Specific aspects of impulsivity, including difficulty concentrating and restlessness, can predict the course of illness in patients with bipolar disorder, according to the findings of a study in the Australian & New Zealand Journal of Psychiatry.
The heterogeneous experiences of individuals with bipolar disorder make it difficult to identify reliable predictors of illness severity. Because patients with bipolar disorder face a risk for suicide that is 20 to 30 times that of the general population, uncovering such predictors is critical.
Adult outpatients (n=120) and controls (n=51) were recruited from university hospitals in Germany and Austria. Eligible individuals were diagnosed with bipolar disorder type I or II according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, and had no other serious axis I disorder. Euthymia was validated according to the Hamilton Rating Scale for Depression and the Young Mania Rating Scale.
Participants’ impulsivity was assessed on the Barratt Impulsiveness Scale, a 30-item self-report questionnaire with attentional, motor, and nonplanning subscales. The authors followed up with participants with bipolar disorder every 8 weeks for an average duration of 54.4 weeks. Rather than rating by the number of hospital admissions or episodes, illness severity was rated according to the morbidity index, which measures time spent with symptoms and severity of symptoms.
Overall, trait impulsiveness (ie, impulsivity as a stable characteristic) was significantly associated with worse outcomes. The attentional subscale of the Barratt Impulsiveness Scale, which includes items rating ability to concentrate, racing thoughts, fidgeting, and having “extraneous thoughts,” was particularly associated with increased illness severity. The motor and nonplanning subscales did not differ significantly between participants with bipolar disorder and controls.
The authors suggested that this self-report measure may be useful as a “risk assessment for morbidity.”
The study’s generalizability may be limited, the authors noted, as there were more female participants than male, and recruitment occurred only through university hospitals. Although the study’s duration was long, they added, observations from a single year will not necessarily capture the lifelong experience of bipolar disorder.
Rote J, Dingelstadt A, Aigner A, et al. Impulsivity predicts illness severity in long-term course of bipolar disorder: A prospective approach [published online July 4, 2018]. Aust N Z J Psychiatry. doi:10.1177/0004867418783062