This study utilized a large clinical dataset of patients representative of those in routine U.S. psychiatric practice to assess the influence of sociodemographic variables and diagnostic class on health plan membership (public or private). Data on patients with schizophrenia or other psychotic disorders (n=288) and patients with mood or anxiety disorders (n=1304) were obtained from a cross-sectional practice-based survey conducted by the American Psychiatric Institute for Research and Education. The likelihood of health plan membership was lower among males and among those from a minority race/ethnicity. Health plan membership was also affected by educational attainment and employment status. Even after controlling for these sociodemographic determinants of health plan membership, individuals with schizophrenia/other psychotic disorders were significantly less likely to belong to a health plan than those with mood/anxiety disorders.