Depression, antidepressants, and plasma DBH.

Plasma levels of dopamine-beta-hydroxylase (DBH) were determined in 16 unmedicated patients with major depressive episodes (nonpsychotic) and in an equal number of normal subjects, before and after 4 weeks of treatment with tricyclic antidepressants. Some eight patients were treated with amitriptyline, and the remainder received desipramine. The controls remained medication free during the entire experimental period. Degrees of depression were quantified before and after treatment with the Hamilton Rating Scale of Depression (HRSD). There were no significant differences between the depressed patients and the controls on levels of DBH. Similarly, there were no within-group, pre-posttreatment differences on the enzyme levels in either group. Pre- and posttreatment HRSD scores did not correlate with corresponding plasma DBH levels. Plasma levels of amitriptyline, nortriptyline (product of amitriptyline in the body), and desipramine at the end of 4 weeks of treatment also failed to correlate with the enzyme levels.