Impulsivity and phase of illness in bipolar disorder

Background: Impulsivity is prominent in bipolar disorder, but there is little quantitative information relating it to phase of illness. Methods: We measured impulsivity in patients with bipolar disorder who had not met episode criteria for at least 6 months, patients who were manic, and healthy control subjects. Impulsivity was measured using the Barratt Impulsiveness Scale (BIS) and performance on the computerized Immediate Memory-Remote Memory Task (IMT-DMT), based on the Continuous Performance Test, which has been shown to reflect risk of impulsivity in other populations. Results: BIS scores in euthymic and manic bipolar subjects were identical, and were significantly elevated compared to controls. Commission errors (impulsive responses) on the IMT-DMT were elevated in manic subjects but were identical to controls in euthymic subjects. Measures of impulsivity did not appear related to depressive symptoms. Limitations: The number of subjects was too small for detailed investigation of the role of comorbidities; subjects were receiving pharmacological treatments. Conclusions: Impulsivity has state- and trait-related aspects in bipolar disorder.