Plasma MHPG in depressive disorders and relationship to the dexamethasone suppression test.

Plasma levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) were measured in 51 depressed patients and 43 normal control subjects. There were significantly higher plasma MHPG levels in the combined patient group with current or past melancholia (N = 28) than in nonmelancholic (N = 12) or dysthymic (N = 11) patients, in unipolar melancholic (N = 16) versus bipolar melancholic (N = 4) patients, and in patients with a major depressive episode who failed to suppress cortisol after the dexamethasone suppression test (N = 24) versus patients with normal suppression (N = 16). Anxiety symptoms correlated significantly with plasma MHPG levels. These results substantiate previous evidence that dysregulation of the hypothalamic-pituitary-adrenal axis and sympathetic nervous system occur together in a subgroup of depressed patients.