Treatment for delirium with risperidone: results of a prospective open trial with 10 patients.

Delirium is a common psychiatric illness among medically compromised patients. There is an increasing opportunity to use atypical antipsychotics to treat delirium. The effects of these drugs on delirium, however, the most appropriate way to use them, and the associated adverse effects remain unclear. To clarify these points, a prospective open trial on risperidone was carried out in 10 patients with delirium. At a low dose of 1.7 mg/d, on average, risperidone was effective in 80% of patients, and the effect appeared within a few days. There were no serious adverse effects. However, sleepiness (30%) and mild drug-induced parkinsonism (10%) were observed; the symptom of sleepiness was a reason for not increasing the dose. One patient responded to a dose as low as 0.5 mg/d, so it is recommended that treatment start at a low dose, which may then be increased gradually. This trial is a preliminary open study with a small sample size, and further controlled studies will be necessary.