In Reply

SIR: We grant the methodological shortfalls of our study¹ that Drs. Friedman and Ott have pointed out. Nevertheless, all the patients in our study had idiopathic Parkinson's disease (IPD), dementia, psychotic features, and behavioral disturbances that necessitated psychiatric admission. At the time of our data base study, risperidone was the only option we had other than the typical antipsychotics and clozapine, which was not an option because of the risk of adverse reactions and its prohibitive cost for these nursing home patients. Furthermore, there was little in the scientific literature to guide the clinician.

It seemed to us that clinically, these patients' psychotic features and behavioral problems improved and their IPD did not noticeably worsen. We tried to quantify those observations by using our data base instruments. In Drs. Friedman and Ott's own article there was 1 case with similar good outcome using risperidone.²

As far as risperidone not being an atypical antipsychotic, Leyson et al.³ reported, “Risperidone bound to 5-HT_2A receptors with 20 times greater affinity than clozapine and 170 times greater affinity than haloperidol.… A conspicuous property of risperidone, not seen for the other compounds, was the shallow occupancy curve at the D₂ receptors in the striatum and mesolimbic brain area.”

It is puzzling that Drs. Friedman and Ott would want to restrict clinicians' antipsychotic options in patients suffering from IPD and psychosis when sound methodological, prospective studies of all the atypical antipsychotics have yet to be performed.