Short-term efficacy of tricyclic antidepressants revisited: a meta-analytic study

The original data from the placebo-arms and the tricyclic-arms of all parallel randomized controlled three-arm studies, which had been conducted in the period 1979-1991 fur a drug under development in order to obtain marketing authorization for the indication major depression, were included in a meta-analysis, Thirty-two placebo-controlled studies including 4314 patients were analyzed. The intention to treat analysis resulted in 46% responders (at least 50% improvement on the Hamilton Depression Rating Scale) in the tricyclic antidepressant group and 31% in the placebo-group (CI95%-difference 11.5-17.1%). The number needed to treat for responders was 7 (CI95% 5-8). In 10 out of 33 studies, a statistically significant difference in favor of tricyclic antidepressant compared to placebo was found for responders. The responder rate in the placebo-group varied fi-om 6 to 52%. We conclude that tricyclic antidepressants are efficacious in the short-term treatment of major depression. However, the magnitude of the effect is rather modest. Because 69% of the placebo-controlled studies with a tricyclic antidepressant did not show a statistically significant difference in favor of tricyclic antidepressant and the placebo rare varied considerably from study to study, equivalence studies with tricyclic antidepressant as comparator without a placebo-control are not sufficient fur demonstrating efficacy. Therefore in major depression, placebo-controlled studies are still necessary to demonstrate efficacy. (C) 2001 Elsevier Science B.V. All rights reserved.