Variability of response to lithium augmentation in refractory depression.

Eighty-four patients with major depression refractory to a controlled antidepressant trial had lithium added to their ongoing treatment. Objective symptom ratings showed highly significant improvement in the sample as a whole. At discharge or after 24 days, 31% of the patients showed a marked response, 25% a partial response. Thus, 56% of patients had a significant positive response, while 44% were nonresponders. This study indicates that response to lithium augmentation may be quite variable and a 3-week trial is necessary to assess full benefit.