Long-term outcome with clozapine: comparison of patients continuing and discontinuing treatment

The aim of this naturalistic study was to compare the outcome of patients who continued on clozapine with that of those who discontinued treatment with this drug. Data from 113 patients who commenced clozapine between January 1990 and June 1995 were available for analysis. The main outcome measures were hospitalization status at each anniversary since starting treatment, and the proportion of time spent in hospital by the survey endpoint. On average, patients had been ill for 11.8 years (SD 7.9) and had spent a total of 3.5 years (SD 5.3) in hospital, before treatment with clozapine. The mean duration of follow-up was 2.5 years (SD 1.25, range: 0.32-5.5), by which time 39 patients (35%) had discontinued clozapine. Patients who remained on clozapine (n = 74) were no more likely to have been discharged from hospital than those who discontinued it (n = 39) by the end of the first, second or third year of treatment (p < 0.05). Recent reports of the cost-effectiveness of clozapine treatment should be interpreted with caution.