Dexamethasone suppression test and urinary MHPG X SO4 determination in depressive disorders

The Dexamethasone Suppression Test (DST) was performed in 64 depressed inpatients, in 48 schizophrenics, and in 20 normal controls. Thirty-four percent of depressive inpatients were found to escape from dexamethasone suppression significantly higher than either schizophrenics (13%) or normal subjects (5%). Among subgroups, bipolar and unipolar endogenous depression patients had much higher abnormal rates for the DST (59% and 48%, respectively) than nonendogenous cases (8%). DST results were also found to be positively correlated with patients' Hamilton scores. These findings suggested that DST could be helpful in diagnosis, discrimination of subtypes, and in assessment of severity of symptoms. In 32 of the 64 depressed inpatients, urinary MHPG X SO4 excretion was determined and compared with 21 normal controls. Bipolar patients (n = 7) had less MHPG X SO4 excretion than unipolar endogenous patients (n = 16). Excretion was positively correlated with cortisol level at 17 hr after dexamethasone administration in 32 depressive inpatients, especially in the unipolar subgroup. A trend toward negative correlation, though not statistically significant, was found in bipolar depression between cortisol levels at 17 hr after dexamethasone administration and urinary MHPG X SO4 excretion. This may indicate that some differences in norepinephrine (NE) metabolism may exist between unipolar and bipolar depression, leading to differing correlations between deviation of central NE function and hypothalamus-pituitary-adrenal (HPA) axis in different subgroups of depression.