Impact on suicidality of the borderline personality traits impulsivity and affective instability

The aim of this study was to test the impact on suicidality (suicide threats, attempts) of the borderline personality disorder (BPD) traits impulsivity and affective instability in mood disorders.

In a general psychiatry private practice (nontertiary care), consecutive remitted, non-substance-abusing outpatients--138 with bipolar II disorder (BP II) and 71 with major depressive disorder (MDD)--self-assessed using the Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II) Questionnaire.

The frequency (higher in BP II) of suicidality was 14%; impulsivity, 37%; and affective instability, 58%. The suicidality-positive patients (n = 30), when compared with the suicidality-negative patients (n = 179), had more BP II, more impulsivity (odds ratio [OR], 5.5; 95% confidence interval [CI], 2.3 to 13.3), and more affective instability (OR, 2.4; 95% CI, 0.99 to 6.0). Logistic regression of suicidality vs impulsivity and affective instability (controlled for BP II; age; and interactions among BP II, age, impulsivity, and affective instability), showed that impulsivity was a strong independent predictor of suicidality (OR, 4.3; 95% CI, 1.7 to 10.6), and that affective instability was not an independent predictor of suicidality (OR,1.6; 95% 0.6 to 4.1). BP II showed neither confounding nor interactions.

Results showed a strong independent impact of impulsivity-but not affective instability-on suicidality in BPD. No confounding by mood and substance disorders supported the BPD nature of these associations.