Impulsivity is associated with suicide attempt in mood disorders with complex moderation by diagnosis and subjective social status.

Aims: Suicide Attempt (SA) is common among individuals with mood disorders, and trait impulsivity is a strongly associated risk factor. However, findings on the relationship between trait impulsivity and SA vary widely. We hypothesized that impulsivity is associated with SA in patients with mood disorders (either MDD or BD), and we tested how diagnostic category and Subjective Social Status (SSS) may impact this relationship. Methods: Participants with bipolar disorder (BD; types I and II) and major depressive disorder (MDD) were assessed at intake in a cross-sectional analysis. Impulsivity was measured with the Short UPPS-P Impulsive Behavior Scale (S-UPPS-P), which assesses five facets of impulsivity (negative urgency, positive urgency, premeditation, perseverance and sensation seeking). SA history was determined using the Columbia-Suicide Severity Rating Scale (C-SSRS). The sample included 153 participants (74 BD, 79 MDD), of whom 66 had at least one prior suicide attempt. Logistic regression analyses examined associations between impulsivity scores and prior SA, controlling for age and sex. We also tested how controlling for diagnosis and SSS affected the model, and whether diagnosis and SSS moderated the relationship between impulsivity and attempt. Results: S-UPPS-P total score and the subscales negative urgency and positive urgency were associated with prior suicide attempt across the sample. S-UPPS-P total score was no longer significant when adjusting for diagnosis and SSS. When testing how these three variables may interact, we found a significant three-way interaction between S-UPPS-P total score, diagnosis, and SSS. Conclusion: The relationship between impulsivity and suicide attempt is complex and moderated by diagnosis and SSS.