Cardiovascular, catecholamine and psychological responses to TRH in four types of affective disorder patients

When 500 micrograms of TRH is given intravenously, an increase in TSH, blood pressure, plasma catecholamines and positive emotions follows. Four groups of patients with major, minor or bipolar depression or schizoaffective disorder increased their TSH levels by similar amounts after TRH. The neurohormone also significantly increased diastolic blood pressure by 5.5 +/- 1.6 mm Hg, and decreased heart rate by 7.6 +/- 1.3 beats/min. There was a weak trend for bipolar depressives to have less cardiovascular response to TRH than the other groups. Plasma norepinephrine (NE) was higher after TRH than after placebo. The NE response differed between patient groups (P = .0023) because of a smaller response by major depressives. TRH decreased anger, tension and depression, and increased friendliness. Positive emotional responses were significantly greater in the bipolar depressives than in other groups. Forty-one other studies have found a subnormal TSH response does not distinguish between subtypes of the affective disorders, but cardiovascular, catecholamine and mood responses may do so.