“It has been increasingly recognized that nonwhite patients are more likely than white patients to be clinically diagnosed with schizophrenia when presenting with psychotic symptoms. Proposed causes of this phenomenon include racial bias of clinicians, lack of cultural understanding between clinicians and nonwhite patients, and differing symptomatic presentations among races.”

The authors hypothesized that the clinical overdiagnosis of schizophrenia in nonwhites persists in the public sector and explored whether differences between races in secondary (comorbid) diagnoses contribute to discrepancies in primary diagnoses. They performed a retrospective chart review of 173 patients with psychotic disorders discharged during a recent 7-month period from a large state psychiatric hospital.

“Black patients were significantly more likely to be diagnosed with schizophrenia than white patients (odds ratio =5.1)… This racial pattern was observed even in the subgroup of patients hospitalized for the first time (odds ratio = 7.0). Neither the type nor frequency of comorbid diagnoses significantly differed between races. Additionally, black patients received higher doses of antipsychotic medication.”

“The schizophrenia subgroup had significantly more black patients than all other subgroups…. Indeed, 78.6% of black patients versus 42.7% of white patients were diagnosed with schizophrenia (chi-square=19.6, df=1, p<.0001). Much of this variance was due to the racial differences in the paranoid subtype (chi-square=9.2, df=1, p=.003). Conversely, black patients were significantly less likely to receive an affective disorder diagnosis (chi-square = 7.9, df=1, p=.005), with much of the variance due to different rates of diagnosis of bipolar disorder specifically (chi-square = 4.6, df=1, p=.03).”

“These findings are unlikely to reflect racial differences in socioeconomic strata. Thus, it appears that despite the advent of DSM-III and DSM-III-R and increased awareness of misdiagnosis in nonwhite patients, black patients in the public sector continue to be overdiagnosed with schizophrenia.…The reasons for overdiagnosis of schizophrenia in black patients remain elusive. Although racial bias has been proposed, the racial and ethnic diversity of the diagnosing clinicians in this study makes that less likely. Nonetheless, race bias may be inadvertently learned, despite the race of the trainee, in training programs that have predominantly white instructors and patients… Possible reasons for dissimilar dosing between races include the possibility that black patients are perceived as having greater potential for violence than white patients, leading to increased medication dosing…Despite its limitations, this study suggests that race continues to affect clinical diagnoses made in patients with psychosis which may lead to inaccurate assessment and, potentially, inadequate treatment. Continued attention to differences between white and nonwhite patients in clinical presentation, applicability of diagnostic criteria, and assignment of treatment is critical to help understand this problem.”