Context: Rates of clinical diagnoses of schizophrenia in African American individuals appear to be elevated compared with other ethnic groups in the United States, contradicting population rates derived from epidemiologic surveys.
Objective: To determine whether African American individuals would continue to exhibit significantly higher rates of clinical diagnoses of schizophrenia, even after controlling for age, sex, income, site, and education, as well as the presence or absence of serious affective disorder, as determined by experts blinded to race and ethnicity. A secondary objective was to determine if a similar pattern occurred in Latino subjects.
Design: Ethnicity-blinded and -unblinded diagnostic assessments were obtained in 241 African American individuals (mean [SD] age, 34.3 [8.1] years; 57% women), 220 non-Latino white individuals (mean [SD] age, 32.7 [8.5] years; 53% women), and 149 Latino individuals (mean [SD] age, 33.5 [8.0] years; 58% women) at 6 US sites. Logistic regression models were used to determine whether elevated rates of schizophrenia in African American individuals would persist after controlling for various confounding variables including blinded expert consensus diagnoses of serious affective illness.
Settings: Six academic medical centers across the United States.
Participants: Six hundred ten psychiatric inpatients and outpatients.
Main outcome measure: Relative odds of unblinded clinical diagnoses of schizophrenia in African American compared with white individuals.
Results: A significant ethnicity/race effect (χ(2)(2)=10.4, P=.01) was obtained when schizophrenia was narrowly defined, controlling for all other predictors. The odds ratio comparing African American with non-Latino white individuals was significant (odds ratio=2.7; 95% CI, 1.5-5.1). Similar differences between African American and white individuals occurred when schizophrenia was more broadly defined (odds ratio=2.5; 95% CI, 1.4-4.5). African American individuals did not differ significantly from white individuals in overall severity of manic and depressive symptoms but did evidence more severe psychosis.
Conclusions: African American individuals exhibited significantly higher rates of clinical diagnoses of schizophrenia than non-Latino white subjects, even after controlling for covariates such as serious affective disorder.