Recent advances in obsessive-compulsive disorder

A growing body of evidence from clinical phenomenology, including associated disorders, brain imaging, and neuropharmacologic studies, links the classic psychiatric syndrome of obsessive-compulsive disorder (OCD) to basal ganglia dysfunction and to the serotonin system. At present, OCD is the psychiatric syndrome for which a specific neurologic dysfunction is most strongly suggested, and for which a particularly compelling animal model has been found. It is proposed that dysfunction of basal ganglia-thalamic frontal cortical loops produce "positive" symptoms of excessive grooming, checking, and doubt most common in OCD. Perhaps most intriguing are preliminary data from clinical trials that a spectrum of other abnormal behaviors resembling excessive grooming in both animals and humans may be related to OCD. An ethologic perspective is suggested.