The effectiveness of clozapine: a controlled, population-based, mirror-image study [Abstract]

A retrospective cohort study, with a mirror-image design, was used to measure inpatient service utilisation in 63 consecutive patients started on clozapine from a geographical catchment area, compared to a control group matched for previous inpatient service use. An intent to treat analysis, including those patients (n=28), who discontinued clozapine during the study period, showed a significant reduction in number of admissions and total time spent in hospital in the 2 years following clozapine initiation, compared to the previous 2 years and to the follow-up period inthe control group. This translated into a reduction of £7,300 in hospitalisation costs per patient started on clozapine, over the 2-year period. In those patients who continued clozapine treatment for the whole of the 2-year period, there was a two-thirds reduction in number of admissions and total time spent in hospital, compared to no change in the clozapine discontinuers. These findings suggest that clozapine is a clinically and cost effective intervention for severe schizophrenia in routine NHS settings.