Letters to the Editor
June 2002

Atypical Antipsychotics and Cognition in Schizophrenia

Author Affiliations

Copyright 2002 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.2002

Arch Gen Psychiatry. 2002;59(6):571-572. doi:

Purdon et al1 have presented, with many qualifications, results from a double-blind randomized trial comparing the cognitive benefits of olanzapine, risperidone, and haloperidol. Studies of this type are important; however, the interpretation of the referenced study requires caution, and the clinical relevance of the data is limited.

In disclosing the increasing interest in slower titration and lower doses of risperidone than were used in the trial, the authors assert that the dosing schema they used was valid because it was consistent with the relevant product monograph and with the doses used in an earlier study.2 Emerging data and clinical practice often lead advances in the standard of care, and changes to product literature lag behind. Also, the study that was cited for setting a dosing precedent was conducted in a refractory population that can be expected to require higher medication doses. A more credible discussion of the aberrantly high doses of risperidone used in the trial would be made by using audited pharmacy data to get a realistic assessment of the average daily doses used in practice at the participating centers.

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