Eligible studies were randomised, double-blind, placebo-controlled trials that used an intention-to-treat analysis. Articles published before 1984 were excluded if they had fewer than 100 patients. Trials needed to compare two antipsychotics or an antipsychotic with placebo. All drugs were to be administered orally. Trials needed to assess, as a primary outcome, the effect of treatment on behavioural and psychological symptoms of dementia (diagnosed according to international criteria) or on adverse events.
Mean age of participants was 80 years. Most had moderate to severe dementia; mean scores on Mini-Mental State Examination ranged from 5.5 to 15.2. Nine per cent lived in the community. Trials evaluated the antipsychotics haloperidol, tiapride, risperidone, loxapine, perphenazine, quetiapine and olanzapine. Trial duration was three to 16 weeks. Adverse events were assessed using questionnaires and physical performance tests; in some trials spontaneous reporting was used.
One researcher screened titles and abstracts of potentially eligible studies. Two reviewers were involved in the screening of full papers and resolved disagreements through discussion.