Increased melatonin and delayed offset in menopausal depression: role of years past menopause, follicle-stimulating hormone, sleep end time, and body mass index.

CONTEXT: The constellation of endocrine patterns accompanying menopausal depression remains incompletely characterized.
OBJECTIVE: Our objective was to test the hypothesis that the amplitude or phase (timing) of melatonin circadian rhythms differs in menopausal depressed patients (DP) vs. normal controls women (NC).
DESIGN: We measured plasma melatonin every 30 min from 1800-1000 h in dim light (<30 lux) or dark, serum gonadotropins and steroids (1800 and 0600 h), and mood (Hamilton and Beck depression ratings).
SETTING: The study was conducted at a university hospital. PARTICIPANTS AND
SETTING: Twenty-nine (18 NC, 11 DP) peri- or postmenopausal women participated. MAIN OUTCOME MEASURES: We measured plasma melatonin (onset, offset, synthesis offset, duration, peak concentration, and area under the curve) and mood.
RESULTS: Multi- and univariate analyses of covariance showed that melatonin offset time was delayed (P = 0.045) and plasma melatonin was elevated in DP compared with NC (P = 0.044) across time intervals. Multiple regression analyses showed that years past menopause predicted melatonin duration and that melatonin duration, body mass index, years past menopause, FSH level, and sleep end time were significant predictors of baseline Hamilton (P = 0.0003) and Beck (P = 0.00004) depression scores.
CONCLUSIONS: Increased melatonin secretion that is phase delayed into the morning characterized menopausal DP vs. NC. Years past menopause, FSH, sleep end time, and body mass index may modulate effects of altered melatonin secretion in menopausal depression.