Substance use disorders and overweight/obesity in bipolar I disorder: preliminary evidence for competing addictions.
OBJECTIVE
This investigation was undertaken to explore the relationship between alcohol/illicit drug dependence and overweight/obesity in individuals with bipolar I disorder.


METHODS
The data for this analysis were procured from the Canadian Community Health Survey-Mental Health and Well-Being (CCHS) conducted by Statistics Canada in 2002. Bipolar I disorder was defined as persons screening positive for a lifetime manic episode using the World Mental Health 2000 version of the Composite International Diagnostic Interview (WMH-CIDI). Substance abuse and illicit drug dependence were determined using criteria commensurate with the DSM-IV-TR. Overweight and obesity were defined as a body mass index of 25.0 to 29.9 and greater than or equal to 30.0 kg/m(2), respectively.


RESULTS
The total sample comprised 36,984 individuals (>or= 15 years old) screening positive for a lifetime manic episode. Subgroup analysis indicated that overweight/obese bipolar individuals had a significantly lower rate of substance dependence than the normal weight sample (13% vs. 21%, p < .01). Conversely, bipolar individuals who screened positive for substance dependence had a lower rate of overweight/obesity when compared with non-substance-dependent bipolar respondents (39% vs. 54%, p< .01). The inverse association between the presence of these 2 co-morbid conditions in bipolar I disorder continued to be statistically significant in multivariate analysis (OR = 0.57, 95% CI = 0.34 to 0.95, p < .05).


CONCLUSIONS
An inverse relationship between the presence of comorbid overweight/obesity and substance use disorders was observed in bipolar I disorder. These results suggest that comorbid addictive disorders (i.e., substance use and compulsive overeating) may compete for the same brain reward systems.
McIntyre
Roger S
RS
Department of Psychiatry, University of Toronto, Ontario, Canada. roger.mcintyre@uhn.on.ca
McElroy
Susan L
SL
Konarski
Jakub Z
JZ
Soczynska
Joanna K
JK
Bottas
Alexandra
A
Castel
Saulo
S
Wilkins
Kathryn
K
Kennedy
Sidney H
SH
D000293:Adolescent; D000328:Adult; D016739:Behavior, Addictive / Q000453:epidemiology* / Q000523:psychology*; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D015897:Comorbidity; D003710:Demography; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology* / Q000523:psychology; D050177:Overweight; D015995:Prevalence; D012720:Severity of Illness Index; D019966:Substance-Related Disorders / Q000453:epidemiology*; D011795:Surveys and Questionnaires