PLATELET MONOAMINE-OXIDASE ACTIVITY IN PATIENTS WITH WINTER SEASONAL AFFECTIVE-DISORDER

The aim of the present study was to examine whether high or low levels of platelet monoamine oxidase (MAO) activity were associated with an increased risk of winter seasonal affective disorder (SAD) or of devel oping characteristic vegetative symptoms during episodes of the disord er. We also investigated the relationship between MAO activity and the Global Seasonality Scale (GSS), a measure of seasonal variation in sl eep length, social activity, mood, weight, appetite, and energy level. Patients with SAD (n = 49), patients with subsyndromal SAD (n = 11), and normal volunteers (n = 25) participated in the study. We found sig nificantly higher levels of platelet MAO activity in females but did n ot observe significant differences across age groups or between groups of patients tested in different seasons or mood states. MAO activity (whether high or low) was not associated with a significant increase i n risk of SAD or of developing hypersomnia, hyperphagia, or carbohydra te craving during episodes of winter depression. We found no significa nt relationship between GSS and MAO activity. Patients who had made su icide attempts during an episode of SAD had significantly lower mean l evels of platelet MAO activity than other patients.