Childhood movement disorders and obsessive compulsive disorder.

Recent investigations of childhood-onset obsessive compulsive disorder (OCD) and pediatric movement disorders such as tics, Tourette's syndrome (TS), and Sydenham's chorea suggest that these disorders may be related. Although comorbid obsessive-compulsive symptoms have long been recognized in individuals with TS, more recent studies have demonstrated that tics and TS are surprisingly common in children with primary OCD, and further, that the two disorders seem to have a common genetic vulnerability. Obsessive-compulsive symptoms are also manifest in Sydenham's chorea, a neurologic variant of rheumatic fever in which antistreptococcal antibodies are thought to cross-react with neuronal tissue, particularly within the basal ganglia, and cause inflammatory changes resulting in neuropsychiatric symptomatology. The frequent comorbidity of OCD and Sydenham's chorea and similar postulates of basal ganglia dysfunction for both disorders suggest that Sydenham's chorea may serve as a medical model for OCD. Of note, however, is that the medications (e.g., neuroleptics) that are effective in treating this and other movement disorders are distinctly different from those that are efficacious for OCD (e.g., serotonin reuptake blockers). Examinations of the similarities and differences among these various neuropsychiatric conditions may lead to greater understanding of the pathophysiology of OCD and offer further insights into the etiology and treatment of this troubling disorder.