DHEA may increase serotonin which in turn may be an explanation for its mood altering and anti-depressant effects experienced by some. This may also explain why DHEA has been reported to increase REM sleep. DHEA is low in postpartum depression, anorexia nervosa, and schizophrenia. DHEA appears to increase insulin sensitivity and lower lipids, which may be related to its reported relation to lower cardiac mortality in men. First of all, although there have been thousands of studies done on DHEA, most have been done on animals.
Human studies are much fewer and somewhat conflicting.
Of most concern are breast, cervical, uterine, ovarian and prostate malignancies, and BHP, all believed to be estrogen sensitive and the latter two testosterone related. There have been expressed concerns of liver damage or liver cancer with very high doses. Although animal studies have turned up no certain ill effects, there are no long-term studies in humans. Studies in cancer patients have turned up high levels of DHEA in breast and endometrial cancer. Retrospective studies have found elevated DHEA levels in postmenopausal women not taking estrogen and who had no evidence of breast cancer, were related to significantly higher incidences of breast cancer in the next 10 years.