Antipsychotic therapy and suicide risk in patients with treatment-resistant depression: target trial emulation framework study

Abstract

Background

Previous studies investigating the effectiveness of augmentation therapy have been limited.

Aims

To evaluate the effectiveness of antipsychotic augmentation therapies among patients with treatment-resistant depression.

Method

We included patients diagnosed with depression receiving two antidepressant courses within 1 year between 2009 and 2020 and used the clone-censor-weight approach to address time-lag bias. Participants were assigned to either an antipsychotic or a third-line antidepressant. Primary outcomes were suicide attempt and suicide death. Cardiovascular death and all-cause mortality were considered as safety outcomes. Weighted pooled logistic regression and non-parametric bootstrapping were used to estimate approximate hazard ratios and 95% confidence intervals.

Results

The cohort included 39 949 patients receiving antipsychotics and the same number of matched antidepressant patients. The mean age was 51.2 (standard deviation 16.0) years, and 37.3% of participants were male. Compared with patients who received third-line antidepressants, those receiving antipsychotics had reduced risk of suicide attempt (sub-distribution hazard ratio 0.77; 95% CI 0.72–0.83) but not suicide death (adjusted hazard ratio 1.08; 95% CI 0.93–1.27). After applying the clone-censor-weight approach, there was no association between antipsychotic augmentation and reduced risk of suicide attempt (hazard ratio 1.06; 95% CI 0.89–1.29) or suicide death (hazard ratio 1.22; 95% CI 0.91–1.71). However, antipsychotic users had increased risk of all-cause mortality (hazard ratio 1.21; 95% CI 1.07–1.33).

Conclusions

Antipsychotic augmentation was not associated with reduced risk of suicide-related outcomes when time-lag bias was addressed; however, it was associated with increased all-cause mortality. These findings do not support the use of antipsychotic augmentation in patients with treatment-resistant depression.