Body-focused repetitive behaviors are difficult to define. trichotillomania (hair-pulling) was only included in the Diagnostic and Statistical Manual (DSM) in 1987, while excoriation "skin-picking" disorder was only added in the fifth edition in 2013. Hair-pulling moved from the umbrella category "impulse control disorder" to that of "obsessive-compulsive and related disorders" in the same edition. These behaviors are hard to categorize because they are not well researched and understood, they manifest hand in hand with a variety of other diagnoses, and they have both impulsive and compulsive features.
In animals, similar behaviors such as feather plucking and excessive licking are called "over-grooming behaviors," and are linked to stressful circumstances including being isolated, bored, cramped in a small space and frustrated. In humans, these same circumstances tend to be triggers, and "over-grooming behaviors" is one simple way to define BFRBs.
In the DSM 5, hair-pulling and skin-picking are defined in separate diagnoses as, roughly: recurrent pulling out or picking of one's hair and skin, with repeated effort to decrease or stop the behaviors, resulting in significant distress, when the symptoms are not caused by a medical condition or another mental disorder.
Researchers are advocating for the inclusion of a new umbrella category into the next version of the DSM. The category would be body-focused repetitive behaviors and would include hair-pulling, skin picking, as well as clinical levels of nail-biting and nose-picking (Stein et al., 2010).
In an article reviewing the literature on the subject, Roberts, O'Connor & Belanger (2013) define BFRBs as “a group of problematic, destructive, and apparently non-functional behaviors directed toward the body, including hair-pulling (trichotillomania, TTM) skin-picking, and nail-biting...BFRBs are recurrent, undesired, and often designed to remove part of the body…individuals with BFRBs report diminished control over the behavior…and a range of physical and psychological sequelae."
From my perspective as a psychodynamic therapist, these definitions leave out a couple of important elements. Specifically, I have learned that BFRBS do in fact have a function, as coping mechanisms, to soothe particularly sensitive nervous systems and to regulate emotions.
Adding these components, my definition of BFRBs is as follows: BFRBs are repetitive, over-grooming behaviors involving damage to the dermis (hair, skin or nails) that emerge as coping mechanisms (hard comforts, action symptoms) in people with particularly sensitive nervous systems, under a variety of stressors, the main function of which is to regulate emotions, bringing a short-lived sense of relief or escape that is usually followed by shame and frustration and can negatively impact many areas of life.
American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: American Psychiatric Publishing.
Roberts, S., O’Connor, K & Belanger, C. (2013). Emotion regulation and other psychological models for body-focused repetitive behaviors. Clinical Psychology review, 33, (pp. 745-762).
Stein, D., Grant, Jon, Franklin, M., Keuthen, N., Lochner, C., Singer, H., & Woods, D. (2010). Trichotillomania (hair pulling disorder), skin picking disorder, and stereotypic movement disorder: toward DSM-V. Depression and Anxiety, 27, (pp. 611-626.)