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October 1978

Activities of Types A and B MAO and Catechol-O-methyltransferase in Blood Cells and Skin Fibroblasts of Normal and Chronic Schizophrenic Subjects

Author Affiliations

From the Mailman Research Center, McLean Division of Massachusetts General Hospital, Belmont, Mass, and the Departments of Psychiatry and Neurology-Neuropathology, Harvard Medical School, Boston. Dr Groshong was a Fellow of the National Association of Mental Health. Dr Baldessarini is a Career Investigator of the National Institute of Mental Health. Dr Groshong is now with the Department of Psychiatry, University of California at Los Angeles-NPI. Dr Gibson is now with the Department of Pathology, University of Colorado Medical Center, Denver.

Arch Gen Psychiatry. 1978;35(10):1198-1205. doi:10.1001/archpsyc.1978.01770340048004

• We assayed activities of monoamine oxidase (MAO) type B in blood platelets and type A (and B) in fibroblasts cultured from punch biopsy specimens of skin, as well as of catechol-Omethyltransferase (COMT) in erythrocytes and fibroblasts. Fibroblasts contained moderate amounts of both forms of MAO (types A and B) found in human brain and large amounts of COMT activity. Activities of both enzymes correlated poorly between fibroblasts and blood cells. Comparing carefully diagnosed chronic schizophrenics with age-matched normal young men, we found no difference in these biochemical variables, nor could we distinguish patients with paranoid symptoms. In contrast, we confirmed markedly lower MAO activities in platelet samples from chronic patients provided by colleagues at the National Institute of Mental Health. Results concerning MAO and COMT activities are now sufficiently inconsistently characteristic of schizophrenics as to question their clinical applicability and to indicate a need for further critical evaluation, with special attention to diagnosis, matching of subjects, and effects of possible spurious environmental variables.

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