• bipolar disorder;
  • personality disorders;
  • antisocial personality disorder;
  • impulsive behaviour;
  • substance-related disorders;
  • recurrence;
  • suicide attempted

Swann AC, Lijffijt M, Lane SD, Steinberg JL, Moeller FG. Interactions between bipolar disorder and antisocial personality disorder in trait impulsivity and severity of illness.

Objective:  We investigated trait impulsivity in bipolar disorder and antisocial personality disorder (ASPD) with respect to severity and course of illness.

Method:  Subjects included 78 controls, 34 ASPD, 61 bipolar disorder without Axis II disorder, and 24 bipolar disorder with ASPD, by Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (SCID-I and -II). Data were analyzed using general linear model and probit analysis.

Results:  Barratt Impulsiveness Scale (BIS-11) scores were higher in ASPD (effect sizes 0.5–0.8) or bipolar disorder (effect size 1.45) than in controls. Subjects with both had more suicide attempts and previous episodes than bipolar disorder alone, and more substance-use disorders and suicide attempts than ASPD alone. BIS-11 scores were not related to severity of crimes.

Conclusion:  Impulsivity was higher in bipolar disorder with or without ASPD than in ASPD alone, and higher in ASPD than in controls. Adverse effects of bipolar disorder in ASPD, but not of ASPD in bipolar disorder, were accounted for by increased impulsivity.