Using the cultural formulation to resolve uncertainty in diagnoses of psychosis among ethnoculturally diverse patients.

OBJECTIVE: The aim of the study was to assess the impact of systematic use of the DSM-IV-TR cultural formulation on diagnoses of psychotic disorders among patients of ethnic minority and immigrant backgrounds referred to a cultural consultation service (CCS) in Canada.
METHODS: The study entailed a review of medical records and case conference transcripts of 323 patients seen in a ten-year period at the CCS to determine factors associated with change in the diagnosis of psychotic disorders by the CCS. Logistic regression analysis was used to identify variables associated with changes in diagnosis.
RESULTS: A total of 34 (49%) of the 70 cases with an intake (referral) diagnosis of a psychotic disorder were rediagnosed as nonpsychotic disorders, whereas only 12 (5%) of the 253 cases with an intake diagnosis of a nonpsychotic disorder were rediagnosed as a psychotic disorder (p<.001). Major depression, posttraumatic stress disorder (PTSD), adjustment disorder, and bipolar affective disorder were the common disorders diagnosed with use of the cultural formulation. Rediagnosis of a psychotic disorder as a nonpsychotic disorder was significantly associated with being a recent arrival in Canada (odds ratio [OR]=6.05, 95% confidence interval [CI]=1.56-23.46, p=.009), being nonblack (OR=3.72, CI=1.03-13.41, p=.045), and being referred to the CCS by nonmedical routes (such as social work or occupational therapy) (OR=3.23, CI=1.03-10.13, p=.044).
CONCLUSIONS: Misdiagnosis of psychotic disorders occurred with patients of all ethnocultural backgrounds. PTSD and adjustment disorder were misidentified as psychosis among immigrants and refugees from South Asia. Studies are needed that compare clinical outcomes of use of cultural consultation with outcomes from use of other cultural competence models.