Treatment-resistant depression and suicidality

Background: Thirty percent of patients with treatment-resistant depression (TRD) attempt suicide at least once during their lifetime. However, it is unclear what the attempted and completed suicide incidences are in TRD patients after initiating a treatment, and whether specific treatments increase or decrease these incidences. Methods: We searched PubMed systematically for studies of depressed patients who failed at least two antidepressant therapies and were followed for at least three months after initiating a treatment. We estimated attempted and completed suicide incidences using a Poisson meta-analysis. Given the lack of controlled comparisons, we used a meta-regression to estimate whether these incidences differed between treatments. Results: We included 30 studies investigating suicidality in 32 TRD samples, undergoing deep brain stimulation (DBS, n = 9), vagal nerve stimulation (VNS, n = 9), electroconvulsive therapy (ECT, n = 5), treatment-as-usual (n = 3), capsulotomy (n = 2), cognitive behavioral therapy (n = 2), ketamine (n = 1), and epidural cortical stimulation (n = 1). The overall incidence of completed suicides was 0.47 per 100 patient years (95% CI: 0.22–1.00), and of attempted suicides 4.66 per 100 patient years (95% CI: 3.53–6.23). No differences were found in incidences following DBS, VNS or ECT. Limitations: Suicidality is poorly recorded in many studies limiting the number of studies available. Conclusions: The completed and attempted suicide incidences are high (0.47 and 4.66 per 100 patient years respectively), but these incidences did not differ between three end of the line treatments (DBS, VNS or ECT). Given the high suicide risk in TRD patients, clinical trials should consider suicidality as an explicit outcome measure.