Prevalence of treatment-resistant psychoses in the community: A naturalistic study

Treatment-resistant schizophrenia (TRS) is a major cause of disability. Clozapine is currently the only antipsychotic medication licensed for its treatment. However, the rate of treatment resistance among outpatients with schizophrenia or other psychoses, and the rate of use of clozapine among them, is not known.

The aims of this study are (a) to determine the point prevalence of treatment-resistant psychosis in a community sample, and (b) to determine the number of patients with TRS who have never had a clozapine trial.

Clinico-demographic data were extracted from the case notes for 202 patients from two community mental-health teams.

We found that 56% (99/176) had a diagnosis of TRS, and 52% (51/99) of these patients had never been treated with clozapine. Patients of non-white ethnicity were less likely to have had a clozapine trial (p=0.009). The point prevalence of treatment resistance within the bipolar affective disorder sample was 19% (5/26).

These findings suggest that TRS is common in the community mental-health team, and a large proportion of these patients have not received clozapine. These findings indicate that identifying and treating treatment resistance should be a focus of community services for schizophrenia.