High reverse T3 levels in manic an unipolar depressed women.

A relatively high percentage of patients with affective disorders have abnormalities of thyroid function, and over 60% of endogenously depressed and most manic patients show a blunted thyroid-stimulating hormone (TSH) response to thyroid-releasing hormone (TRH) injections. We now replicate earlier findings concerning relatively high 3,3',5'-triiodothyronine (reverse T3) levels in unipolar depressives and find similarly high levels in manic women. The significance of the present finding is unknown, but measurement of reverse T3 levels as a potential tool in differential diagnosis of affective disorders and in psychobiological research should be explored further.