Neurobiology of obsessive-compulsive disorder

Abstract

Abstract As defined in the Diagnonstic and Statistical Manual of Mental Disorders, 4th (DSM-IV), obsessivecompulsive disorder (OCD) is an anxiety disorder, characterized by obsessions—recurrent, unwanted, and distressing thoughts, images, or impulses—and/or compulsions—complex, repetitive, rule-governed behaviors that the patient feels driven to perform. Patients usually try to actively dismiss obsessions or neutralize them by seeking reassurance, avoiding situational triggers, or by engaging in compulsions. Although compulsions generally serve to alleviate anxiety, they can also engender anxiety if they become too arduous or time-consuming. The proposed lifetime prevalence of OCD is 2%–3% in adolescents and adults. Approximately half of all OCD patients first present in childhood, before age 15 (Karno et al., 1988). Peak symptom changes often occur around age 10 years (Leonard et al., 1992) and the symptom profile in children can be quite variable. A child with only OCD or tics may develop additional symptoms months or years later. Although there are many similarities between childhood and adult onset OCD, Geller et al. (1998a) propose that there are enough differences between childhoodand adult-onset OCD to view childhood-onset OCD as a developmental subtype of the disorder. The major difference between childhoodand adult-onset OCD is that in children compulsions often precede obsessions and they may lack insight about their symptoms. Childhood-onset OCD is also associated with a poorer treatment response, higher familial risk, and a high rate of comorbid tic, disruptive, and developmental disorders.