THE EFFECT OF LITHIUM CARBONATE IN COMBINATION WITH TRICYCLIC ANTIDEPRESSANTS IN ENDOGENOUS DEPRESSION: A double‐blind, multicenter trial

Forty‐five endogenously depressed patients in nine different hospitals were given, randomly, tricyclic antidepressants plus placebo, or tricyclic antidepressants plus lithium carbonate, for a minimum of 4 weeks. At the hospital with the largest single material, the six patients in the lithium group showed significantly greater improvement after 1 and 4 weeks than the seven patients in the placebo group. At the other hospitals, a total of 14 patients received lithium and 18 placebo, with no significant difference in outcome. However, the heterogeneity of this part of the material might easily have obscured any real difference in treatment outcome. Treatment response in the total material did not correlate significantly with diagnosis (e.g., whether unipolar or bipolar affective illness), age or sex. No significant side effects were reported. It is concluded that lithium does not antagonize, but rather seems to enhance the therapeutic effect of tricyclic antidepressants. Therefore, when an endogenously depressed patient is considered suited for longterm prophylactic lithium medication, such medication ought to be started while the patient is still depressed and under treatment with anti‐depressant drugs.