Body-Focused Repetitive Behaviors (BFRBs): The Complete Guide
Clinical · 3 min read · Published 2026-07-16 · Updated 2026-09-15
By Igor Gazivoda · Founder, Stop Biting
Habit reversal pooled a large effect (d = 0.80) over 18 studies and 575 participants, across six behaviour classes rather than nail biting alone. What BFRBs share.
What is a BFRB?
Body-focused repetitive behaviours (BFRBs) are a group of habits involving repeated actions directed at one's own body that cause physical damage and are difficult to stop despite repeated attempts. The category includes nail biting (onychophagia), skin picking (excoriation disorder), hair pulling (trichotillomania), cheek or lip biting, and a handful of related behaviours like nose picking (rhinotillexomania) at clinical severity.
What unites them isn't the specific body part or action but the underlying pattern: automatic, repetitive, self-directed behaviour that provides some form of sensory or emotional regulation, causes real physical consequences, and resists simple willpower-based stopping — the same core mechanics that make nail biting specifically so persistent.
The BFRB family
The major recognised BFRBs, and how they typically present:
- Nail biting (onychophagia) — biting nails, cuticles, or surrounding skin; the most common BFRB, affecting an estimated 20–30% of adults.
- Skin picking (excoriation disorder) — repetitive picking at skin, often at perceived imperfections, causing lesions and scarring; frequently co-occurs with nail biting.
- Hair pulling (trichotillomania) — pulling hair from the scalp, eyebrows, or eyelashes, resulting in noticeable hair loss; among the more clinically studied BFRBs.
- Cheek and lip biting — chewing the inside of the cheek or lip, sometimes to the point of sores; often overlooked as a BFRB because it's less visible than nail biting.
- Nose picking (rhinotillexomania) — at low frequency this is near-universal and not clinically significant; at high frequency and with resulting tissue damage it's recognised as a BFRB.
What they share neurologically
Across BFRBs, the behaviour tends to be encoded as a habit loop stored largely in the basal ganglia rather than driven primarily by conscious deliberation — meaning the actions often occur with limited real-time awareness, are triggered by similar states (stress, boredom, deep focus, fatigue), and produce a brief sensory or emotional payoff (tension relief, stimulation, a sense of "finishing" something) that reinforces the loop over time.
Studies of BFRBs collectively also find elevated rates of co-occurrence with each other — someone who bites their nails is meaningfully more likely than the general population to also pick at their skin, for instance — and elevated (though not universal) rates of co-occurring anxiety and OCD-spectrum symptoms, consistent with their DSM-5 grouping near obsessive-compulsive and related disorders.
How treatment differs by BFRB type
Habit Reversal Training is the common evidence-based backbone across nearly all BFRBs — its three trial-defined components are awareness training, competing response training and social support, and they apply regardless of whether the target behaviour is nail biting, skin picking, or hair pulling. A meta-analysis pooling 18 habit reversal studies and 575 participants across tics, stuttering, nail biting, thumb sucking, temporomandibular disorder and mixed oral-digital habits found a large effect versus control conditions from pre-treatment to final post-treatment assessment (d = 0.80) — a pooled post-treatment figure across all six behaviour classes, not a nail-biting effect size and not a follow-up result. Where treatment diverges is in the specifics of the competing response and the environmental modifications, which need to fit the particular behaviour: keeping nails filed short and hands occupied for nail biting; keeping skin moisturised and covering high-pick areas for skin picking; using specific hair-pulling-aware tools (like a "fidget" object positioned near where pulling typically happens) for trichotillomania.
For hair pulling and severe skin picking specifically, N-acetylcysteine (NAC) has more established research support than it does for nail biting, and some clinicians will suggest it as an adjunct for those particular BFRBs more readily than for nail biting alone. The adult trials are where that support sits: 56% of adults with trichotillomania were rated much or very much improved on NAC versus 16% on placebo, and 47% versus 19% among completers in a skin-picking trial. A Cochrane review graded the adult trichotillomania result as moderate-certainty evidence from a single trial — and found little to no difference in the one paediatric trial (25% versus 21.1%, low certainty).
Finding support
Because BFRBs as a category are less well known than more commonly discussed conditions like generalised anxiety, many people who bite their nails, pick their skin, or pull their hair have never been told these are a recognised, named, treatable group of behaviours — which can itself add unnecessary shame to something that's genuinely well understood clinically.
If you experience more than one BFRB, or if your primary BFRB is causing significant distress or physical damage, it's worth seeking a therapist with specific BFRB experience rather than general anxiety-focused therapy, since the treatment approach (HRT-based, behaviourally focused) differs somewhat from standard talk therapy for mood or anxiety alone.
Sources:
- Bate KS, Malouff JM, Thorsteinsson ET, Bhullar N. The efficacy of habit reversal therapy for tics, habit disorders, and stuttering: a meta-analytic review. Clin Psychol Rev. 2011;31(5):865–871.
- Twohig MP, Woods DW, Marcks BA, Teng EJ. Evaluating the efficacy of habit reversal: comparison with a placebo control. J Clin Psychiatry. 2003;64(1):40–48.
- Grant JE, Odlaug BL, Kim SW. N-acetylcysteine, a glutamate modulator, in the treatment of trichotillomania: a double-blind, placebo-controlled study. Arch Gen Psychiatry. 2009;66(7):756–763.
- Grant JE, Chamberlain SR, Redden SA, Leppink EW, Odlaug BL, Kim SW. N-Acetylcysteine in the Treatment of Excoriation Disorder: A Randomized Clinical Trial. JAMA Psychiatry. 2016;73(5):490–496.
- Hoffman J, Williams T, Rothbart R, Ipser JC, Fineberg N, Chamberlain SR, Stein DJ. Pharmacotherapy for trichotillomania. Cochrane Database Syst Rev. 2021;9(9):CD007662.
- Lee DK, Lipner SR. Update on Diagnosis and Management of Onychophagia and Onychotillomania. Int J Environ Res Public Health. 2022;19(6):3392.
Where to go next
If you are wondering whether nail biting counts as self-harm, see our page on the difference.
If you are wondering whether nail biting counts as self-harm, see is nail biting a form of self-harm.
A note on medical advice
This article is for general information only and is not medical advice. Nail biting and related body-focused repetitive behaviours (BFRBs) can have medical and psychological dimensions that deserve individual attention. For diagnosis or treatment — of BFRBs, infections, or any condition discussed here — consult a qualified professional: a GP or dermatologist for physical symptoms, or a therapist experienced with BFRBs for the habit itself. The TLC Foundation for Body-Focused Repetitive Behaviors (bfrb.org) maintains a directory of BFRB-informed clinicians.