To the Editor: It is well known that antipsychotic medications may contribute to weight gain when initiated for the treatment of schizophrenia, and in the brief report by Allison and his colleagues in the April issue we at last have a description of the effects that weight gain might have on patients' quality of life (1). These investigators distributed a self-administered questionnaire through chapters of the National Alliance for the Mentally Ill to patients with schizophrenia to assess six-month weight trends.
A limitation not mentioned in the authors' discussion relates to the differential weight gain effects and time courses of the various antipsychotics. A previous study by Wirshing and associates (2), as well as other studies, demonstrated that atypical antipsychotics, especially clozapine and olanzapine, produce a greater net weight gain than risperidone and conventional antipsychotics. In addition, patients receiving clozapine and olanzapine continued to gain weight over a longer period than patients taking other antipsychotics. This point is especially confounding for the study by Allison and colleagues, because in the Wirshing study the mean duration of treatment with atypical antipsychotics was 33.9±28.6 months, compared with a mean duration of 123.2±91 months for patients receiving conventional antipsychotics. Longer treatment with conventional antipsychotics may place patients on a weight plateau after an initial weight gain, whereas patients who have recently started atypical agents are still in an acute weight gain phase. If this is the case, then the study by Allison and colleagues may have detected the difference between the relative psychological and physical well-being of patients with schizophrenia whose illness is well managed with a long-term regimen and the distress of patients who are adjusting to a new regimen—or who may have had frequent medication changes for other side effects before therapeutic dosages were achieved.
Furthermore, although Allison and colleagues acknowledge the importance of considering compliance issues, it is not clear from their report whether there was any discontinuation, dosage reduction, or switching of medications because of weight gain during their study, which would certainly have explained those patients' poorer quality-of-life scores.
Compliance among patients with schizophrenia is clearly a potential target for improvement, and more work like that of Allison and colleagues, elucidating the obstacles to adequate compliance with antipsychotic medication regimens, will be very helpful in tailoring psychotherapeutic approaches to patients' needs.
Dr. Fetter is a resident in the departments of psychiatry and internal medicine at Dartmouth Hitchcock Medical Center in Lebanon, New Hampshire.