Studies on biogenic amine metabolizing enzymes (DBH, COMT, MAO) and pathogenesis of affective illness. III. Platelet monoamine oxidase activity in endogenous depression.

Platelet MAO activity was determined in blood from 31 healthy persons and 43 persons with endogenous depressive syndrome. It was found that the enzyme activity is significantly higher in women than in men, both in healthy controls and in affective illness groups. Statistically significant lowering of the enzyme activity was found in the group of women with affective illness as compared with healthy women controls (P less than 0.05). Although the latter phenomenon is true of all three diagnostic subgroups of affective disorder (bipolar, unipolar, undifferentiated), it is most pronounced, and statistically significant only in the group of women with an undifferentiated course of disease. A small rise in the enzyme activity was noticed in some patients during remission, as compared with a period of depression, but this was not statistically significant. Analysis of the possible links between MAO activity and the clinical picture, or the severity of depression, revealed no significant correlations. No correlation was found between the level of MAO activity and a family history of psychiatric disturbances in general, and affective disorders in particular--in either women or in men.