Clozapine and the risk of haematological malignancies – Authors' reply

We thank Peter FJ Schulte and colleagues for their interest in our article. We believe that decisions about the treatment of schizophrenia should be made on the basis of clinicians and patients having access to comprehensive information about the benefits and risks of clozapine. We do not believe information about serious—albeit rare—adverse events should be withheld from patients or caregivers for fear of contributing to non-adherence. Instead, an open and comprehensive discussion about the benefits and risks of treatment provides an opportunity for clinicians to address patient concerns about potential adverse events. This approach includes helping patients to interpret and contextualise information about adverse events obtained from other sources. When providing balanced information about possible adverse events is done well, we do not believe that it leads to clozapine phobia. Providing oral and written information about medications could improve adherence.1 Clozapine was withdrawn worldwide after nine deaths were reported in Finland in July, 1975, due to agranulocytosis and leukaemia.2 Finnish clinicians appear to have succeeded in communicating the benefits and risks of treatment with clozapine because the rate of clozapine use is substantially higher in Finland than in any other country in a study that included 17 countries,3 despite mandatory monthly complete blood count. Our results4 and a meta-analysis from 20195 suggest that clozapine is the safest antipsychotic drug in terms of mortality. Informing clinicians and patients about the overall benefits and risks of treatment, including the mortality benefits, should facilitate even wider use of clozapine. In terms of complete blood count, we did not suggest any procedures deviating from the usual standard practice (ie, the standard risk–benefit assessment) used in other patient populations after the detection of abnormal complete blood count.