title: Trait impulsivity is increased in bipolar disorder patients with comorbid alcohol use disorders.
abstract: BACKGROUND
  Up to 60% of bipolar disorder (BD) patients develop alcohol use disorders (AUD) at some point in their lives. The causes of this highly prevalent comorbidity are unknown. High trait impulsivity characterizes both isolated BD and AUD and may be a link to explain the association between BD and AUD. In this study, our aims were to investigate whether BD patients with comorbid AUD would present higher trait impulsivity levels compared to BD patients without comorbid AUD, and whether trait impulsivity levels differ within subgroups of BD according to the subcategory of AUD (abuse vs. dependence, alcoholism alone vs. alcoholism plus drug use disorders).
  
  
  METHODS
  Forty-seven outpatients with BD with comorbid AUD (alcoholic BD group) were compared to 66 outpatients with BD alone (nonalcoholic BD group) and to 90 healthy controls (HC). BD and AUD diagnoses were obtained using the Structured Clinical Interview for DSM-IV diagnoses. Impulsivity was assessed using the Barratt Impulsiveness Scale (BIS-11), a self-report instrument that measures trait impulsivity in three domains: nonplanning, attentional and motor.
  
  
  RESULTS
  Alcoholic BD patients scored significantly higher than nonalcoholic BD and HC on the total and on each subscale BIS scores. Within the alcoholic BD patients, alcohol abusers and alcohol dependents did not statistically differ from each other on the BIS-11 scores. BD patients with AUD plus drug use disorders presented statistically higher nonplanning impulsivity than BD patients with AUD alone.
  
  
  CONCLUSIONS
  This was a cross-sectional study and causal inferences about the relationship between impulsivity and the comorbidity phenomenon cannot be made. Increased impulsivity may be a trait marker for the co-occurrence between BD and AUD, and mediate some severe manifestations of this comorbidity.
authors.affiliation: Department of Psychiatry, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
authors.forename: Fabiano G
authors.initials: FG
authors.lastname: Nery
authors.forename: John P
authors.initials: JP
authors.lastname: Hatch
authors.forename: E Serap
authors.initials: ES
authors.lastname: Monkul
authors.forename: Koji
authors.initials: K
authors.lastname: Matsuo
authors.forename: Giovana B
authors.initials: GB
authors.lastname: Zunta-Soares
authors.forename: Charles L
authors.initials: CL
authors.lastname: Bowden
authors.forename: Jair C
authors.initials: JC
authors.lastname: Soares
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000453:epidemiology / Q000523:psychology*; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000453:epidemiology / Q000523:psychology*; D016022:Case-Control Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000523:psychology; D008297:Male; D008875:Middle Aged; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000523:psychology*