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  • Print publication year: 2010
  • Online publication date: August 2010

11 - Should there be a category: “grooming disorders?”



Grooming disorders, such as trichotillomania (TTM), nail biting, and skin picking, are receiving increasing attention from researchers and clinicians. This is in part due to their possible link to obsessive–compulsive disorder (OCD). It is imperative that these disorders are categorized correctly in order to facilitate research and aid diagnosis and treatment. However, within current psychiatric classification systems TTM is currently conceptualized as an impulse control disorder and nail biting, lip biting, and skin picking are not yet included in the official nomenclature. It is therefore unclear whether these grooming disorders should form a category on their own (i.e., “grooming disorders” or “pathological grooming behaviors”), or whether they should be classified as obsessive–compulsive spectrum disorders (OCSD), impulse control disorders, or as body-focused repetitive behaviors. This chapter will discuss these diagnostic and taxonomic issues particularly as they pertain to clinical practice, fostering further discussion on the psychopathology of aberrant grooming behaviors.


The positioning of TTM and other conditions characterized by self-directed repetitive behaviors (e.g., nail biting and pathological skin picking [PSP]) within existing psychiatric classification systems has recently been debated (e.g., Stein et al. 2007). Trichotillomania is classified in the most recent edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR; APA, 2000) as an impulse control disorder. However, some researchers suggest that TTM is an OCSD (Swedo and Leonard 1992).

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,American Psychiatric Association (1980): Diagnostic and Statistical Manual of Mental Disorders, 3rd edn. Washington, DC: APA.
,American Psychiatric Association (1987): Diagnostic and Statistical Manual of Mental Disorders, Text Revised, 3rd edn. Washington, DC: APA.
,American Psychiatric Association (1994): Diagnostic and Statistical Manual of Mental Disorders, 4th edn. Washington, DC: APA.
,American Psychiatric Association (2000): Diagnostic and Statistical Manual of Mental Disorders, Text Revised, 4th edn. Washington, DC: APA.
Arnold, LM, McElroy, SL, Mutasim, DFet al. (1998): Characteristics of 34 adults with psychogenic excoriation. J Clin Psychiatry 59:509–14.
Arnold, LM, Mutasim, DF and Dwight, MM (1999): An open clinical trial of fluvoxamine treatment of psychogenic excoriation. J Clin Psychopharm 19:15–18.
Arnold, LM, Auchenbach, MB and McElroy, SL (2001): Psychogenic excoriation: clinical features, proposed diagnostic criteria, epidemiology and approaches to treatment. CNS Drugs 15:351–9.
Baer, L (1993): Behavior therapy for obsessive–compulsive disorder in the office-based practice. J Clin Psychiatry 54(6 Suppl-10).
Benarroche, CL (1990): Trichotillomania symptoms and fluoxetine response. New Research Program and Abstracts, 143rd meeting of the APA, NY (NR327), 173.
Bergh, C, Eklund, T, Sodersten, P and Nordin, C (1997): Altered dopamine functioning in pathological gambling. Psychol Med 27:473–5.
Bienvenu, OJ, Samuels, JF, Riddle, MAet al. (2000): The relationship of obsessive– compulsive disorder to possible spectrum disorders: results from a family study. Biol Psychiatry 48:287–93.
Black, DW and Blum, N (1992): Trichotillomania treated with clomipramine and a topical steroid. Am J Psychiatry 149:842–3.
Bloch, MR, Elliott, M, Thompson, H and Koran, LM (2001): Fluoxetine in pathologic skin-picking: open-label and double-blind results. Psychosomatics 42:314–19.
Bloch, MH, Landeros-Weisenberger, A, Dombrowski, Pet al. (2007): Systematic review: pharmacological and behavioural treatment for trichotillomania. Biol Psychiatry 62:839–46.
Blum, K, Braverman, ER, Holder, JMet al. (2000): Reward deficiency syndrome: a biogenetic model for the diagnosis and treatment of impulsive, addictive, and compulsive behaviors. J Psychoact Drugs 32 Suppl:i–112.
Bogetto, F, Venturello, S, Albert, U, Maina, G and Ravizza, L (1999): Gender-related clinical differences in obsessive–compulsive disorder. Eur Psychiatry 14:434–41.
Bohne, A, Wilhelm, S, Keuthen, NJ, Baer, L and Jenike, MA (2002): Skin picking in German students: prevalence, phenomenology and associated characteristics. Behav Modif 26:320–39.
Bohne, A, Keuthen, NJ, Tuschen-Caffier, B and Wilhelm, S (2005): Cognitive inhibition in trichotillomania and obsessive–compulsive disorder. Behav Res Ther 43:923–42.
Bosnjak, A, Vucicevic-Boras, V and Miletic, I (2002): Incidence of oral habits in children with mixed dentition. J Oral Rehab 29:902–5.
Calikusu, C, Yucel, B, Polat, A and Baykal, C (2002): The relationship between psychogenic excoriation and psychiatric disorders: a comparative study. Turk Psikiyatri Derg 13:282–9.
Carter, WG and Shillcutt, SD (2006): Aripiprazole augmentation of venlaflaxine in the treatment of psychogenic excoriation. J Clin Psychiatry 67:1311.
Castle, DJ, Deale, A and Marks, IM (1995): Gender differences in obsessive compulsive disorder. Aust N Z J Psychiatry 29:114–17.
Chamberlain, S and Sahakian, BJ (2007): The neuropsychiatry of impulsivity. Curr Opin Psychiatry 20:255–61.
Chamberlain, SR, Fineberg, NA, Blackwell, AD, Robbins, TW and Sahakian, BJ (2006): Motor inhibition and cognitive flexibility in obsessive–compulsive disorder and trichotillomania. Am J Psychiatry 163:1282–4.
Chamberlain, S, Ipser, J, Stein, D and Fineberg, N (2008): Regarding “Systematic review: pharmacological and behavioral treatment for trichotillomania.”Biol Psychiatry 63:e33.
Christenson, GA, Mackenzie, TB and Mitchell, JE (1991a): Characteristics of 60 chronic hair pullers. Am J Psychiatry 148:365–70.
Christenson, GA, Mackenzie, TB, Mitchell, JE and Callies, AL (1991b): A placebo-controlled, double-blind crossover study of fluoxetine in trichotillomania. Am J Psychiatry 148:1566–71.
Christenson, GA, Pyle, RL and Mitchell, JE (1991c): Estimated lifetime prevalence of trichotillomania in college students. J Clin Psychiatry 52:415–17.
Christenson, GA, Mackenzie, TB and Mitchell, JE (1994): Adult men and women with trichotillomania. A comparison of male and female characteristics. Psychosomatics 35:142–9.
Christenson, RC (2004): Olanzapine augmentation of fluoxetine in the treatment of pathological skin picking. Can J Psychiatry 49:788–9.
Cohen, JD and Insel, TR (2008): Cognitive neuroscience and schizophrenia: translational research in need of a translator. Biol Psychiatry 64:2–3.
Oliveira, SKF (2007): PANDAS: A new disease?J Pediatr (Rio J) 83:201–8.
Deckersbach, T, Wilhelm, S, Keuthen, NJ, Baer, L and Jenike, MA (2002): Cognitive-behavior therapy for self-injurious skin picking: a case series. Behav Modif 26:361–77.
Denys, D, Megen, HJ and Westenberg, HG (2003): Emerging skin-picking after serotonin reuptake inhibitor-treatment in patients with obsessive–compulsive disorder: possible mechanisms and implications for clinical care. J Psychopharmacol 17:127–9.
Diefenbach, GJ, Tolin, DF, Hannan, S, Crocetto, J and Worhunsky, P (2005): Trichotillomania: impact on psychosocial functioning and quality of life. Behav Res Ther 43:869–84.
Dougherty, DD, Loh, R, Jenike, MA and Keuthen, NJ (2006): Single modality versus dual modality treatment for trichotillomania: sertraline, behavioral therapy, or both?J Clin Psychiatry 67:1086–92.
Du Toit, PL, Kradenburg, J, Niehaus, DJH and Stein, DJ (2001): Characteristics and phenomenology of hair-pulling: an exploration of subtypes. Compr Psychiatry 42:247–56.
Ellis, MPJ (1986): Oral habits: a behavioural approach. Br J Psychiatry 148:751–2.
Epperson, CN, McDougle, CJ and Price, LH (1996): Intranasal oxytocin in trichotillomania. Biol Psychiatry 40:559–61.
Epperson, CN, Fasula, D, Wasylink, S, Price, LH and McDougle, CJ (1999): Risperidone addition in serotonin reuptake inhibitor-resistant trichotillomania: three cases. J Child Adolesc Psychopharmacol 9:43–9.
Fineberg, NA, Saxena, S, Zohar, J and Craig, KJ (2007): Obsessive–compulsive disorder: boundary issues. CNS Spectr 12:359–64; 367–75.
Flessner, CA and Woods, DW (2006): Phenomenological characteristics, social problems and the economic impact associated with chronic skin picking. Behav Modif 30(6):944–63.
Flessner, CA, Mouton-Odum, S, Stocker, AJ and Keuthen, NJ (2007): internet-based treatment for self-injurious skin picking. Dermatol Online J 13:3.
Flessner, CA, Busch, AM, Heideman, PW and Woods, DW (2008a): Acceptance-enhanced behaviour therapy (AEBT) for trichotillomania and chronic skin picking: exploring the effects of component sequencing. Behav Modif 32:579–94.
Flessner, CA, Woods, DW, Franklin, ME, Cashin, SE and Keuthen, NJ, ,Trichotillomania Learning Center – Scientific Advisory Board (TLC-SAB) (2008b): The Milwaukee Inventory for Subtypes of Trichotillomania – Adult Version (MIST-A): development of an instrument for the assessment of “focused” and “automatic” hair pulling. J Psychopathol Behav Assess 30:20–30.
Friman, P, Finney, J and Christerpherson, E (1987): Behavioral treatment of trichotillomania: an evaluative overview. Behav Ther 15:249–64
Gadde, KM, Wagner, RH (2nd), Connor, KM and Foust, MS (2007): Escitalopram treatment of trichotillomania. Int Clin Psychopharmacol 22:39–42.
Garner, JP and Mason, GJ (2002): Evidence for a relationship between cage stereotypies and behavioural disinhibition in laboratory rodents. Behav Brain Res 136:83–92.
Garner, JP, Meehan, CL and Mench, JA (2003): Stereotypies in caged parrots, schizophrenia and autism: evidence for a common mechanism. Behav Brain Res 145:125–34.
Geller, JL, Erlen, J and Pinkus, RL (1986): A historical appraisal of America's experience with “pyromania” – a diagnosis in search of a disorder. Int J Law Psychiatry 9:201–29.
Grant, JE and Christenson, GA (2007): Examination of gender in pathologic grooming behaviors. Psychiatr Q 78:259–67.
Grant, JE, Odlaug, BL and Won, Kim , S (2007): Lamotrigine treatment of pathologic skin-picking: an open-label study. J Clin Psychiatry 68:1384–91.
Greer, JM and Capecchi, MR (2002): Hoxb8 is required for normal grooming behavior in mice. Neuron 33:23–34.
Hajcak, G, Franklin, ME, Simons, RF and Keuthen, NJ (2006): Hair pulling and skin picking in relation to affective distress and obsessive compulsive symptoms. J Psychopathol Behav Assess 28:179–87.
Himle, JA, Bordnick, PS and Thyer, BA (1995): A comparison of trichotillomania and obsessive–compulsive disorder. J Psychopathol Behav Assess 17:251–60.
Hollander, E (1993): Introduction. In: The Obsessive–Compulsive Related Disorders. Washington, DC: American Psychiatric Press.
Hollander, E, Stein, DJ, DeCaria, CMet al. (1992): Disorders related to OCD-neurobiology. Clin Neuropharmacol 15 Suppl 1 Pt A:259A–60A.
Iancu, I, Weizman, A, Kindler, S, Sasson, Y and Zohar, J. Serotonergic drugs in trichotillomania. J Nerv Ment Dis 184:641–4.
Jenike, MA (1992): Pharmacologic treatment of obsessive compulsive disorders. Psychiatr Clin North Am 15:895–919.
Kalivas, J, Kalivas, L, Gilman, D and Hayden, CT (1996): Sertraline in the treatment of neurotic excoriations and related disorders. Arch Dermatol 132:589–90.
Keuthen, NJ, Savage, CR, O'Sullivan, RLet al. (1996): Neuropsychological functioning in trichotillomania. Biol Psychiatry 39:747–9.
Keuthen, NJ, Jameson, M, Loh, Ret al. (2007a): Open-label escitalopram treatment for pathological skin picking. Int Clin Psychopharmacol 22:268–74.
Keuthen, NJ, Makris, N, Schlerf, JEet al. (2007b): Evidence for reduced cerebellar volumes in trichotillomania. Biol Psychiatry 61:374–81.
Koran, LM, Ringold, A and Hewlett, W (1992): Fluoxetine for trichotillomania: an open clinical trial. Psychopharmacol Bull 28:145–9.
Leonard, HL, Swedo, SE, Rapoport, JLet al. (1989): Treatment of obsessive–compulsive disorder with clomipramine and desipramine in children and adolescents. A double-blind crossover comparison. Arch Gen Psychiatry 46:1088–92.
Leonard, HL, Lenane, MC, Swedo, SE, Rettew, DC and Rapoport, JL (1991): A double-blind comparison of clomipramine and desipramine treatment of severe onychophagia (nail biting). Arch Gen Psychiatry 48:821–7.
Lewis, NDC and Yarnell, H (1951): Pathological Firesetting (Pyromania). Nervous and Mental Disease Monograph 82. New York: Coolidge Foundation.
Lochner, C and Stein, DJ (2006): Does work on obsessive–compulsive spectrum disorders contribute to understanding the heterogeneity of obsessive–compulsive disorder. Prog Neuropsychopharmacol Biol Psychiatry 30:353–61.
Lochner, C, du Toit, PL, Zungu-Dirwayi, Net al. (2001): Childhood trauma in obsessive–compulsive disorder, trichotillomania and controls. Depress Anxiety 14:1–3.
Lochner, C, Simeon, D, Niehaus, DJH and Stein, DJ (2002): Trichotillomania and skin picking: a phenomenological comparison. Depress Anxiety 15:83–6.
Lochner, C, Seedat, S, du Toit, PLet al. (2005): Obsessive–compulsive disorder and trichotillomania: a phenomenological comparison. BMC Psychiatry 5:2.
Lochner, C, Seedat, S, Niehaus, DJ and Stein, DJ (2006): Topiramate in the treatment of trichotillomania: an open-label pilot study. Int Clin Psychopharmacol 21:255–9.
Lyon, LS (1983): A behavioral treatment of compulsive lip biting. J Behav Ther Exp Psychiatry 14:275–6.
Malone, AJ and Massler, M (1952): Index of nailbiting in children. J Abnorm Soc Psychol 47:193–202.
McElroy, SL, Hudson, JI, PopeJr, HG, Keck, PE and Aizley, HG (1992). The DSM-III-R impulse control disorders not elsewhere classified: clinical characteristics and relationship to other psychiatric disorders. Am J Psychiatry 149:318–27.
McElroy, SL, Phillips, KA and Keck, PE (1994): Obsessive compulsive spectrum disorders. J Clin Psychiatry 55 Suppl:33–51.
Ninan, PT, Knight, B, Kirk, Let al. (1998): A controlled trial of venlaflaxine in trichotillomania: interim phase I results. Psychopharmacol Bull 34:221–4.
Ninan, PT, Rothbaum, BO, Marsteller, FA, Knight, BT and Eccard, MB (2000): A placebo-controlled trial of cognitive-behavioral therapy and clomipramine in trichotillomania. J Clin Psychiatry 61:47–50.
Odlaug, BL and Grant, JE (2007a): Childhood-onset pathologic skin picking: clinical characteristics and psychiatric comorbidity. Compr Psychiatry 48:388–93.
Odlaug, BL and Grant, JE (2007b): N-Acetyl cysteine in the treatment of grooming disorders. J Clin Psychopharmacol 27:227–8.
Odlaug, BL and Grant, JE (2008a): Clinical characteristics and medical complications of pathologic skin picking. Gen Hosp Psychiatry 30:61–6.
Odlaug, BL and Grant, JE (2008b): Trichotillomania and pathologic skin picking: clinical comparison with an examination of comorbidity. Ann Clin Psychiatry 20:57–63.
O'Sullivan, RL, Keuthen, NJ, Jenike, MA and Gumley, G (1996): Trichotillomania and carpal tunnel syndrome. J Clin Psychiatry 57:174.
O'Sullivan, RL, Keuthen, NJ, Christenson, GAet al. (1997a): Trichotillomania: behavioral symptom or clinical syndrome?Am J Psychiatry 154:1442–9.
O'Sullivan, RL, Rauch, SL, Breiter, HCet al. (1997b): Reduced basal ganglia volumes in trichotillomania measured via morphometric magnetic resonance imaging. Biol Psychiatry 42:39–45.
Phillips, KA, First, MB and Pincus, HA (2003a): Advancing the DSM: Dilemmas in Psychiatric Diagnosis. Washington, DC: American Psychiatric Association.
Phillips, KA, Price, LH, Greenberg, BD and Rasmussen, SA (2003b): Should the DSM diagnostic groupings be changed? In: Phillips, KA, First, MB and Pincus, HA, eds., Advancing the DSM: Dilemmas in Psychiatric Diagnosis. Washington, DC: American Psychiatric Association, pp. 57–84.
Pigott, TA, Pato, MT, Bernstein, SEet al. (1990): Controlled comparisons of clomipramine and fluoxetine in the treatment of obsessive–compulsive disorder. Behavioral and biological results. Arch Gen Psychiatry 47:926–32.
Pollard, CA, Ibe, IO, Krojanker, DNet al. (1991): Clomipramine treatment of trichotillomania: a follow-up report on four cases. J Clin Psychiatry 52:128–30.
Pukadan, D, Anthony, J, Mohandas, Eet al. (2008): Use of escitalopram in psychogenic excoriation. Aust N Z J Psychiatry 42:435–6.
Rasmussen, SA and Tsuang, MT (1984): The epidemiology of obsessive compulsive disorder. J Clin Psychiatry 45:450–7.
Rauch, SL, Wright, CI, Savage, CRet al. (2007): Brain activation during implicit sequence learning in individuals with trichotillomania. Psychiatry Res: Neuroimaging 154:233–40.
Rettew, DC, Cheslow, DL, Rapoport, JL, Leonard, HL and Lenane, MC (1991): Neuropsychological test performance in trichotillomania: a further link with obsessive–compulsive disorder. J Anxiety Disord 5:225–35.
Rettew, DC, Swedo, SE, Leonard, HL, Lenane, MC and Rapoport, JL (1992): Obsessions and compulsions across time in 79 children and adolescents with obsessive– compulsive disorder. J Am Acad Child Adolesc Psychiatry 31:1050–6.
Rosenbaum, MS and Ayllon, T (1981): The behavioral treatment of neurodermatitis through habit-reversal. Behav Res Therapy 19:313–18.
Rothbaum, BO, Shaw, L, Morris, R and Ninan, PT (1993): Prevalence of trichotillomania in a college freshman population. J Clin Psychiatry 54:72–3.
Sasso, DA, Kalanithi, PS, Trueblood, KVet al. (2006): Beneficial effects of the glutamate- modulating agent riluzole on disordered eating and pathologic skin-picking behaviors. J Clin Psychopharmacol 26:685–7.
Seedat, S, Kesler, S, Niehaus, DJ and Stein, DJ (2000): Pathological gambling behaviour: emergence secondary to treatment of Parkinson's disease with dopaminergic agents. Depress Anxiety 11:185–6.
Seedat, S, Stein, DJ and Harvey, BH (2001): Inositol in the treatment of trichotillomania and compulsive skin picking. J Clin Psychiatry 62:60–1.
Simeon, D, Stein, DJ, Gross, Set al. (1997): A double-blind trial of fluoxetine in pathologic skin picking. J Clin Psychiatry 58:341–7.
Stanley, MA, Bowers, TC, Swann, AC and Taylor, DJ (1991): Treatment of trichotillomania with fluoxetine. J Clin Psychiatry 52:282.
Stanley, MA, Swann, AC, Bowers, TC, Davis, ML and Taylor, DJ (1992): A comparison of clinical features in trichotillomania and obsessive–compulsive disorder. Behav Res Ther 30:39–44.
Stanley, MA, Breckenridge, JK, Swann, AC, Freeman, EB and Reich, L (1997): Fluvoxamine treatment of trichotillomania. J Clin Psychopharmacol 17:278–83.
Stein, DJ (2008): Is disorder X in category or spectrum Y? General considerations and application to the relationship between obsessive–compulsive disorder and anxiety disorders. Depress Anxiety 25:330–5.
Stein, DJ, Simeon, D, Cohen, LJ and Hollander, E (1995): Trichotillomania and obsessive–compulsive disorder. J Clin Psychiatry 56 Suppl 4:28–34.
Stein, DJ, Heerden, B, Hugo, Cet al. (2002): Functional brain imaging and pharmacotherapy in trichotillomania: single photon emission computed tomography before and after treatment with the selective serotonin reuptake inhibitor citalopram. Prog Neuropsychopharmacol Biol Psychiatry 26:885–90.
Stein, DJ, Garner, JP, Keuthen, NJet al. (2007): Trichotillomania, stereotypic movement disorder, and related disorders. Curr Psychiatry Rep 9:301–2.
Stewart, RS and Nejtek, VA (2003): An open-label, flexible dose study of olanzapine in the treatment of trichotillomania. J Clin Psychiatry 64:49–52.
Streichenwein, SM and Thornby, JI (1995): A long-term, double-blind, placebo-controlled crossover trial of the efficacy of fluoxetine for trichotillomania. Am J Psychiatry 152:1192–6.
Swedo, S (1993): Trichotillomania. In: Hollander, E, ed., The Obsessive–Compulsive Related Disorders. Washington, DC: American Psychiatric Press.
Swedo, SE and Leonard, HL (1992): Trichotillomania: an obsessive–compulsive disorder? Psychiatr Clin North Am 15:777–90.
Swedo, SE, Leonard, HL, Rapoport, JLet al. (1989): A double-blind comparison of clomipramine and desipramine in the treatment of trichotillomania (hair pulling). N Engl J Med 321:497–501.
Swedo, SE, Rapoport, JL, Leonard, HLet al. (1991): Regional cerebral metabolism of women with trichotillomania. Arch Gen Psychiatry 48:828–33.
Teng, EJ, Woods, DW, Twohig, MP and Marcks, BA (2002): Body-focused repetitive behaviour problems: prevalence in a non-referred population and differences in perceived somatic activity. Behav Modif 26:340–60.
Teng, EJ, Woods, DW and Twohig, MP (2006): Habit reversal treatment for chronic skin picking: a pilot investigation. Behav Modif 30:411–22.
Tukel, R, Keser, V, Karali, N, Olgun, T and Calikusu, C (2001): Comparison of clinical characteristics in trichotillomania and obsessive–compulsive disorder. J Anxiety Disord 15:433–41.
Turley, PK and Henson, JL (1983): Self-injurious lip-biting: etiology and management. J Pedontics 7:209–20.
Twohig, MP and Woods, DW (2001): Habit reversal as a treatment for chronic skin picking in typically developing male siblings. J Appl Behav Anal 34:217–20.
Twohig, MP, Woods, DW, Marcks, BA and Teng, EJ (2003): Evaluating the efficacy of habit reversal: comparison with a placebo control. J Clin Psychiatry 64:40–8.
Twohig, MP, Hayes, SC and Masuda, A (2006): A preliminary investigation of acceptance and commitment therapy as a treatment for chronic skin picking. Behav Res Ther 44:1513–22.
Ameringen, M, Mancini, C, Oakman, JM and Farvolden, P (1999): The potential role of haloperidol in the treatment of trichotillomania. J Affect Disord 56:219–26.
Minnen, A, Hoogduin, KAL, Keijsers, GPJ, Hellenbrand, I and Hendriks, GJ (2003): Treatment of trichotillomania with behavioral therapy or fluoxetine. Arch Gen Psychiatry 60:517–22.
Weissman, MM, Bland, RC, Canino, GJet al. (1994): The cross national epidemiology of obsessive compulsive disorder. The Cross National Collaborative Group. J Clin Psychiatry 55 Suppl:5–10.
Welch, JM, Lu, J, Rodriguiz, RMet al. (2007): Cortico-striatal synaptic defects and OCD-like behaviours in sapap3-mutant mice. Nature 448:894–901.
Wilhelm, A, Keuthen, NJ, Deckersbach, Tet al. (1999): Self-injurious skin picking: clinical characteristics and comorbidity. J Clin Psychiatry 60:454–9.
Winchel, RM, Jones, JS, Stanley, B, Molcho, A and Stanley, M (1992): Clinical characteristics of trichotillomania and its response to fluoxetine. J Clin Psychiatry 53:304–8.
Woods, DW, Miltenberger, RG and Flach, AD (1996): Habits, tics and stuttering: prevalence and relation to anxiety and somatic awareness. Behav Modif 20:216–25.
Woods, DW, Flessner, CA, Franklin, MEet al. (2006a): The Trichotillomania Impact Project (TIP): exploring phenomenology, functional impairment and treatment utilization. J Clin Psychiatry 67:1877–88.
Woods, DW, Wetterneck, CT and Flessner, CA (2006b): A controlled evaluation of acceptance and commitment therapy plus habit reversal for trichotillomania. Behav Res Ther 44:639–56.
,World Health Organization (1992): International Statistical Classification of Diseases and Health Related Problems, 10th Revision, Vol. 1. Geneva, Switzerland: WHO.
Zohar, J and Insel, TR (1987): Obsessive–compulsive disorder: psychobiological approaches to diagnosis, treatment, and pathophysiology. Biol Psychiatry 22:667–87.