Does a history of substance abuse and illness chronicity predict increased impulsivity in bipolar disorder?

Background: Impulsivity is a common feature shared by bipolar disorder (BD) and substance use disorder (SUD). SUD and recurrent mood episodes are considered to be risk factors for poor outcome in BD. However, the association between impulsivity, illness chronicity and SUD in BD remains unexplored.

Methods: 103 BD patients with and without a lifetime history of SUD (36.82±11.34 years, 40 males) were recruited. Participants completed the SCID interview and were administered measures of impulsivity including the Barratt Impulsivity Scale (BIS) and selected tests of the Cambridge Neuropsychological Test Automated Battery (CANTAB). Hierarchical regression analyses explored the relationship between illness chronicity, SUD, and impulsivity.

Results: Variance in the BIS, number of false alarms on the Rapid Visual Processing task and other impulsivity indicators of the Cambridge Gambling Task (CGT) was not explained by the chosen variables. Only an increased number of commission errors in the negative condition of the Affective Go/No Go task was significantly associated with illness chronicity. Furthermore there was a trend suggesting a relationship between a lifetime history of SUD and increased propensity to risk-taking during the CGT.

Limitations: Potential limitations include medication and patients׳ remission status from SUD.

Conclusions: Contrary to our expectations impulsivity was generally not predicted by indicators of illness chronicity or SUD. While impulsivity could still be a marker of BD that is present before the onset of the disorder, the link between the number of mood episodes and specific indicators of impulsivity may be related to mechanisms of neuroprogression.