Sociocultural and clinical characteristics of patients with comorbid depressions: a comparison of substance abuse and non-substance abuse diagnoses.

Patients with three varieties of major depression (MD) were compared with respect to sociocultural and clinical characteristics. The patients sought psychiatric evaluation in an intake setting during a 6-year interval. The groups that were compared included MD (sole axis I diagnosis; N = 3,913); MD with a comorbid non-substance abuse ([MD-nonSA] N = 594); and MD with a comorbid substance abuse ([MD-SA] N = 690). Prominent demographic differences were found in the three groups, with males, lower social class status, younger age, and African American ethnicity being more prominent in MD-SA. The four demographic variables, axis I status, axis II diagnosis, and axis III diagnosis constituted the independent variable in an analysis of variance (ANOVA) main-effects comparison of social function (during last year and currently in three areas) and type of depression symptoms (somatic and psychological). Of the demographic variables, age and social class proved to have significant effects on social function and psychological symptoms. Each of the three "syndromic" axes (Axis I, Axis II, and Axis III) had a significant impact on social function and psychological symptoms. Only Axis III produced differences in somatic symptoms. The social and cultural implications of these results are discussed.