Impulsivity in bipolar and substance use disorders

Bipolar disorder (BD) is commonly associated with increased impulsivity, particularly during manic and depressed episodes; also impulsivity remains elevated during euthymic phases. Impulsivity is also a factor in the initiation and maintenance of substance use disorders (SUD). Impulsivity can predispose to substance abuse or can result from it. Impulsivity appears to be relatively independent of mood state and is higher in individuals with past substance use. Thus, we wanted to compare the impulsivity of BD and SUD closely associated with impulsivity and identify potential differences.

Impulsivity was evaluated by the Barratt Impulsiveness Scale (BIS-11A), in 35 bipolar interepisode disorder male patients without comorbid substance use disorder and 40 substance use disorder male patients. The BIS-11A mean scores for the two groups were compared through one-way between-groups ANOVA.

There was no difference between the BD and substance use disorder groups on total and subscale attentional, motor impulsivity measures. However, for the male patients there was difference on the nonplanning subscale. The male BD patient group scored higher than the male substance use disorder patient group regarding nonplanning impulsivity.

Our results replicate the findings that interepisode BD and substance use disorder patients both have increased total impulsivity; furthermore, the findings also indicate that trait impulsivity is not completely the same in subscales. Both groups were similar on attention and motor impulsivity subscales; however, on the nonplanning subscale, BD patients were more impulsive than the substance use disorder patients.