Decreased suicide rates in recent antidepressant clinical trials

The last systematic analysis of suicidality in antidepressant clinical trials submitted for approval by the US Food and Drug Administration was in 2000. Given the attention to suicide and antidepressants in the early 2000s, the authors aimed to evaluate if there have been any changes in suicide rates in antidepressant clinical trials following 2000.

The Integrated Safety Summary data from approval packets for 14 investigational antidepressant programs (1991-2013, 40,857 patients, 10,890.5 exposure years) were used to calculate suicides and suicide attempts per 100,000 patient exposure years (standardized rates) for antidepressant and placebo treatment groups separately. Suicides/suicide attempt rates, mean age, and percent female were compared between 1991 and 1998 (pre-2000) and 2002-2013 (post-2000). Drug-placebo differences in suicide/suicide attempt rates were explored.

Among antidepressant-treated patients, the standardized suicide rate decreased significantly from pre- to post-2000 (643.6 to 25.8, p < 0.0001) as did the standardized suicide attempt rate (3975.7 to 645.4, p < 0.0001). For placebo-treated patients, the decrease was not significant for suicide rate (471.1 to 174.2, p = 0.66) but was significant for suicide attempt rate (from 3538.3 to 522.6, p < 0.001). Regression analysis showed a similar pattern with suicide/suicide attempt rates decreasing over time. None of the drug-placebo comparisons in suicide or suicide attempt rates were statistically significant. There was no change in percent female or mean age of patients in trials pre- and post-2000.

Deaths by suicide and suicide attempts have decreased significantly in antidepressant clinical trials following 2000 compared to the decade before 2000. Basic demographic features of the patients have remained consistent and medication treatment effects on suicidality were not apparent. These findings may reflect enhanced screening procedures and effective exclusion of suicidal patients in clinical trials for depression.