Characterizing impulsivity in mania.
OBJECTIVE
To determine whether specific aspects of impulsivity (response disinhibition, inability to delay gratification, inattention) differ between healthy and bipolar manic subjects, and whether these aspects of impulsivity were associated with each other and severity of affective symptoms.


METHODS
Performance of 70 bipolar I manic or mixed patients was compared to that of 34 healthy subjects on three tasks specifically designed to study response inhibition, ability to delay gratification, and attention; namely, a stop signal task, a delayed reward task, and a continuous performance task, respectively. Correlations among tasks and with symptom ratings were also performed.


RESULTS
Bipolar subjects demonstrated significant deficits on all three tasks as compared to healthy subjects. Performance on the three tasks was largely independent. Task performance was not significantly associated with the severity of affective symptom ratings. However, measures of response inhibition and attention were sensitive to medication effects. Differences in the delayed reward task were independent of medication effects or symptom ratings. During the delayed reward task, although bipolar patients made their choices more slowly than healthy subjects, they were significantly more likely to choose a smaller, but more quickly obtained reward. Moreover, performance on this task was not associated with performance on the other impulsivity measures. Manic patients showed more impulsive responding than mixed patients.


CONCLUSIONS
Bipolar I manic patients demonstrate deficits on tests of various aspects of impulsivity as compared to healthy subjects. Some of these differences between groups may be mediated by medication effects. Findings suggested that inability to delay gratification (i.e., delayed reward task) was not simply a result of the speed of decision making or inattention, but rather that it reflected differences between bipolar and healthy subjects in the valuation of reward relative to delay.
Strakowski
Stephen M
SM
Division of Bipolar Disorders Research, Universtiy of Cincinnati College of Medicine, Cincinnati, OH, USA. stephen.strakowski@uc.edu
Fleck
David E
DE
DelBello
Melissa P
MP
Adler
Caleb M
CM
Shear
Paula K
PK
McElroy
Susan L
SL
Keck
Paul E
PE
Moss
Quinton
Q
Cerullo
Michael A
MA
Kotwal
Renu
R
Arndt
Stephan
S
D000328:Adult; D000704:Analysis of Variance; D018692:Antimanic Agents / Q000494:pharmacology / Q000627:therapeutic use; D001288:Attention / Q000187:drug effects; D001714:Bipolar Disorder / Q000150:complications* / Q000188:drug therapy / Q000523:psychology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000188:drug therapy / Q000209:etiology* / Q000523:psychology*; D007266:Inhibition, Psychological; D016014:Linear Models; D008297:Male; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D011930:Reaction Time / Q000187:drug effects; D055815:Young Adult
D018692:Antimanic Agents