative affect [10]. Temporary relief from intense emotional distress following the act is learned and maintained through potent negative reinforcement. Consequently, a comprehensive understanding of the underlying psychopathology of NSSI and the subsequent development and implementation of evidence-based psychotherapies is essential for adolescent well-being. This study aimed to comprehensively review the theoretical models and existing evidence-based psychotherapies for adolescent NSSI, thereby providing clinically applicable guidelines and outlining directions for future research.

METHODS

Psychotherapy research on adolescent NSSI is nascent, with accumulated evidence primarily concentrated on specific treatment models, such as dialectical behavior therapy (DBT) and cognitive behavioral therapy (CBT). Therefore, rather than conducting a systematic review to evaluate the efficacy of specific interventions, this study adopted a narrative review approach to broadly explore and synthesize the current understanding of the psychopathology and various therapeutic approaches for adolescent NSSI.

To comprehensively examine the relevant literature, we searched several major academic databases (PubMed, PsycINFO, Cochrane Library, and Scopus) for articles published between January 2000 and June 2025. The search strategy combined keywords related to NSSI (“non-suicidal self-injury,” “NSSI,” “self-harm”) with population terms (“adolescent,” “youth”) and various psychotherapeutic approaches (e.g., “psychotherapy,” “treatment,” “dialectical behavior therapy,” “mentalization-based treatment,” “acceptance and commitment therapy,” “cognitive behavioral therapy,” and “attachment-based family therapy”).

The following criteria were prioritized during the article selection process: 1) studies involving adolescent participants (aged 12–18 years); 2) efficacy studies of psychotherapeutic interventions addressing NSSI as a primary outcome (including randomized controlled trials [RCTs], meta-analyses, and existing systematic reviews); and 3) key theoretical studies proposing major psychopathological models of NSSI. The literature review was restricted to articles published in English or Korean. Based on the selected literature, this review synthesized and discussed the psychopathological models of adolescent NSSI as well as the theoretical background and efficacy of various treatment modalities.

RESULTS

Psychopathology of NSSI: major theoretical models

Theories explaining the onset and maintenance of NSSI can be broadly structured into models focusing on intrapersonal cognitive and emotional processes and those emphasizing interpersonal and developmental contexts.

Behavioral and cognitive-emotional framework

These perspectives focus on the intrapersonal mechanisms that precipitate and sustain self-injury, particularly difficulties with emotion regulation and maladaptive cognitive processes.

Emotion regulation theory and biosocial theory

Emotion regulation theory is the prevailing model for explaining NSSI, conceptualizing it as a maladaptive coping strategy employed to regulate overwhelming emotional distress [11,12]. When adolescents face intolerable negative affect (e.g., anxiety, anger, emptiness) and lack healthy coping skills, they experience intense emotional pressure. NSSI provides an immediate reduction in distress. This temporary relief strongly maintains the behavior through “automatic negative reinforcement” [10,13]. However, this short-term relief often triggers secondary negative emotions (e.g., shame and guilt), exacerbating internal distress and forming a vicious cycle leading to subsequent urges for self-injury [12].

Marsha Linehan’s biosocial theory contributes to our understanding of the developmental origins of emotional dysregulation [14]. According to this theory, emotion dysregulation results from the transaction between biologically based “emotional vulnerability” (high sensitivity, high reactivity, slow return to baseline) and an “invalidating environment” that persistently dismisses or punishes the individual’s emotional experiences [15]. The identification of emotion regulation failure as the core pathology of NSSI forms a direct theoretical basis for the development of DBT [16].

Cognitive-behavioral perspective and the experiential avoidance model

The cognitive-behavioral perspective understands NSSI as a sequence involving distorted cognitive appraisal of a precipitating event, resulting in negative affect and the maladaptive behavior employed to alleviate it. For instance, an adolescent may catastrophically interpret a minor conflict (cognitive distortion) and choose NSSI to cope with ensuing intense emotions. While this behavior provides short-term relief, it reinforces irrational core beliefs (e.g., “NSSI is the only solution”) in the long term [17].

The experiential avoidance model, a core concept in “third-wave CBT,” offers a particularly useful framework [17]. Experiential avoidance refers to attempts to avoid or control unwanted internal experiences such as painful thoughts or emotions. According to this model, NSSI is an extreme form of experiential avoidance in which individuals attempt to eliminate or distract themselves from internal distress by substituting it with physical pain rather than accepting the distress. The emotional cascade model elaborates on this process, proposing that rumination on negative affect amplifies emotions uncontrollably and that NSSI acts as a potent dis-traction mechanism to break this escalating emotional loop [18].

This cognitive-behavioral perspective provides a rationale for applying traditional CBT, which aims to modify automatic thoughts and core beliefs. It also forms a theoretical foundation for acceptance and commitment therapy (ACT), which directly addresses experiential avoidance mechanisms and aims to enhance psychological flexibility [19].

Functional model: four-factor model

The functional model proposed by Nock and Prinstein [20] focuses on the purpose (function) of NSSI for the individual, rather than the behavior itself. Based on the principle of operant conditioning—that behavior is maintained by its consequences—this model classifies the functions of NSSI into four types:

• Automatic-negative reinforcement: To reduces aversive internal states such as painful emotions (the most common function).

• Automatic-positive reinforcement: To generate desired sensory stimulations (e.g., relieve emotional numbness, self-soothing, or self-punishment).

• Social-negative reinforcement: To escape unwanted interpersonal situations or obligations.

• Social-positive reinforcement: To elicit desired social responses, such as attention or help from others.

The primary clinical implication of this functional perspective is that treatment strategies should vary depending on the specific function of NSSI for the individual. For example, emotion regulation skill training is crucial if adolescents’ NSSI is primarily driven by automatic reinforcement, whereas, interpersonal skills training or family interventions may be critical if NSSI primarily serves a social function. This model provides a critical theoretical basis for the development of personalized treatment plans [21].

Interpersonal, systems, and developmental framework

These perspectives emphasize the importance of the relational and developmental contexts in which NSSI occurs, and explore how external factors influence NSSI.

Attachment theory and mentalization

From the perspective of attachment theory, experiences of insecure attachment with primary caregivers serve as a fundamental vulnerability factor for NSSI [15]. Children who experience insecure attachment often fail to develop adequate regulatory capacities, increasing the risk of relying on NSSI to soothe internal distress when faced with stress during adolescence [4].

Closely related is the concept of mentalization, defined as the ability to understand and infer the mental states (thoughts, feelings, and intentions) underlying one’s own and others’ behaviors. Insecure attachment can lead to impaired mentalization capacity, resulting in deficits in the ability to cognitively process and regulate emotions [22]. Adolescents with poor mentalization skills may attempt to communicate their distress by “acting out” using their bodies, rather than understanding or verbalizing their intense emotions. This aligns with the psychodynamic perspective that views NSSI as a primitive attempt to communicate unspeakable internal pain. This perspective provides a theoretical foundation for mentalization-based treatment (MBT) [23].

Interpersonal theory

Interpersonal theory explains NSSI within a relational context, emphasizing social isolation, peer victimization, and family conflict as key factors driving and maintaining NSSI. NSSI can function as a distorted means of interpersonal communication. For adolescents who find it difficult to verbalize their distress or whose expressions have been invalidated, self-injury can be a potent nonverbal message conveying desperation (social-positive reinforcement) [24]. Conversely, it can be used to avoid unwanted interpersonal demands (social-negative reinforcement). This perspective supports the importance of treatments addressing family system dynamics, such as attachment-based family therapy (ABFT) [25] and interpersonal psychotherapy [26].

Interpersonal-psychological theory of suicide

Thomas Joiner’s interpersonal-psychological theory of suicide (IPTS) elaborates on the lethal relationship between NSSI and suicide rather than the psychopathology of NSSI. IPTS posits that the desire for suicide arises from “thwarted belongingness” and “perceived burdensomeness” [27]. In this theory, NSSI is considered a key mechanism for developing the “acquired capability for suicide”—the ability to enact lethal self-injury. Repeated exposure to painful self-injurious behaviors increases pain tolerance and diminishes the fear of death (habituation), consequently increasing the capability to attempt suicide [28].

Integrative understanding of theoretical models

The theoretical models discussed above are not mutually exclusive and require integration for a multi-layered understanding of the complex phenomena of NSSI. Biosocial and attachment theories explain the origin of the developmental vulnerabilities that predispose individuals to NSSI. Emotion regulation and interpersonal theories (including mentalization) illustrate the core deficits (emotion dysregulation, impaired mentalization, and interpersonal disconnection) resulting from these vulnerabilities. Finally, the functional and cognitive-behavioral perspectives specifically explain how these deficits manifest as NSSI behavior and through what mechanisms (reinforcement and experiential avoidance) the behavior is maintained. This integrative understanding provides far more sophisticated clinical insights than a single model, thus facilitating the development of more effective and personalized treatment plans.

Practice and efficacy of evidence-based psychotherapies

Various theoretical models of NSSI have led to the development of specific psychotherapies. In clinical practice, theory-driven treatments are applied to alleviate adolescent distress and their efficacy is evaluated through rigorous scientific validation. This section examines the core principles of major psychotherapies and critically reviews their effectiveness, focusing on the highest levels of evidence such as Cochrane reviews.

Treatment targeting emotion dysregulation: dialectical behavior therapy

Currently, DBT has the strongest and most consistent empirical evidence for reducing self-injurious behaviors in adolescents [29]. DBT is rooted in biosocial theory and posits that chronic emotional dysregulation is the core pathology of NSSI [11]. The ultimate goal is to “build a life worth living,” focusing on replacing self-destructive behaviors such as NSSI with adaptive coping skills [30].

The central principle of DBT is “dialectics”: the balance and integration of the opposing tenets of “acceptance” and “change” [16]. Therapists nonjudgmentally accept and validate adolescents’ current distress, while simultaneously emphasizing the necessity of behavioral change. This dialectical stance prevents therapeutic impasses and helps sustain adolescents’ motivation for change [31]. DBT is structured around the systematic teaching of four core skill modules [32,33].

• Mindfulness: The foundation of all skills, cultivating the ability to notice thoughts and emotions, and urging non-judgment in the present moment. This is crucial for preventing impulsive self-harm by creating a “pause” between emotional impulse and action.

• Distress tolerance: Teaches skills to survive intense emotional crises without worsening the situation. Includes “TIPP skills” (Temperature, Intense exercise, Paced breathing, and Paired muscle relaxation), distraction, and self-soothing, directly replacing the crisis management function of NSSI.

• Emotion regulation: Learning to recognize, understand, and modulate the intensity of unwanted emotions. Enhances the ability to cope effectively without being overwhelmed, through techniques such as “Opposite Action.”

• Interpersonal effectiveness: Learning skills to effectively make requests, refuse demands, resolve conflicts, and maintain relationships. This helps replace the interpersonal functions of the NSSI.

The efficacy of DBT is supported by the highest level of evidence. A 2021 systematic review from Cochrane concluded there is “high-certainty” evidence that DBT for adolescents is effective compared to treatment as usual (TAU) in reducing the repetition of self-harm (odds ratio [OR]=0.46, 95% confidence interval [CI]: 0.26–0.82) [34]. This represents the strongest recommendation level among NSSI treatments to date. Multiple meta-analyses have corroborated these findings [32,35]. Owing to such consistent and robust evidence, DBT is currently recognized as the “gold standard” treatment for adolescent NSSI.

Treatment targeting impairments in interpersonal relations and self-understanding: MBT

MBT is grounded in attachment and psychodynamic theories developed by Peter Fonagy and Anthony Bateman. The core assumption of MBT is that severe psychopathology, such as NSSI, stems from the breakdown of “mentalizing” capacity. Healthy mentalizing develops within secure attachment relationships and is essential for emotion regulation and the formation of meaningful relationships [23]. According to the MBT model, individuals with fragile mentalizing capacity temporarily lose this ability, particularly under interpersonal stress, when the attachment system is activated. When mentalization collapses, individuals feel confused about their internal experiences and are prone to misinterpret others’ actions as threatening. To resolve the overwhelming psychological pain experienced in this “non-mentalizing” state, they resort to NSSI, which is a concrete and physical act [36].

The therapeutic goal of MBT is to restore and strengthen the patient’s mentalizing capacity within a safe and trusting therapeutic relationship. The therapist adopts a “not-knowing stance,” exploring the patient’s inner world with curiosity. The process helps patients better understand the connection between their feelings, thoughts, and actions and supports them in inferring others’ mental states more accurately, thereby reducing interpersonal misunderstandings and conflicts [37].

Evidence for the effectiveness of MBT is far less established than that for DBT, with mixed findings. A pioneering RCT by Rossouw and Fonagy [38] provided important positive evidence. In this study, MBT for adolescents (MBT-A) significantly reduced self-harm behaviors and depressive symptoms more than TAU over 12 months, and these effects were mediated by improvements in mentalizing capacity. However, despite these positive findings, subsequent higher-level evidence requires cautious interpretation. The 2021 Cochrane review, analyzing two RCTs on MBT-A, rated the evidence for reducing self-harm repetition as having “very low-certainty” (OR=0.70, 95% CI: 0.06–8.46) [34]. This discrepancy between the positive results of an influential early RCT and cau-tious appraisal of the highest-level systematic review clearly indicates that the efficacy of MBT-A has not yet been consistently demonstrated. Therefore, while MBT-A is theoretically compelling, rigorous replication through high-quality large-scale RCTs is urgently required to establish its efficacy [39].

Cognitive-behavioral approaches: from traditional CBT to third-wave therapies

CBT encompasses a broad spectrum of interventions based on the premise that psychological distress and maladaptive behaviors, such as NSSI, are maintained by distorted cognitive processes and learned behavioral patterns. These approaches have evolved over time, leading to distinct waves of therapy focusing on different mechanisms of change [40].

Traditional cognitive behavioral therapy

Traditional (or second-wave) CBT focuses on identifying and modifying cognitive distortions (e.g., catastrophizing and dichotomous thinking) that precipitate intense negative affect, leading to NSSI [41]. The primary goal is to help adolescents recognize the connection between triggering events, their interpretation of those events, and their subsequent behavioral responses. Interventions typically include functional analysis, cognitive restructuring (challenging irrational beliefs), problem-solving training, and development of a repertoire of alternative coping behaviors [42].

An evidence base for CBT in treating adolescent NSSI has been established, indicating its effectiveness compared with TAU. However, the evidence is generally less robust than that for DBT. The 2021 Cochrane review found that while individual CBT may reduce the repetition of self-harm compared with TAU, the certainty of the evidence was “low” (OR=0.93, 95% CI: 0.12–7.24), indicating considerable uncertainty regarding the magnitude of the effect [34].

Third-wave CBT: ACT and mindfulness-based interventions

“Third-wave” CBT approaches represent an evolution of cognitive-behavioral traditions. Rather than focusing on changing the content of painful thoughts and emotions, these approaches emphasize changing individuals’ relationship with them [43]. They directly address “experiential avoidance,” the attempt to control or eliminate unwanted internal experiences, which is often counterproductive and is viewed as a core maintenance mechanism of NSSI [44].

ACT aims to increase psychological flexibility—the ability to be present with internal experiences while engaging in behaviors aligned with personal values [19]. ACT utilizes “acceptance” and “cognitive defusion” (distancing from thoughts) techniques, shifting the focus from symptom reduction to “committed action” in service of “values” [45]. Despite its compelling theoretical rationale, empirical evidence for ACT in the treatment of adolescent NSSI remains in its nascent stages. The existing literature primarily comprises small-scale or retrospective studies and case reports, with a notable scarcity of large-scale RCTs. Therefore, rigorous RCTs are urgently needed to validate its efficacy for this population [46,47].

Mindfulness-based interventions (MBIs), such as mindfulness-based stress reduction and mindfulness-based cognitive therapy, train individuals to acquire non-judgmental awareness of the present moment. In the context of NSSI, mindfulness is hypothesized to create a psychological space in which an individual can observe the urge to self-injure without automatically reacting, thereby allowing the intensity of the urge to diminish naturally [48]. While mindfulness is a foundational component of DBT and much of the evidence for its utility is concentrated within DBT-based research, large-scale RCTs evaluating the direct effects of standalone MBI programs on adolescent NSSI are scarce [48].

Targeting family systems and attachment: ABFT

While the previously discussed therapies (DBT, MBT, and CBT/ACT) primarily target individual capacities (e.g., emotion regulation, mentalization, and cognitive skills), adolescent NSSI often arises and is maintained within interpersonal and family contexts. As highlighted by attachment and interpersonal theories, invalidation or insecure parent–child attachment during family conflicts are prominent factors, making interventions that target the family system even more crucial [49].

ABFT is a manualized and empirically supported treatment designed to address adolescent depression and suicidality by targeting the quality of family relationships. Grounded in attachment theory, ABFT posits that unresolved “attachment ruptures” (e.g., betrayal, neglect, chronic conflict) impair the adolescent’s ability to use the family as a secure base for emotion regulation, leading to distress and maladaptive coping behaviors such as NSSI [25,50].

The primary goal of ABFT is not merely behavior reduction, but the repair of these attachment ruptures and restoration of the parent–child bond. ABFT uses a structured five-task framework:

• Reframing the therapy focus to interpersonal relationships.

• Building an alliance with the adolescent.

• Building an alliance with the parents.

• Facilitating conversations to resolve attachment ruptures (corrective attachment experiences).

• Promoting autonomy and competency in the adolescent.

By strengthening attachment relationships, ABFT seeks to enhance adolescents’ capacity for co-regulation in distress. ABFT has established strong evidence for reducing suicidal ideation and depressive symptoms in adolescents [51,52]. However, research specifically evaluating its efficacy for NSSI is still emerging. While the theoretical rationale is compelling, particularly for adolescents, for whom family dynamics are a major maintenance factor, rigorous RCTs are needed to establish its efficacy, specifically for NSSI reduction [53].

Synthesis of evidence and clinical implications: the challenge of personalized treatment

Synthesizing the evidence across different modalities, a clear hierarchy emerges regarding the certainty of the effects for reducing adolescent NSSI. DBT currently holds the strongest empirical foundation and is supported by high-certainty evidence. Traditional CBT demonstrates effectiveness, albeit with low-certainty evidence; whereas, the evidence base for MBT, ACT, and ABFT remains preliminary or uncertain, specifically for NSSI outcomes (Table 1) [34]. Table 2 summarizes the quantitative results from key systematic reviews and pivotal trials underpinning this evidence synthesis.

Table 1.

Summary of evidence-based psychotherapies for adolescent NSSI

Psychotherapy	Theoretical foundation(s)	Core mechanism(s) targeted	Evidence level for adolescent NSSI*
Dialectical behavior therapy	Biosocial theory, emotion regulation theory	Chronic emotion dysregulation Skills deficits (mindfulness, distress tolerance, emotion regulation, interpersonal effectiveness)	High-certainty
Mentalization-based treatment	Attachment theory, psychodynamic theory	Impaired mentalization capacity (difficulty understanding self/others’ mental states) Interpersonal misunderstanding under stress	Very low-certainty
Cognitive behavioral therapy (traditional)	Cognitive-behavioral model	Cognitive distortions (e.g., catastrophizing) Maladaptive learned behavioral patterns	Low-certainty
Acceptance and commitment therapy	Experiential avoidance model (third-wave CBT)	Experiential avoidance Psychological inflexibility (fusion with thoughts, lack of values clarity)	Preliminary
Mindfulness-based interventions	Mindfulness principles (third-wave CBT)	Automatic reactivity to urges and distress Lack of present-moment awareness	Preliminary
Attachment-based family therapy	Attachment theory, interpersonal/ systems theory	Attachment ruptures (unresolved family conflict/ invalidation) Impaired capacity for co-regulation within the family system	Preliminary

*evidence certainty levels (high, low, very low) regarding the reduction of self-harm repetition were primarily based on a synthesis from the Cochrane review (Witt et al. [34], 2021). “Preliminary/Emerging” indicates a current lack of sufficient high-quality evidence specific to adolescent NSSI outcomes. CBT, cognitive behavioral therapy; NSSI, non-suicidal self-injury.

Table 2.

Key studies for psychotherapeutic interventions for adolescent NSSI

Study	Design	Interventions vs. comparators	Key findings
Witt et al. (2021) [34]	Cochrane SR/MA (of RCTs)	Specific psychotherapies vs. TAU/E-TAU	Outcome: repetition of NSSI (OR<1 favors I) DBT vs. C: OR=0.46 (95% CI: 0.26 to 0.82) CBT vs. C: OR=0.93 (95% CI: 0.12 to 7.24) MBT vs. C: OR=0.70 (95% CI: 0.06 to 8.46)
Chen et al. (2025) [35]	SR/NMA (of RCTs)	Specific psychotherapies vs. TAU	Outcome: frequency of NSSI (OR<1 favors first listed therapy) DBT vs. C: OR=0.14 (95% CI: 0.04 to 0.47) MBT vs. C: OR=0.26 (95% CI: 0.07 to 1.00) CBT vs. C: OR=1.20 (95% CI: 0.46 to 3.17)
		Head-to-head comparison	CBT vs. DBT: OR=8.38 (95% CI: 2.14 to 32.91) DBT vs. MBT: OR=0.55 (95% CI: 0.09 to 3.32) CBT vs. MBT: OR=4.65 (95% CI: 0.89 to 24.45)
Bahji et al. (2021) [39]	SR/NMA (of RCTs)	Specific psychotherapies vs. TAU	Outcome: reductions in NSSI (OR<1 favors I) DBT vs. C: OR=0.28 (95% CI: 0.12 to 0.64) (at end of treatment) MBT vs. C: OR=0.38 (95% CI: 0.15 to 0.97) (at end of follow-up)
Kothgassner et al. (2021) [32]	SR/MA (of RCTs, CCTs, and pre-post)	DBT vs. TAU/E-TAU	Outcome: reductions in NSSI (Hedges’ g negative value favors I) DBT vs. C: g=-0.44 (95% CI: -0.81 to -0.07)
Mehlum et al. (2014) [29]	RCT (n=77)	DBT vs. EUC (19 weeks)	Outcome: NSSI frequency DBT vs. C: superiority
Rossouw and Fonagy (2012) [38]	RCT (n=80)	MBT vs. TAU (12 months)	Outcome: risk-taking and self-harm inventory MBT vs. C: superiority
Labelle et al. (2015) [42]	SR/MA (of RCTs and CCTs)	CB treatments (CBT/DBT) vs. TAU	Outcome: reductions in NSSI (Hedges’ g negative value favors I) CB vs. C: g=-0.27 (95% CI: -0.38 to -0.17)
Yuan et al. (2024) [46]	CCT (n=72)	ACT vs. TAU (12 weeks)	Outcome: adolescent nonsuicidal self injury questionnaire ACT vs. C: superiority

ACT, acceptance and commitment therapy; C, comparator; CB, cognitive behavioral; CBT, cognitive behavioral therapy; CCT, controlled clinical trial; CI, confidence interval; DBT, dialectical behavior therapy; E-TAU, enhanced TAU; EUC, enhanced usual care; I, intervention; MA, meta-analysis; MBT, mentalization-based treatment; NMA, network meta-analysis; NSSI, non-suicidal self-injury; OR, odds ratio; RCT, randomized controlled trial; SR, systematic review; TAU, treatment as usual.

This hierarchy presents a significant clinical challenge: the potential for “treatment-mechanism mismatch.” While evidence-based practice prioritizes the most validated treatments (i.e., DBT), theoretical models suggest that the optimal treatment should align with the underlying mechanisms driving behavior [54]. For instance, an adolescent whose NSSI is primarily driven by severe attachment ruptures and family conflict might theoretically benefit more from ABFT than DBT, which focuses on individual skills training. Similarly, MBT may be more suitable for those whose primary deficit is in understanding interpersonal dynamics (impaired mentalization). However, the current lack of robust evidence for ABFT and MBT creates a dilemma for clinicians aiming to provide personalized care.

This dilemma highlights the necessity of moving beyond the question “Which treatment is effective?” to a more nuanced inquiry: “What works for whom, and how?” Furthermore, concepts emerging from different traditions can offer integrative principles. For example, “psychological flexibility” (ACT) may represent a higher-order mechanism involving specific skills such as distress tolerance (DBT). The immediate implication for the field is the need to shift research focus from validating specific “branded” therapies toward identifying and strengthening these core change mechanisms across different approaches.

DISCUSSION

Critical assessment and limitations of the current treatment landscape

Research on psychotherapy for adolescent NSSI has advanced significantly, yielding validated treatment models. A synthesis of accumulated evidence indicates that the treatment landscape is dominated by DBT. Because this intervention is supported by “high-certainty” evidence, DBT has been established as the current treatment of choice. However, despite these advances, current research and the clinical landscape face several critical limitations that must be addressed to improve outcomes.

First, the methodological limitations inherent to this narrative review must be acknowledged. Unlike a systematic review, this synthesis did not adhere to a predefined and rigorous protocol for literature search and selection, which introduces the potential for selection bias. Specifically, established therapies with a large volume of published research, such as DBT, may be overrepresented, potentially leading to an overestimation of their relative efficacy. Conversely, emerging therapies with nascent evidence bases (e.g., ACT and ABFT for NSSI) may be underrepresented, leading to an underestimation of their potential utility.

Second, validated alternatives are scarce. Empirical evidence for other theoretically promising treatments, such as MBT, ACT, and ABFT, remains insufficient or preliminary for NSSI outcomes. This severely restricts the availability of validated options that clinicians can select based on individual patient characteristics or mechanisms, thus exacerbating the challenge of treatment mechanism mismatches.

Finally, the research-practice gap remains wide. Even evidence-based treatments such as DBT exhibit low accessibility and dissemination in community mental health settings owing to their complexity and resource intensity (e.g., extensive specialized training requirements). This challenge has resulted in many adolescents being unable to access effective care, highlighting a systemic failure to translate scientific findings into real-world impacts.

Another limitation is the increasing complexity of clinical presentations. Adolescent NSSI is often multifactorial and involves comorbidities and diverse mechanisms that rarely fit into a single theoretical model. This heterogeneity necessitates a tailored, integrated approach. There is a growing need to explore hybrid models that systematically incorporate core concepts and principles from various evidence-based treatments (e.g., integrating DBT skills with MBT’s relational focus) to address the multifaceted nature of these complex cases.

Promising future directions for treatment and research

To overcome these limitations and improve the efficacy of adolescent NSSI treatment, innovation in treatment models and refinement of research methodologies must proceed concurrently.

Directions for innovation in treatment models

• Need for empirical validation of theoretically promising alternative therapies: the limitations of DBT, including non-response among a substantial number of adolescents, necessitate the exploration of new therapeutic models targeting different core pathological mechanisms. While theoretically compelling alternatives such as ACT, ABFT, and MBT have been proposed, empirical evidence for treating adolescent NSSI remains insufficient. These therapies are designed to address specific mechanisms, such as experiential avoidance (ACT), attachment ruptures (ABFT), or impaired mentalization (MBT). However, large-scale RCTs are urgently required to validate their efficacy in reducing NSSI. Therefore, future research should focus on rigorously validating the clinical effectiveness of these models to expand the options available for personalized treatment.

• Implementation of the stepped-care model: Given the acute shortage of highly skilled clinicians and therapists, which invariably limits patient access to specialized treatments such as DBT, the most pragmatic approach to optimizing resource allocation and increasing treatment accessibility is the implementation of a stepped-care model. This model initiates treatment with the lowest intensity and least intrusive intervention, rather than providing high-intensity treatment to all patients. For example, Step 1 may provide universal school-based prevention or low-intensity interventions using digital technology (e.g., smartphone apps). Non-responders are then “stepped up” to Step 2 (e.g., brief group therapy), and only high-risk individuals who do not show improvement are referred to Step 3 (e.g., high-intensity specialized treatment such as DBT). This system maximizes efficiency and equity by ensuring minimal support for the majority while concentrating costly, intensive treatments on those with the greatest need, thereby providing a solution for the right-siting of patient care.

Challenges in refining research methodology

However, rigorous psychotherapy research has inherent difficulties. The establishment of causality is often complicated by numerous confounding factors, including patient characteristics, therapist variables (e.g., competence and allegiance effects), and treatment expectations. Furthermore, the field is susceptible to inherent biases such as publication, funding, and participant selection. Future research should employ more sophisticated methodological designs and analyses to address these issues.

• Head-to-head RCTs: A primary objective for future research is to directly compare currently promising treatments. Large-scale, multi-center RCTs (e.g., “DBT vs. MBT,” “DBT vs. ACT”) are necessary to validate the relative efficacy and cost-effectiveness of these treatments. This is essential to establish clear evidence-based guidelines on which treatment should be prioritized.

• Strengthening mechanism research: Research must transcend the question of what works, to elucidate for whom, why, and how effective an intervention is. This requires sophisticated mediation analysis to investigate the underlying mechanisms of change. For example, studies should seek to verify whether the therapeutic effect of DBT is mediated by improvements in emotion regulation skills, or whether the efficacy of ACT is attributable to enhanced psychological flexibility. Identifying the “active ingredients” in a therapy provides a theoretical foundation for developing potent and efficient interventions.

• Subgroup research for personalized treatment: NSSI is a clinically heterogeneous phenomenon. Consequently, moderation analyses are required to evaluate the efficacy of interventions for specific subgroups. Research should aim to identify which treatments confer superior efficacy in populations defined by distinct characteristics such as the presence of comorbidities (e.g., posttraumatic stress disorder and major depressive disorder) or the primary function of self-injury (e.g., social versus automatic reinforcement). This line of inquiry is fundamental to advancing the goal of precision psychiatry, that is, the delivery of optimized treatments tailored to the individual.

Thus, the future research paradigm must shift from “brand-centric” to “mechanism-centric.” Rather than focusing on DBT or ACT treatment packages, a modular approach is required—identifying core change mechanisms (e.g., distress tolerance skills, mentalization capacity, psychological flexibility) and delivering them in combinations tailored to the patient’s specific functional deficits. Furthermore, given the high prevalence and limited number of specialists, a public health approach such as the stepped-care model is essential rather than optional. Only through these sophisticated and systematic efforts can the complex challenges of adolescent NSSI be effectively addressed.

CONCLUSION

Adolescent NSSI is an expression of severe emotional distress and a critical predictor of future suicidal behavior. Therefore, systematic evidence-based therapeutic approaches grounded in theoretical models are imperative. This review synthesizing the current research and showed that DBT holds the strongest and most definitive evidence for reducing adolescent self-harm and occupies a central position in current clinical guidelines.

However, DBT is not a universal solution. The future of treatment must move beyond demonstrating the superiority of specific models toward personalization and integration. This requires prioritizing a precise functional assessment to determine the “function” that NSSI serves for the individual. Based on this assessment, efforts must focus on flexibly integrating and optimizing the core “change mechanisms” from various models—leveraging not only DBT’s robust skills training but also the relational insights of MBT, psychological flexibility enhancement of ACT, and systemic approach of ABFT.

Ultimately, the goal is not the uniform application of a specific therapy but the provision of the most effective combination of therapeutic elements tailored to the unique needs of each adolescent in distress. This precise and integrative approach represents the most promising path for helping adolescents break free from the cycle of self-harm and rebuild “a life worth living.”