Increased impulsivity associated with severity of suicide attempt history in patients with bipolar disorder.
BACKGROUND
Impulsivity is a prominent and measurable characteristic of bipolar disorder that can contribute to risk for suicidal behavior. The purpose of this study was to investigate the relationship between impulsivity and severity of past suicidal behavior, a potential predictor of eventual suicide, in patients with bipolar disorder.


METHODS
In bipolar disorder subjects with either a definite history of attempted suicide or no such history, impulsivity was assessed with both a questionnaire (Barratt Impulsiveness Scale) and behavioral laboratory performance measures (immediate memory/delayed memory tasks). Diagnosis was determined with the Structured Clinical Interview for DSM-IV. Interviews of patients and review of records were used to determine the number of past suicide attempts and the medical severity of the most severe attempt.


RESULTS
Subjects with a history of suicide attempts had more impulsive errors on the immediate memory task and had shorter response latencies, especially for impulsive responses. Impulsivity was highest in subjects with the most medically severe suicide attempts. Effects were not accounted for by presence of depression or mania at the time of testing. Barratt Impulsiveness Scale scores were numerically, but not significantly, higher in subjects with suicide attempts. A history of alcohol abuse was associated with greater probability of a suicide attempt. Multivariate analysis showed that ethanol abuse history and clinical state at the time of testing did not have a significant effect after impulsivity was taken into account.


CONCLUSIONS
These results suggest that a history of severe suicidal behavior in patients with bipolar disorder is associated with impulsivity, manifested as a tendency toward rapid, unplanned responses.
Swann
Alan C
AC
Department of Psychiatry, University of Texas Medical School at Houston, 1300 Moursund, Rm. 270, Houston, TX 77030, USA. Alan.C.Swann@uth.tmc.edu
Dougherty
Donald M
DM
Pazzaglia
Peggy J
PJ
Pham
Mary
M
Steinberg
Joel L
JL
Moeller
F Gerard
FG
D000328:Adult; D000437:Alcoholism / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D015897:Comorbidity; D039721:Diagnostic and Statistical Manual of Mental Disorders; D007174:Disruptive, Impulse Control, and Conduct Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D008297:Male; D008487:Medical History Taking; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010555:Personality Inventory / Q000706:statistics & numerical data; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time; D012307:Risk Factors; D012720:Severity of Illness Index; D013406:Suicide, Attempted / Q000523:psychology* / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires