Summary:We present a patient with a severe obsessive-compulsive disorder, which was characterized by obsessive slowness and visual dysfunction, who had an abnormal single photon emission computed tomography study withN-isopropyl-p-[123I]iodoamphetamine. The initial study demonstrated decreased tracer deposition in the right basal ganglia and adjacent anterior right temporal lobe. After major symptom reduction by psychopharmacological therapy, a follow-up study demonstrated a return to normalcy.