Erythrocyte soluble catechol-O-methyl transferase activity in primary affective disorder. A clinical and genetic study.

Erythrocyte catechol-O-methyl transferase (COMT) activity was studied in 53 patients with primary affective disorders and 38 controls and in selected relatives. Patients with affective disorders tended to have higher activity levels than normals, after correcting for sex differences. The COMT activity was positively correlated between relatives and is heritable. Within families, elevation of COMT activity distingushed healthy relatives from probands and ill relatives. This suggests that COMT activity elevation and affective illness do not show independent assortment and implies that COMT activity identifies genetic vulnerability to affective order.