Co-morbidity of select anxiety, affective, and psychotic disorders with cannabis dependence in Southwest California Indians.

Cannabis dependence is co-morbid with psychiatric disorders in general population surveys, but whether co-morbidity exists in American Indian populations is unknown. The aim of this study was to assess co-morbidity between cannabis dependence and psychiatric disorders in a community sample of Southwest California (SWC) Indians. Demographic information and DSMIII- R diagnoses, including differentiation of independent and cannabis-induced psychiatric disorders, were obtained using the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) developed for the Collaborative Study on the Genetics of Alcoholism (COGA) from 513 SWC Indian adults residing on contiguous reservations. Although SWC Indians in this sample had high rates of cannabis dependence (43% in men and 24% in women), cannabis-induced psychiatric disorders each occurred in 1% or less of the sample. No significant co-morbidity with independent psychiatric disorders was found. In SWC Indians, cannabis dependence may be less etiologically related to psychiatric disorders than in the general population.