Eighty-four studies were included in the review (n=2,079 patients), including thirty-three prospective studies (n=1,880 patients) and fifty-one case reports or retrospective studies (n=199 patients). Only eleven prospective studies were randomised controlled trials (RCTs).
Typical antipsychotics: One double-blind RCT reported that haloperidol and chlorpromazine were associated with an improvement of delirium symptoms in patients with medically hospitalised AIDS, but lorazepam did not improve symptoms. One RCT reported that, compared with somatic treatment, haloperidol and olanzapine were significantly associated with an improvement in the rate of response (improvement of symptoms) and a reduction of the delirium severity in patients with senile dementia.
Atypical antipsychotics: One prospective study reported that risperidone improved cognitive and behavioural symptoms of delirium. One prospective study reported that risperidone was effective in 90% of 64 patients with delirium. One RCT showed that there were no significant differences in the response rate between the haloperidol and risperidone groups. Four studies showed that olanzapine and haloperidol had a similar effect of improving delirium symptoms. One retrospective study, one prospective study and one case report reported that quetiapine was effective in treating delirium. One RCT showed that quetiapine significantly improved noncognitive symptoms of delirium compared with placebo. One RCT reported similar responses to quetiapine and amisulpiride therapies.
Typical antipsychotics: One RCT reported that haloperidol prophylaxis reduced the postoperative incidence of delirium in patients undergoing gastrointestinal surgery. One RCT showed that, compared with placebo, haloperidol significantly reduced severity and duration of delirium in patients at high risk for developing delirium after hip surgery, but there was no significant difference in the incidence of delirium.
Atypical antipsychotics: Two RCTs showed that prophylaxis with risperidone or olanzapine significantly reduced the incidence of delirium compared with placebo in patients that had undergone cardiac or orthopaedic surgery .
Results of assessing cholinesterase inhibitors and adjunctive agents for treating or preventing delirium were also reported.
For adverse events, sedation might be a problem with olanzapine use. One retrospective study reported that atypical antipsychotics were not significantly associated with an increased risk of stroke in elderly patients compared with typical antipsychotics. One large retrospective study reported that typical antipsychotics were significantly associated with a higher risk of mortality in elderly patients compared with atypical antipsychotics.