Impulsivity and risk-taking in borderline personality disorder with and without substance use disorders

Impulsivity and risk taking propensity were assessed in participants with borderline personality disorder (BPD-only; n = 19), BPD and a current or past substance use disorder (BPD-SUD; n = 32), and a matched comparison group (MC; n = 28). Participants were administered behavioral measures of two facets of the multidimensional construct of impulsivity [GoStop, delay discounting task (DDT)], one measure of risk-taking propensity [Balloon Analog Risk Task (BART)], and two self-report measures of impulsivity (i.e., Barrett Impulsiveness Scale, Eysenck Impulsiveness Scale). The BPD-SUD group, but not the BPD-only group, discounted delayed rewards faster than the MC group on the DDT, suggesting that the BPD-SUD/MC group difference may be because of the SUD rather than BPD. In contrast, both the BPD-SUD and BPD-only groups exhibited poorer behavioral response inhibition compared with the MC group, but the two BPD groups did not differ from one another. This finding suggests that the differences in behavioral response inhibition may be because of BPD rather than SUD and that behavioral response disinhibition may be a core feature of BPD. None of the groups differed on the measure of risk-taking propensity (i.e., BART). On self-report questionnaires, the BPD-SUD group reported more impulsivity than the BPD-only group and both BPD groups reported more impulsivity than the MC group. Data from the DDT and self-report measures provide partial support for the hypothesis that BPD individuals with a SUD are more impulsive than BPD individuals without a SUD on some facets of impulsivity (e.g., desire to obtain a smaller immediate reward rather than wait to obtain a larger reward in the future). Results suggest that behavioral response inhibition may be a novel treatment outcome variable for BPD treatment studies.