Clinical symptoms and platelet monoamine oxidase in subgroups and different states of affective disorders.

Platelet monoamine oxidase activity (MAO) and clinical symptoms were examined in 116 individuals, 32 acute depressed patients and 84 healthy controls. The enzyme activity was lower in depressed women than controls. MAO activity correlated positively with rated clinical state in depressed women but not in depressed men. Patients were reexamined after 10 years and categorized into affective psychosis (endogenous) or neurotic depression (International Statistical Classification of Diseases, Injuries and Causes of Death, 1987; ICD-9). Neurotic depressed occurred frequently in the low activity group. Endogenously depressed showed positive correlation between MAO activity and rated clinical state. The association between platelet MAO activity and clinical state is discussed.