The research project detailed in specific, herein, is a PET study of two major, related neuropsychiatric diseases, OCD and TD. These diseases share features in common not only with each other, but with other neuropsychiatric anxiety, mood, and movement disorders. Regional cerebral glucose metabolism will be studied with fluorodeoxyglucose (FDG), while dopamine and serotonin receptor binding will be measured with fluoro-ethyl-spiperone (FES). The specific aim is to determine the neuro-anatomical localization of biochemical abnormalities which underlie the expression of these illnesses. Six groups of subject will be studied with both FDG and FES: 1. OCD without compulsions ("pure obsessionals"), 2. OCD with compulsions, 3. TD without OCD symptoms, 4. TD with OCD symptoms, 5. TD relatives with chronic multiple tic (CMT) and 6. normals. It is hypothesized that subjects with purely mental symptoms (#1) will have orbital gyrus and caudate abnormalities on both FDG and FES-PET, while pure motor symptom patients (#5) will be abnormal only in the putamen. Subject group #3 will have caudate and putamen pathology, while #2 and #4 orbital, caudate and putamen abnormalities and will be indistinguishable from each other. The data collected will be inspected for other findings as well. These studies will further understanding not only of the pathophysiological similarities and differences between OCD and TD (and thus further efforts to control these illnesses), but will also shed light on the neuro-chemical-anatomical organization of higher cerebral function.