Background: Native Americans, overall, have the highest prevalence of alcohol dependence of any US ethnic group. In several large national surveys, alcohol dependence has been significantly associated with higher rates of anxiety and affective disorders (comorbidity). However, the frequencies of these disorders and their comorbidity with alcohol dependence in Native American populations are relatively unknown.
Methods: Demographic information and DSM-III-R diagnoses were obtained by using the Semi-Structured Assessment for the Genetics of Alcoholism developed for the Collaborative Study on the Genetics of Alcoholism from 483 Southwest California Indian adults residing on contiguous reservations. The Semi-Structured Assessment for the Genetics of Alcoholism allowed differentiation of each anxiety and affective disorder into one of three types: independent of substance use, concurrent with alcohol use, and concurrent with drug use.
Results: Sixty-six percent of the men and 53% of the women sampled had a lifetime diagnosis of alcohol dependence. Fourteen percent of the sample had a lifetime independent anxiety disorder, and 14% of the sample had a lifetime independent affective disorder. Alcohol- and/or drug-concurrent major depression occurred in 8%, and other alcohol- and/or drug-concurrent anxiety and affective disorders each occurred in less than 1.1% of the sample. No significant comorbidity was found between alcohol dependence and independent agoraphobia, social phobia, or major depressive disorder.
Conclusions: In this Southwest California Indian sample, rates of anxiety and affective disorders were substantially similar to those reported in the National Comorbidity Survey; however, comorbidity of independent disorders with alcohol dependence was not as pervasive as in the National Comorbidity Survey. Rates of concurrent anxiety and affective disorders were low. These data support the hypothesis that despite high rates of alcohol dependence, Southwest California Indians do not have higher rates of anxiety and affective disorders or comorbidity of these disorders with alcohol dependence than those reported in large surveys of non–American Indian populations.