Plasma cortisol, catecholamine and cyclic AMP levels, response to dexamethasone suppression test and platelet MAO activity in manic-depressive patients. A longitudinal study

Plasma cortisol, catecholamine and cyclic AMP levels, response to dexamethasone suppression test and platelet MAO activity have been determined in 15 patients suffering from bipolar affective psychosis, each examined during a depressive, a manic and an euthymic phase, and in 15 sex- and age-matched normal controls. Mean basal and post-dexamethasone cortisol levels have been found to be enhanced in patients during depression, but not during mania or free intervals. Non-suppression of cortisol secretion after dexamethasone has been observed in 46.7% of patients while in a state of depression, but in none of them during mania or euthymia. Mean plasma noradrenaline and adrenaline levels, which are thought to be the most reliable biochemical indices of emotional arousal, have been found to be increased in patients during mania, but not during depression. No significant difference has been observed between patients during any phase of their illness and controls with regard to mean plasma cyclic AMP levels and platelet MAO activity. These results confirm the state-dependent overactivity of HPA axis in endogenous depression, and suggest that it should not be regarded as a correlate of emotional hyperarousal. Moreover, they do not support the postulated role of plasma cyclic AMP as a state variable and of platelet MAO activity as a trait variable for manic-depressive illness.