The Clozaril Patient Monitoring Service (CPMS) does not record which patients are being treated under the Mental Health Act 1983 and we are therefore unable to say what proportion of patients in our cohort were compulsorily detained. We are not aware of any studies regarding second opinions from the Mental Health Act Commission in patients undergoing rechallenge with clozapine but would be interested to hear of any.

We have re-examined our data to determine whether patients were more or less likely to develop dyscrasia on rechallenge if they had a history of an alternative explanation for the first episode of dyscrasia. Out of 53 patients in the cohort, 25 had an alternative explanation for the first episode and 6 of these (24%) developed a second episode on rechallenge. Out of the 28 patients with no alternative explanation for the first episode of dyscrasia, 14 (50%) experienced dyscrasia on rechallenge. The difference was not significant (P=0.05914). The relative risk of 2.08 indicated that patients with no alternative explanation may be twice as likely to have a second episode of dyscrasia on rechallenge as those with an alternative explanation, but the 95% confidence interval was 0.98-6.2. We must stress that alternative explanations for dyscrasia may not always be reported to the CPMS, therefore these figures may not represent the true picture and this aspect of our work should be interpreted with caution.