Suicides and Suicide Attempts During Long-Term Treatment with Antidepressants: A Meta-Analysis of 29 Placebo-Controlled Studies Including 6,934 Patients with Major Depressive Disorder

Background: It is unclear whether antidepressants can prevent suicides or suicide attempts, particularly during long-term use.

Methods: We carried out a comprehensive review of long-term studies of antidepressants (relapse prevention). Sources were obtained from 5 review articles and by searches of MEDLINE, PubMed Central and a hand search of bibliographies. We meta-analyzed placebo-controlled antidepressant RCTs of at least 3 months' duration and calculated suicide and suicide attempt incidence rates, incidence rate ratios and Peto odds ratios (ORs).

Results: Out of 807 studies screened 29 were included, covering 6,934 patients (5,529 patient-years). In total, 1.45 suicides and 2.76 suicide attempts per 1,000 patient-years were reported. Seven out of 8 suicides and 13 out of 14 suicide attempts occurred in antidepressant arms, resulting in incidence rate ratios of 5.03 (0.78-114.1; p = 0.102) for suicides and of 9.02 (1.58-193.6; p = 0.007) for suicide attempts. Peto ORs were 2.6 (0.6-11.2; nonsignificant) and 3.4 (1.1-11.0; p = 0.04), respectively. Dropouts due to unknown reasons were similar in the antidepressant and placebo arms (9.6 vs. 9.9%). The majority of suicides and suicide attempts originated from 1 study, accounting for a fifth of all patient-years in this meta-analysis. Leaving out this study resulted in a nonsignificant incidence rate ratio for suicide attempts of 3.83 (0.53-91.01).

Conclusions: Therapists should be aware of the lack of proof from RCTs that antidepressants prevent suicides and suicide attempts. We cannot conclude with certainty whether antidepressants increase the risk for suicide or suicide attempts. Researchers must report all suicides and suicide attempts in RCTs.