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. Author manuscript; available in PMC: 2018 Apr 1.
Published in final edited form as: J Obsessive Compuls Relat Disord. 2017 Mar 4;13:30–34. doi: 10.1016/j.jocrd.2017.02.004

Clarifying the Relationship between Trichotillomania and Anxiety

Jennifer R Alexander a, David C Houghton b, Michael P Twohig c, Martin E Franklin d, Stephen M Saunders a, Angela M Neal-Barnett e, Scott N Compton f, Douglas W Woods a,✉
PMCID: PMC5628622  NIHMSID: NIHMS863476  PMID: 28989859

Abstract

Although research has consistently linked unidimensional anxiety with Trichotillomania (TTM) severity, the relationships between TTM severity and anxiety dimensions (i.e., cognitive and somatic anxiety) are unknown. This knowledge gap limits current TTM conceptualization and treatment. The current study examined these relationships with data collected from ninety-one adults who participated in a randomized clinical trial for TTM treatment. To examine whether the Beck Anxiety Inventory (BAI; Beck, Epstein, Brown, & Steer, 1988) could be used to measure multidimensional anxiety in TTM samples, we conducted a factor analysis. Results showed four emergent factors, including a cognitive factor and three somatic factors (neurophysiological, autonomic, and panic). Based on prior research, it was hypothesized that TTM severity would be related to the cognitive anxiety dimension and that psychological inflexibility would mediate the association. Hypotheses were not made regarding the relationship between TTM severity and somatic anxiety. Regression analyses indicated that only cognitive dimensions of anxiety predicted TTM severity and that psychological inflexibility mediated this relationship. Implications for the conceptualization and treatment of TTM are discussed.

Keywords: Trichotillomania, cognitive anxiety, somatic anxiety, psychological inflexibility

Trichotillomania (TTM; also referred to as Hair Pulling Disorder) is a debilitating condition defined by recurrent hair pulling despite repeated attempts to stop (American Psychiatric Association [APA], 2013). Based on research suggesting that negative affect, particularly anxiety, contributes to disorder duration and severity (Christenson, Mackenzie, & Mitchell, 1991; Christenson & Mansueto, 1999; Hajcak, Franklin, Simons, & Keuthen, 2006; Mansueto, Stemberger, Thomas, & Golomb, 1997; Roberts, O’Connor, & Bélanger, 2013; Stanley, Borden, Bell, & Wagner, 1994), various TTM treatment models augment traditionally effective behavioral treatments (e.g., Habit Reversal Therapy; Azrin & Nunn, 1973) with anxiety-targeting techniques. However, different TTM treatment models target different anxiety components. For instance, comprehensive behavioral treatment models tend to target physiological symptoms of anxiety via techniques like deep breathing (Azrin, Nunn, & Frantz, 1980); cognitive-behavioral treatment (CBT) models target anxiogenic cognitions and feelings via techniques like cognitive restructuring (Lerner, Franklin, Meadows, Hembree, & Foa, 1999); and third-wave behavioral treatment models target meta-cognitions about experiencing anxiety via techniques like mindfulness (Keuthen et al., 2010; Woods & Twohig, 2008). Unfortunately, there is currently little empirical basis for targeting any one component of anxiety over another, as the specific nature of the relationship between anxiety and TTM is unknown. Developing a better understanding of how the various components of anxiety relate to TTM is necessary for developing a better understanding of the disorder and its treatment.

TTM research has predominantly treated anxiety as a unidimensional construct (e.g., Diefenbach, Mouton-Odum, & Stanley, 2002; Diefenbach, Tolin, Hannan, Crocetto, & Worhunsky, 2005; Diefenbach, Tolin, Meunier, & Worhunsky, 2008; Duke, Bodzin, Tavers, Geffken, & Storch, 2009; Houghton et al., 2014; Shusterman, Feld, Baer, & Keuthen, 2009; Stanley et al., 1994). However, anxiety researchers recognize anxiety as a multidimensional construct consisting of cognitive (sometimes referred to as subjective anxiety; e.g., fear and worry) and somatic (e.g., physiological arousal and panic) dimensions (Clark & Watson, 1991; Nitschke, Heller, Imig, McDonald, & Miller, 2001; Ree, French, MacLeod, & Locke, 2008). Conceptualizing anxiety in such a way is clinically meaningful, as research suggests that cognitive and somatic anxiety symptoms respond best to different treatments (Schwartz, Davidson, & Goleman, 1978; Tamaren, Carney, & Allen, 1985). Accordingly, to develop treatments that effectively target anxiety associated with TTM, it is important to understand the relationships between the different dimensions of anxiety and TTM severity.

The few studies that have examined the relationships between TTM severity and the cognitive and somatic anxiety dimensions have not been conclusive. Some evidence suggests that TTM severity is related to aspects of cognitive anxiety, such as worry (Hajcak et al., 2006), and other evidence suggests TTM is related to fear of negative evaluation (Norberg, Wetterneck, Woods, & Conelea, 2007). Still, other evidence suggests that while TTM-affected persons demonstrate higher levels of cognitive and somatic anxiety than unaffected persons, TTM severity may not be related to either anxiety dimension (Wetterneck, Lee, Flessner, Leonard, & Woods, 2016). However, this study was limited by a small sample size that may have precluded power to detect such relationships. Overall, research appears to suggest that TTM severity may be related to cognitive aspects of anxiety, but it is unclear whether TTM severity is related to somatic anxiety.

In addition to understanding how particular aspects of anxiety are related to TTM symptoms, researchers have also examined how anxiety symptoms are perceived and acted upon by persons with TTM. To this end, a growing body of research focuses on the role of psychological inflexibility (i.e., one’s propensity to prioritize the mitigation of undesirable private experiences over the continuation of adaptive goal pursuits; Bond et al., 2011). For example, studies have found that psychological inflexibility mediates the relationship between hair pulling severity and both unidimensional measures of anxiety (Houghton et al., 2014) as well as some of the cognitive aspects of anxiety (i.e., apprehension/anxious thoughts about being negatively evaluated by others; Norberg et al., 2007). However, it is unclear whether psychological inflexibility mediates the relationship between TTM severity and the broader cognitive anxiety dimension. Further, no study has examined whether psychological inflexibility mediates the relationship between TTM severity and somatic aspects of anxiety.

The current study was intended to explore further the anxiety-TTM relationship. Using the same data set utilized by Houghton et al. (2014), the current study examined whether TTM severity (assessed via self-report and clinician rating) is differentially related to different anxiety dimensions (i.e., cognitive and somatic). In addition, the current study examined whether TTM-specific psychological inflexibility mediated the relationship between the two anxiety dimensions and TTM severity.

Based on the findings of Hajcak et al. (2006) and Norberg et al. (2007), we hypothesized that the cognitive domain of anxiety would be significantly related to TTM severity. In addition, consistent with findings from Norberg et al. (2007), we hypothesized that TTM-specific psychological inflexibility would mediate the relationship between cognitive anxiety and TTM severity. Based on prior research showing no relationship between somatic forms of anxiety and TTM (Wetterneck et al., 2016), we did not anticipate finding an association between TTM severity and the somatic dimension of anxiety in the current study.

Method

Participants

Data were collected as part of a randomized, clinical trial for TTM treatment. Information about the sample and recruitment can be found in (Houghton et al., 2016).

Ninety-one participants (92% female; 8% male) were included in the current study. Seventy-six participants identified as European American (84%), eleven identified as African American (12%), one identified as Asian American (1%), and three identified as multiracial or did not disclose their race (3%). In addition, one participant identified as Hispanic or Latino (1%). Participants had a mean age of 35.04 years (SD = 12.68).

Measures

The Beck Anxiety Inventory (BAI; Beck, Epstein, Brown, & Steer, 1988) is a 21-item self-report measure of clinical anxiety that assesses both somatic and cognitive symptoms of anxiety. Each item on the BAI is ranked on a 0–3 scale. Thus, raw scores range from 0–63, with higher scores indicating higher levels of anxiety. Although the BAI total score is frequently used in research, several studies suggest that the BAI consists of multiple factors. Two studies (Beck & Steer, 1991; Steer, Ranieri, Beck, & Clark, 1993) exploring the factor structure of the BAI in clinically anxious samples concluded that the BAI consists of four factors: subjective anxiety, neurophysiological anxiety, autonomic anxiety, and panic anxiety. These same researchers hypothesized that raw scores on the subjective anxiety factor assessed cognitive anxiety and raw scores on the neurophysiological, autonomic, and panic anxiety factors assessed somatic anxiety (Steer, Rissmiller, Ranieri, & Beck, 1993).

The Massachusetts General Hospital Hairpulling Scale (MGH-HS; Keuthen et al., 1995) is a seven-item self-report measure of hair pulling and hair pulling urge severity. Total scores on the MGH-HS range from 0–28, and higher scores indicate greater hair pulling severity. Research suggests the MGH-HS is reliable and valid in TTM samples (Keuthen et al., 2007; O’Sullivan et al., 1995).

The NIMH-Trichotillomania Severity Scale (NIMH-TSS; Swedo, Rapoport, Leonard, Lenane, & Cheslow, 1989) is a five-item clinician rated measure of TTM severity. Total scores range from 0–25, with higher scores indicating greater TTM severity. Research suggests the NIMH-TSS demonstrates acceptable reliability and validity in TTM samples (Diefenbach, Tolin, Crocetto, Maltby, & Hannan, 2005; Swedo et al., 1989).

The Acceptance and Action Questionnaire Trichotillomania (AAQ-TTM; Houghton et al., 2014) is a nine-item self-report measure of TTM-specific psychological inflexibility. Higher scores indicate greater TTM-specific psychological flexibility (i.e., greater ability to resist hair pulling when distressed), while lower scores indicate greater TTM-specific psychological inflexibility. Preliminary research suggests that the AAQ-TTM has satisfactory validity and reliability in clinical TTM samples (Houghton et al., 2014).

Procedure

Information about the procedures used in the randomized, controlled trial can be found in Houghton et al. (2016). Only data from the baseline visit were used. During the baseline visit, participants completed the BAI, MGH-HS, and AAQ-TTM, and they also were evaluated with the NIMH-TSS.

Results

BAI Factor Analysis

The factor structure of the BAI has never been examined in a TTM sample. Accordingly, to examine whether the BAI could be used to measure dimensional anxiety in a TTM sample, an exploratory factor analysis (EFA) of the current sample’s BAI was conducted and the resulting BAI factor structure was compared with the BAI factor structures observed by Beck and Steer (1991) and Steer, Ranieri et al. (1993) in clinically anxious samples.

Initial analysis of the current sample’s BAI data [Kaiser-Meyer-Olkin (KMO = .85) and Bartlett’s Test of Sphericity (χ2 = 1112.26, p < .001)] indicated that the data were suitable for factor analysis. Therefore, the items of the BAI were subjected to principal axis factoring and a varimax rotation in IBM SPSS Version 20. Factors with eigenvalues greater than one were considered valid (Kaiser, 1960). Using this criterion, four factors emerged from this analysis. Items were deemed to belong to a factor when they had item-factor loadings of .40 or higher (Hair, Black, Anderson, & Tatham, 1995). Table 1 displays the specific item-factor loadings.

Table 1.

Item-Factor Loadings Resulting from Exploratory Factor Analysis Varimax Rotation

Items Factor 1 Loadings Factor 2 Loadings Factor 3 Loadings Factor 4 Loadings Communalities
Neurophysiological Anxiety
1 Numbness or tingling .41 .08 .22 .10 .38
3 Wobbliness in legs .56 .17 .29 .54 .70
6 Dizzy or lightheaded .82 .14 .05 .09 .81
7 Heart pounding/racing .61 .19 .29 −.05 .55
8 Unsteady .73 .26 .18 .17 .78
12 Hands trembling .54 .29 .24 .23 .65
13 Shaky/unsteady .76 .27 .19 .16 .81
15 Difficulty in breathing .54 .11 .26 .25 .55
19 Faint/lightheaded .75 .80
Cognitive Anxiety
4 Unable to relax .30 .51 .40 −.13 .55
5 Fear of worst happening .21 .71 .29 .10 .65
9 Terrified or afraid .35 .67 .01 .23 .69
10 Nervous .32 .51 .22 −.10 .51
14 Fear of losing control .38 .52 .29 .05 .61
16 Fear of dying −.08 .54 .26 .42 .55
17 Scared .19 .81 .06 .19 .70
Autonomic Anxiety
2 Feeling hot .24 .14 .81 .20 .71
20 Face flushed .33 .27 .47 .03 .53
21 Hot/cold sweats .16 .25 .72 .23 .70
Panic Anxiety
11 Feeling of choking .24 .13 .14 .76 .59
Other Items
18 Indigestion .32 .18 .21 .04 .33
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Note. Bolded item-factor loadings exceeded the cutoff (.40) for item inclusion.

The BAI factor structure that emerged from the current EFA were similar to the structures obtained by Beck and Steer (1991) and Steer, Ranieri et al. (1993); thus, it was determined that the BAI could be used to measure dimensional anxiety in the current sample. Further, the BAI factors observed in the current analysis were named after those observed by Beck and Steer (1991) and Steer, Ranieri et al. (1993). The first factor, named the “neurophysiological anxiety” factor, had an eigenvalue of 8.61, accounted for 41.00% of the variance, and consisted of nine items. The second factor resembled Beck and Steer’s (1991) and Steer, Ranieri et al.’s (1993) subjective anxiety factor; however, in the current analysis this factor was named the “cognitive anxiety” factor. The cognitive anxiety factor had an eigenvalue of 1.94, accounted for 9.21% of the variance, and consisted of seven items. The third factor, named the “autonomic anxiety” factor, had an eigenvalue of 1.46, accounted for 6.96% of the variance, and consisted of four items. The final factor, named the “panic anxiety” factor, had an eigenvalue of 1.29, accounted for 6.12% of the variance, and consisted of three items. Based on categorizations articulated by Steer, Rissmiller et al. (1993) the cognitive anxiety factor was determined to represent cognitive anxiety, whereas the neurophysiological, autonomic, and panic anxiety factors were considered as 3 different indices of somatic anxiety. (Each of these somatic anxiety indices was examined independently in the current analyses.)

Factor scores were created by adding the item scores. Thus, scores could range from 0-21 on the cognitive anxiety factor, from 0–27 on the neurophysiological anxiety factor, from 0–12 on the autonomic anxiety factor, and from 0–9 on the panic anxiety factor, with higher scores indicating greater anxiety. The correlations between the four scales are shown in Table 2.

Table 2.

Pearson’s Correlations between Observed BAI Factors

Factors 1 2 3
1. Neurophysiological Anxiety -
2. Cognitive Anxiety .60** -
3. Autonomic Anxiety .59** .70** -
4. Panic Anxiety .59** .58** .55**
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**

p < .001.

Relationship between Anxiety Factors, Psychological Inflexibility, and TTM Severity

Correlational analyses were used to examine the relationship between each of the anxiety factors, hair pulling severity, and TTM-specific psychological inflexibility (see Table 3 for correlation coefficients). Results indicated that only the cognitive anxiety factor was significantly correlated with TTM severity. The cognitive, neurophysiological, and autonomic anxiety factors were correlated with TTM-specific psychological inflexibility.

Table 3.

Pearson’s Correlations between BAI Factors and Measures of TTM Severity and Psychological Inflexibility

MGH-HS NIMH-TSS AAQ-TTM
1. Neurophysiological Anxiety .11 .16 −.30**
2. Cognitive Anxiety .24* .23* −.41**
3. Autonomic Anxiety .10 .16 −.23*
4. Panic Anxiety .04 .13 −.07
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Note. AAQ-TTM = Acceptance and Action Questionnaire Trichotillomania; MGH-HS = Massachusetts General Hospital Hairpulling Scale; NIMH-TSS = National Institute of Mental Health Trichotillomania Severity Scale.

*

p < .05,

**

p ≤.001.

Because the cognitive anxiety factor was the only anxiety factor significantly correlated with TTM severity, only this relationship was explored further. The Baron and Kenny (1986) approach was used to examine whether TTM-specific psychological inflexibility mediated the relationship between cognitive anxiety and TTM severity. Results indicated that TTM-specific psychological inflexibility completely mediated the relationships between cognitive anxiety and both self-reported TTM severity and clinician-rated TTM severity. The mediation analyses are summarized in Figures 1 and 2, which display the regression coefficients.

Figure 1.

Figure 1

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Regression coefficients for the relationship between cognitive anxiety and MGH-HS as mediated by TTM-Specific experiential avoidance. MGH-HS = Massachusetts General Hospital Hairpulling Scale. *p < .05, **p≤ .001.

Figure 2.

Figure 2

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Regression coefficients for the relationship between cognitive anxiety and NIMH-TSS as mediated by TTM-Specific experiential avoidance. NIMH-TSS = National Institute of Mental Health Trichotillomania Severity Scale. *p < .05, **p ≤.001.

Discussion

Research demonstrates that anxiety is associated with TTM, but the nuances of this relationship are relatively unknown. Accordingly, we explored the relationship between dimensions of anxiety (i.e., cognitive and somatic anxiety) and TTM severity. We also explored whether psychological flexibility mediated the relationships between anxiety dimensions and TTM severity. Based on research suggesting that hair pulling severity is related to cognitive aspects of anxiety (Hajcak et al., 2006; Norberg et al., 2007) and that psychological inflexibility mediates this relationship (Norberg et al., 2007), we hypothesized that cognitive anxiety would be related to TTM severity and that TTM-specific psychological inflexibility would mediate this relationship. We also conducted analyses looking at whether somatic domains of anxiety were related to TTM severity.

To ensure that the BAI could be used to measure dimensional anxiety in the current TTM sample, we first performed an EFA of the current sample’s BAI data. The BAI factors emerging from this analysis resembled the factors found in previous research on the BAI (Beck & Steer, 1991; Steer, Ranieri et al., 1993). Consequently, we concluded that the BAI could be used to measure cognitive and somatic anxiety in the current sample. Consistent with previous hypotheses regarding these BAI factors (Steer, Rissmiller et al., 1993), the cognitive anxiety factor was used to measure cognitive anxiety and the neurophysiological, autonomic, and panic anxiety factors were used to measure somatic anxiety.

The current results confirmed the hypothesis that greater cognitive anxiety was associated with greater TTM severity, whereas the three dimensions of somatic anxiety were not associated with TTM severity. Further, the current results demonstrated that TTM-specific psychological inflexibility completely mediated the relationship between cognitive anxiety and TTM severity, suggesting that when an individual with TTM experiences cognitive anxiety, his or her pulling severity is primarily a function of his or her psychological flexibility. Individuals with greater psychological inflexibility will be significantly more likely to pull when cognitive anxiety is present, and conversely, those with greater flexibility will be able to resist pulling in the presence of cognitive anxiety.

Such findings have significant treatment implications. The current results appear to suggest that individuals who frequently experience anxiety as a trigger to TTM hair pulling should be treated with psychotherapeutic models that supplement traditional TTM behavioral therapy with techniques that primarily target cognitive anxiety (e.g., cognitive restructuring and meditation) as opposed to techniques that primarily target somatic anxiety (e.g., diaphragmatic breathing exercises, progressive muscle relaxation, and exercise; Schwartz et al., 1978; Tamaren et al., 1985). Moreover, as results suggest TTM-specific psychological inflexibility mediates the relationship between cognitive anxiety and TTM severity, the current study supports the use of TTM treatment programs that target TTM-specific psychological inflexibility, such as ACT-enhanced behavior therapy (AEBT; Woods & Twohig, 2008), or dialectical behavior therapy (Keuthen et al., 2010).

The current study did have limitations. One methodological limitation was the relatively small sample size. Nevertheless, given that TTM is a low-prevalence condition, this was a relatively large sample that was also well-characterized. An additional theoretical limitation was that the current study only considered the relationship between anxiety and TTM severity. Future research may also benefit from examining the relationship between other forms of negative affect and TTM severity.

In addition to providing further support for findings from Hajcak et al. (2006) and Norberg et al. (2007), the current study suggests that TTM severity is differentially related to anxiety dimensions. Future research should continue to explore the relationship between anxiety dimensions and other variables relevant to TTM (e.g., disorder duration, quality of life, TTM disorder-related impairment, comorbidity, etc.). Future research may also benefit from examining the relationship between TTM severity and variables related to the experience of anxiety (e.g., anxiety sensitivity, affect regulation, and neural activation).

Highlights.

  • This paper explored the nuances of the anxiety-Trichotillomania (TTM) relationship

  • TTM severity is related to cognitive, but not somatic, anxiety dimensions

  • Psychological inflexibility mediates the link between TTM and cognitive anxiety

  • TTM treatments should target cognitive anxiety and psychological inflexibility

Footnotes

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