Since the turn of the century, the term “serious mental illness” has become increasingly popular (Kessler et al., 2003) to denote illnesses—usually schizophrenia and bipolar disorder—that have grave consequences and cause great hardship. This raises the question of what constitutes a non-severe or mild mental disorder, one that across all its manifestations does not have serious consequences. At first glance, body-focused repetitive behaviors (BFRBs), which are characterized by habitual manipulation of the outer shell of one’s body in a harmful way (e.g., nail biting, trichotillomania), appear a good candidate for a “mild mental disorder” as BFRBs are common habits that often result in only minor impairment and some forms seem to represent epiphenomena arising from stress and certain somatic risk factors (e.g., acne for skin picking). On closer look, however, the view that BFRBs are a minor problem is untenable. There are documented cases of BFRBs resulting in life-threatening somatic sequelae (e.g., Modh, 2018; Thompson, 2013). As the studies summarized below show, BFRBs often compromise quality of life and are associated with depression and other comorbid disorders.
Most research to date has focused on trichotillomania and skin picking disorder, the only BFRBs that have received specific codes in the DSM-5.
Before introducing each of the contributions to this special issue, we would like to take the reader on a brief journey through the different editions of the DSM and how they address what we refer to today as BFRBs.
In the DSM-I, trichotillomania is simply noted in the appendix and, together with “kleptomania” and other conditions, is considered an “obsessive compulsive reaction.” The diagnostic category in this edition that is perhaps closest to the current understanding of BFRBs is “Habit disturbance,” defined as “repetitive, simple activities.” (p. 41).
The DSM-II contains hardly any reference to conditions we now consider BFRBs except for “psychophysiological skin disorder” (p. 46), which has an unclear reference to skin picking. Neither trichotillomania nor “habit disturbance” are incorporated in DSM-II.
In the DSM-III, symptoms we now regard as BFRBs are occasionally mentioned but only as expressions of other disorders. For example, the diagnosis of “overanxious disorder” may manifest as “nervous habits such as nail biting or hair pulling” (p. 56), and plucking of hair is described as a possible sign of psychomotor agitation in major depressive disorder (p. 210).
In the DSM-III-R, trichotillomania is recognized as an “impulse control disorder not elsewhere classified” that can be accompanied by symptoms such as “head-banging, nail-biting, scratching, gnawing, excoriation, and other acts of self-mutilation” (p. 327). Interestingly, this condition—along with other BFRBs—is also mentioned as symptom of “stereotypy/habit disorder.” While this category contains many BFRBs, it also includes symptoms we would now categorize as stereotypic movement behavior and possibly nonsuicidal self-injury (NSSI). As in the DSM-III, symptoms such as nail biting and hair pulling are seen as possible manifestations of “overanxious disorder” and major depressive disorder (p. 219).
The DSM-IV classifies trichotillomania as an “impulse-control disorder not elsewhere classified,” as in the DSM-III-R, and lists other BFRBs as accompanying symptoms (p. 619). It highlights that a core difference between trichotillomania and obsessive-compulsive disorder is that in the latter condition the repetitive behaviors are performed in response to an obsession (p. 620). For the first time, skin picking is mentioned as a possible consequence of “body dysmorphic disorder” (p. 466). The DSM-IV makes a special effort not to pathologize any form of bodily nervousness, such as playing with one’s hair, and states that “among children, the diagnosis should be reserved for situations in which the behavior has persisted for several months” (p. 620). The diagnosis of “stereotypic movement disorder” within the category of stereotypy/habit disorder mentions some symptoms we now consider BFRBs, particularly skin picking. As in earlier editions, BFRBs are included as possible symptoms of other diseases, such as skin picking in “Tourette’s disorder” and “body dysmorphic disorder.”
The DSM-IV-TR makes one noteworthy change; it understands skin picking as an “impulse-control disorder not otherwise specified” and thus does not include it as an example of “stereotypic movement disorder.”
The DSM-5 introduces the term body-focused repetitive behavior (disorders) for the first time and subsumes them under “obsessive-compulsive and related disorders;” “trichotillomania (hair-pulling disorder)” and “excoriation (skin-picking) disorder” are each given their own code. Specific “body-focused repetitive behavior disorders” are mentioned only cursorily (e.g., lip chewing) or not at all, and the DSM-5 recommends they be diagnosed as body-focused repetitive behavior disorders under “other specified obsessive-compulsive and related disorder.”
This special issue brings together recent research on BFRBs. Reflecting the special recognition of trichotillomania and skin picking in prior editions of the DSM, many of the articles relate to these two conditions, but some deal with the entire spectrum of BFRBs.
Two of the contributions are primarily concerned with the psychometric properties of instruments for measuring trichotillomania. Kłosowska et al. confirm the reliability and validity of the Polish version of the Massachusetts General Hospital Hair Pulling Scale (MGH-HS), a widely used self-report measure of trichotillomania severity. Barber et al. also find that this scale has acceptable internal consistency but, in their sample, the test-retest reliability was low. They also report that scores on the MGH-HS and the National Institute of Mental Health Trichotillomania Severity Scale do not correlate well with a measure of hair loss. The authors highlight the need for the development of psychometrically sound instruments to assess severity of trichotillomania and other BFRBs.
The study by Capel, Petersen, Woods, Marcks, and Twohig corroborates a 2006 survey indicating that provider knowledge about trichotillomania and skin picking remains poor almost two decades later later. Of concern, many clinicians were not aware of evidence-based treatments for BFRBs. In view of clinicians’ knowledge gap and the reluctance of many individuals with BFRBs to seek help, self-help programs have been gaining momentum, and this topic is addressed by several studies in this issue. First, Mehrmann et al., using a web-based program, demonstrate the efficacy of self-help but highlight that low completion rates and motivation to change remain a challenge and are important to address in future research. In a similar vein, Haaga et al. underline the importance of adherence to self-help interventions and propose a number of strategies to reduce dropout. Dar et al. evaluate therapist-assisted programs designed to treat hair pulling (TrichStop) and skin picking (SkinPick). Once again, the improvement over time and, relatedly, the correlation of benefits with the number of completed sessions highlight the need to raise the completion rate of such programs. Another study shows that the effects of several self-help treatments, especially decoupling, are maintained at two-year follow-up (Moritz et al.). Another trial by the same group (Schmotz et al.) shows that less is more in self-help; a broad, unguided, web-based self-help approach is somewhat less effective, especially for nail biting, to a more focused approach that teaches single techniques (importantly, the techniques conveyed in the focused approach were included in the more comprehensive treatment). A study by Wiese et al. demonstrates that habit reversal training, the gold standard treatment for BFRB, is feasible both in person and via telehealth; the latter approach seems especially helpful in older individuals with less severe symptoms.
The study by Capel, Petersen, Levin, and Twohig looked at moderators of improvement for a fully automated website delivering acceptance-enhanced habit reversal training for trichotillomania. Younger age and greater psychological flexibility emerged as predictors for improved outcomes.
Several studies examined the phenomenology and clinical characteristics of BFRBs. Pendo et al. surveyed parents/caregivers on clinical characteristics of hair pulling and skin picking in preschool-aged children and healthy controls. Research on this age group is extremely limited. The results show that lying awake in bed and being bored, upset, and alone were common factors fostering the behavior. Greater sleep disturbance was noted in children with hair pulling but not skin picking relative to controls.
Skin picking and other BFRBs are heterogeneous in terms of phenomenology and causes. In line with this, De Nadai et al. identify five subgroups of individuals with skin picking based on their emotional response patterns. Greater consideration of this heterogeneity may improve outcomes via increased personalization of treatment. The study by Grant et al. is also related to skin picking. Compared to healthy controls, participants with BFRBs displayed higher levels of impulsivity, lower stress tolerance, and less usage of adaptive emotion regulation strategies.
Biscarri Clarke et al. show that individuals with BFRBs display higher scores for sensory-related experiences and sensory irritations (e.g., being more alert to background noises, being easily distractible, finding perceptual stimuli more intense) than healthy controls, with few differences across BFRBs.
Woods et al. present two studies on the clinical characteristics of trichotillomania. On average, participants reported two to three pulling sites. In line with past research, the scalp, eyebrows, eyelashes, and pubic area were the most common targets for pulling. Somewhat at odds with the current definition of NSSI (see above) and BFRBs, a majority of individuals reported using tools to perform the behavior. Pulling from the eyebrows and pubic area was associated with lower levels of automatic pulling compared to those who did not pull from these sites.
We hope that the research described in this special issue will attract other researchers to this relatively new field.
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