Correlation between plasma cortisol and CSF catecholamines in endogenous depressed dexamethasone nonsuppressors

Nineteen endogenous depressive in-patients (13 with major depression and 6 with bipolar disorder-depressed) and 10 other patients with dysthymic disorder serving as the control group were given the dexamethasone suppression test (DST, 1 mg/subject). The results showed that the DST sensitivity in endogenous depressives was 73.7% and the specificity was 90%. After the patients were treated daily for 6 weeks with 150-200 mg imipramine, 88.9% of those endogenous depressive patients who previously had a positive DST response exhibited a negative response. Moreover, a significantly negative correlation was found between the CSF norepinephrine level and the pre-dexamethasone 4 p.m. plasma cortisol level in those endogenous depressed patients who had a positive DST response. Pre-treatment data also showed that the 4 p.m. plasma cortisol had a significant negative correlation with CSF dopamine. These findings suggest that endogenous depression with positive DST could be related not only to a lower norepinephrine level, but also to a lower dopamine level.