The authors compared 10 nondepressed patients with obsessive-compulsive disorder with 10 normal control subjects of the same sex and similar age for cerebral glucose metabolic rates obtained using positron emission tomography. Obsessive-compulsive patients showed significantly elevated metabolic rates in the whole cerebral hemispheres, heads of the caudate nuclei, orbital gyri, and the orbital gyri relative to the ipsilateral hemisphere (the orbital-hemisphere ratio). These results are similar to those the authors reported previously for another group of obsessive-compulsive patients and normal control subjects.