Impulsiveness linked to severe clinical features in bipolar disorder

Jan 25 2013

By Lucy Piper, Senior medwireNews Reporter

Researchers have confirmed that trait-impulsiveness is associated with bipolar disorder and provide additional evidence of it being linked to a more severe clinical expression of the disease.

They found that Barratt Impulsiveness Scale (BIS)-10 scores were significantly higher, indicating increased impulsivity, in bipolar disorder patients who had a history of substance misuse or rapid cycling and mixed episodes.

There was no evidence, however, of an association between trait-impulsiveness and any variable relating to suicide attempts.

Bruno Etain, from Hôpital Albert Chenevier in Créteil, France and colleagues believe the findings indicate the possibility of using trait-impulsiveness as a means of identifying bipolar disorder patients at risk for substance misuse and mood instability and better tailoring their treatment.

"The codification of therapeutic interventions as a function of impulsiveness level is required," they say. "Nevertheless, such a dimension should be included in personalized medicine that is developing for bipolar patients."

A total of 385 euthymic bipolar disorder patients and 185 mentally healthy individuals participated in the study and comparison of their BIS-10 scores showed that the two groups had significantly different total scores, at approximately 66 for bipolar disorder patients versus 59 points for controls.

The bipolar disorder patients also scored significantly higher than controls for the three subscales: motor impulsiveness, attentional impulsiveness, and nonplanning impulsiveness.

The researchers note in the Journal of Affective Disorders that bipolar disorder patients who misused alcohol had significantly higher BIS-10 total scores than bipolar disorder patients who did not, with average scores of 69 versus 65. Respective scores for patients who misused cannabis and those who did not were 72 versus 65. Moreover, a history of both alcohol and cannabis misuse had an additive effect.

The findings were similar for patients with rapid cycling or mixed episodes, with patients with a history of at least one mixed episode or rapid cycling scoring an average of 69 on the BIS-10 versus a score of 65 for patients with neither history.

"These results may have several important clinical and research implications," say Etain et al. These include the use of trait impulsiveness to identify patients at greater risk for substance misuse, "making it possible to focus preventing measures on those most at risk."

Also, "patients with high impulsiveness scores may be more prone to mood instability... but they may also be more prone to severe, comorbid clinical expression," the team notes.

"Specific drug-based and psychological interventions targeting dyscontrol and hyperreactivity might therefore be possible."

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