Plasma growth hormone (GH) release after TRH injection was investigated in 27 unipolar and 23 bipolar depressive women, and in 39 normal female controls matched for age, sex and menopausal status. Peaks of GH secretion after TRH were observed in some depressive patients as well as in some normal controls, but there were no significant differences in GH response after TRH administration between patients and controls. The implications of these findings are discussed in reference to such factors as non-specific stress responses and abnormal neuroendocrine circadian rhythms in affectively ill patients.