The present article reviews direct and indirect evidence of the effects of
sex steroids on different aspects of sleep. It begins with a review of what
is known about the effects of steroid hormones on sleep and on central ner
vous system processes related to sleep, such as the GABA-ergic system, in a
nimals. It continues with a review of the effects of exogenous hormones on
human sleep and a review of studies comparing sleep during hypogonadal stat
es secondary to surgical or natural menopause. The article proceeds to revi
ew the data on the effects of the menstrual cycle on both subjective and ob
jective aspects of sleep and circadian temperature and melatonin rhythms in
samples of healthy women, women with premenstrual dysphoric disorder, and
women with primary insomnia. Then, the article reviews gender differences i
n sleep during depression and raises the possibility that sex steroids mode
rate these differences. Finally, the article concludes with a discussion of
the implications of the data reviewed for basic clinical, and methodologic
al aspects of sleep research.