Comorbidity of bipolar disorder and substance abuse in Costa Rica: pedigree- and population-based studies.
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.


METHODS
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. Chi(2) 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 chi(2) = 16.84, P = 0.00004). In comorbid subjects, alcohol dependence tended to predate the first manic episode (chi(2) = 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.
Escamilla
Michael A
MA
Department of Psychiatry, (7792), University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA. escamillam@uthscsa,edu
Batki
Steven
S
Reus
Victor I
VI
Spesny
Mitzi
M
Molina
Julio
J
Service
Susan
S
Vinogradov
Sophia
S
Neylan
Tom
T
Mathews
Carol
C
Meza
Luis
L
Gallegos
Alvaro
A
Montero
A Patricia
AP
Cruz
Maria L
ML
Neuhaus
John
J
Roche
Erin
E
Smith
Lauren
L
Leon
Pedro
P
Freimer
Nelson B
NB
D001714:Bipolar Disorder / Q000150:complications / Q000208:ethnology / Q000235:genetics*; D015897:Comorbidity; D003364:Costa Rica / Q000453:epidemiology / Q000208:ethnology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D015995:Prevalence; D012307:Risk Factors; D012737:Sex Factors; D019966:Substance-Related Disorders / Q000150:complications / Q000208:ethnology / Q000235:genetics*