Impulsivity and compulsivity in patients with trichotillomania or skin picking compared with patients with obsessive-compulsive disorder

To compare impulsivity and compulsivity, we performed a case control study comparing a group of 20 patients with obsessive-compulsive disorder with a group of 20 patients with skin picking and/or trichotillomania (SP/T). The instruments used were Structured Clinical Interview for DSM-IV Axis I Diagnosis, Yale-Brown Obsessive-Compulsive Scale, Schalling Impulsivity Scale, and Hamilton Anxiety and Depression Inventories. A Multidimensional Impulsive-Compulsive Spectrum Assessment Instrument was designed for this particular study. The Yale-Brown Obsessive-Compulsive Scale scores were significantly higher in patients with obsessive-compulsive disorder, compared with patients with SP/T (F = 90.29; P < .001). The Hamilton Inventories and Schalling Impulsivity Scale revealed no significant intergroup differences. The Multidimensional Impulsive-Compulsive Spectrum Assessment Instrument allowed us to find 6 statistically significant differences between groups: the ability or inability to delay an impulse, quick response or action planning, feelings of pleasure or guilt during or after an act, ritualization, and whether the patient believes he/she has losses or benefits if prevented from acting. In conclusion, SP/T should deserve further attention about their classification in future versions of diagnostic manuals because, as in International Classification of Diseases, Tenth Revision, the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition includes these disorders in the same chapter as pathological gambling, kleptomania, pyromania and others. Despite their resemblance to compulsions, their classification under the Obsessive-Compulsive Spectrum needs particular phenomenological and neurobiologic investigation.