Multicenter double-blind randomized parallel-group clinical trial of efficacy of the combination clomipramine (150 mg/day) plus lithium carbonate (750 mg/day) versus clomipramine (150 mg/day) plus placebo in the treatment of unipolar major depression.

Background: The therapeutic efficacy of adding lithium to an ongoing antidepressant in resistant depression is well known. However there is less data concerning the efficacy of giving lithium and antidepressant concurrently from the start of treatment.

Methodology: The primary objective of this study was to compare the efficacy of a combination of clomipramine+lithium (C+L) with that of clomipramine+placebo (C+P) in-patients with unipolar major depression, during the first 11 days of treatment. Secondary objectives were the assessment of effectiveness after 6 weeks and assessment of the safety of the combination clomipramine and lithium carbonate. C+L and C+P groups were compared for 6 weeks in a multicenter randomized trial of 141 patients hospitalized with a DSM-IV diagnosis of major depression. Efficacy was evaluated using the standard MADRS and CGI scales.

Results: Analysis of the 'as treatment ITT' population showed: the percentage reduction in MADRS scores between D0 and D11 in this population was better in the C+L group but not statistically significant (C+L: 32.1 vs. C+P: 27.4, P=0.07). Nevertheless, the comparison of mean MADRS scores showed a significant difference in the C+L group on days 4 (C+L: 25.1 vs. C+P: 27.8) and 7 (C+L: 18.6 vs. C+P: 21.5), P<0.05, and approaching significance on day 11 (C+L: 14.6 vs. C+P 17.2, P=0.054). On day 7, the number of patients in total remission was threefold higher in the C+L group than in the C+P group (15 vs. 4%, P<0.05) and twofold on day 11 (29 vs. 14%, P<0.05). CGI severity score showed C+L was superior to C+P on days 4, 7 and 11 and CGI improvement score was better in C+L group on day 11 (P<0.05). After 6 weeks of treatment no statistical difference was found between the two groups from the clinical point of view. Safety based upon clinical and laboratory parameters was satisfactory in both groups during the 6 weeks of the study.

Limitations: Patients with bipolar disorder, previously treated with clomipramine or with any other mood stabilizers during the previous week; or with suicide attempt during the current episode with a score > or =3 for item 10 of the MADRS were excluded from the study.

Conclusion: The results of this study suggests that lithium slightly to moderately potentiates antidepressant treatment in unipolar non-refractory patients with severe major depression in the first days of treatment but not as significantly as for the bipolar population.