Suicide attempts in major depressive episode: evidence from the BRIDGE-II-Mix study

The Bipolar Disorders: Improving Diagnosis, Guidance, and Education (BRIDGE-II-Mix) study aimed to estimate the frequency of mixed states in patients with a major depressive episode (MDE) according to different definitions and to compare their clinical validity, looking into specific features such as suicidality.

A total of 2,811 subjects were enrolled in this multicenter cross-sectional study. Psychiatric symptoms, and sociodemographic and clinical variables were collected. The analysis compared the characteristics of patients with MDE with (MDE-SA group) and without (MDE-NSA) a history of suicide attempts.

The history of suicide attempts was registered in 628 patients (22.34%). In the MDE-SA group, women (72.5%, p = 0.028), (hypo)mania in first-degree relatives (20.5%, p < 0.0001), psychotic features (15.1%, p < 0.0001), and atypical features (9.2%, p = 0.009) were more prevalent. MDE-SA patients' previous responses to treatment with antidepressants included more (hypo)manic switches [odds ratio (OR) = 1.97, 95% confidence interval (CI): 1.58-2.44, p < 0.0001], treatment resistance (OR = 2.07, 95% CI: 1.72-2.49, p < 0.0001), mood lability (OR = 1.98, 95% CI: 1.65-2.39, p < 0.0001), and irritability (OR = 1.80, 95% CI: 1.48-2.17, p < 0.0001). Multivariate analysis evidenced that risky behavior, psychomotor agitation and impulsivity, and borderline personality and substance use disorders were the variables most frequently associated with previous suicide attempts. In the MDE-SA group, 75 patients (11.9%) fulfilled Diagnostic and Statistical Manual (DSM)-5 criteria for MDE with mixed features, and 250 patients (39.8%) fulfilled research-based diagnostic criteria for a mixed depressive episode.

Important differences between MDE-SA and MDE-NSA patients have emerged. Early identification of symptoms such as risky behavior, psychomotor agitation, and impulsivity in patients with MDE, and treatment of mixed depressive states could represent a major step in suicide prevention.