EFFECTS OF THE MENSTRUAL-CYCLE ON DEPENDENT-VARIABLES IN MOOD DISORDER RESEARCH

The purpose of this article is to review the literature on the effects of the menstrual cycle on dependent variables in mood disorder resear ch to inform investigators which physiological measures are likely to be significantly affected by menstrual cycle fluctuations and precisel y how they might be affected. The following variables are discussed: p rolactin; growth hormone; the hypothalamic-pituitary-thyroid axis (inc luding thyrotropin, triiodothyronine, and thyroxine); the hypothalamic -pituitary-adrenal axis (cortisol; corticotropin, and beta-endorphin); melatonin; sleep; body temperature; and neurotransmitter activity (se rotonergic and adrenergic systems). Body temperature and plasma and ur inary norepinephrine vary predictably over the menstrual cycle. Prolac tin and beta-endorphin may have peaks in the periovulatory phase, wher eas serotonin levels in platelet-poor plasma may reach a nadir at that time. Triiodothyronine, thyroxine, cortisol, and melatonin do not app ear to vary systematically over the course of the menstrual cycle, whe reas the data for growth hormone, thyrotropin, corticotropin, and slee p are inconclusive.