Background: The purpose of this study was to determine the prevalence of substance use disorders (substance abuse or substance dependence: SA/SD) in a large sample of Bipolar Type I (BPI) patients drawn from the Costa Rican population and to describe the effects of SA/SD on the course of their bipolar disorder. Method: 110 subjects from two high-risk (for BPI) Costa Rican pedigrees and 205 unrelated Costa Rican BPI subjects were assessed using structured interviews and a best estimate process. χ2 and survival analyses were performed to assess the effect of gender on comorbidity risk, and the effect of comorbidity on the clinical course of BPI. Results: SA/SD (primarily alcohol dependence) occurred in 17% of the BPI patients from the population sample and 35% of the BPI patients from the pedigree sample. Comorbid SA/SD was strongly associated with gender χ2 = 16.84, P = 0.00004). In comorbid subjects, alcohol dependence tended to predate the first manic episode (χ2 = 6.54, P < 0.025). History of SA/SD did not significantly alter the prevalence of psychosis or age of onset of mania in BPI subjects. Conclusions: These results suggest that SA/SD comorbidity rates are lower in this type of population than in BPI patient populations in the US. Gender is a strong predictor of comorbidity prevalence in BPI patients from this population. Although SA/SD may be a risk factor for precipitating BPI in those at risk, in this population comorbid BPI subjects do not have a different onset or course of BPI in comparison to BPI patients without comorbidity.
Bibliographical noteFunding Information:
Supported by grants from the National Institute of Mental Health (MH00916, MH49499, MH48695, MH47563) the National Alliance for Research on Schizophrenia and Depression, and the American Psychiatric Association’s Program for Minority Research Training in Psychiatry.
- Bipolar disorder
- Substance abuse