Platelet Monoamine Oxidase Activity and the Classification of Depression

An attempt was made to compare platelet monoamine oxidase (MAO) activity in descriptively based types of nonbipolar depression. Platelet MAO activity was significantly higher in depression secondary to chronic anxiety, compared with primary unipolar depression and depression secondary to borderline personality, and in women compared with men. No significant differences were observed between endogenous-nonendogenous, delusional-nondelusional, psychomotor states, or different age groups.