Self-reported inhibition predicts history of suicide attempts in bipolar disorder and major depression

Studies have reliably identified an association between suicide attempts and executive functions such as decision making (DM) and inhibitory control (IC) in patients with mood disorders. As such, the present study aimed to investigate the association between inhibition, DM, impulsivity and the history of suicide attempts in individuals with bipolar (BD) or major depressive disorder (MDD), identifying which assessment instruments may be most strongly associated with suicide in clinical samples.

The sample included 80 control subjects and two groups of patients with BD and MDD, matched by age and education (26 with a history of suicide attempts [MD+], and 26 with no such history [MD-]). Participants completed behavioral and self-report measures of DM and IC, which were compared between groups using ANCOVA, followed by logistic regression for patients with mood disorders only, and the presence or absence of a history of suicide as the outcome.

Cognitive performance did not differ between groups. The MD+ group showed significantly higher motor and attentional impulsivity on the BIS-11 than the MD- and control groups. A regression analysis containing these scores showed that motor impulsivity was the only significant predictor of a history of suicide (OR = 1.14; 95%CI 1.00-1.30).

Self-reported motor impulsivity was a significant predictor of suicide. These findings underscore the importance of self-report measures in neuropsychological assessment, and their contributions to the management and prognosis of patients with mood disorders. Lastly, they point to the role of impulsivity as a target for interventions and public policy on suicide prevention.