Inability to predict postdexamethasone cortisol levels by serum sodium levels.

Each of 42 hospitalized patients with unipolar major depression received a dexamethasone suppression test (DST) and had blood drawn for serum sodium and potassium tests within 3 days of admission. Unlike the patients in an earlier report by Tollefson et al., these patients showed no correlations between the DST results and the serum sodium levels. Although the DST identified depressive subtypes accurately, the serum sodium levels did not predict the DST results in this study.