Study designs of evaluations included in the review
Double-blind randomised controlled trials (RCTs). Follow-up ranged from 4 to 12 weeks. An intention-to-treat (last observation carried forward) analysis was performed.
Specific interventions included in the review
Risperidone (fixed dosage of 4mg/day; mean dosage range 6 to 12.0mg/ day), conventional neuroleptics (haloperidol (fixed dosage 10-20 mg/day; mean dosage range 9.2 to 10.3mg/day) zuclopenthixol (mean dosage 38.0mg/day) and perphenazine (mean dosage 28.0mg/day)) or placebo. Studies that included the active control drug haloperidol at doses that exceeded 20mg/day were excluded. In dose finding trials only one of the fixed doses used was considered to avoid statistical problems with homogeneity.
Participants included in the review
Patients with chronic schizophrenia as measured by DSM-III-R criteria (see Other Publications of Related Interest). The mean age range was 34 to 38 years. The total male/female ratio was 624:287.
Outcomes assessed in the review
Only studies that assessed efficacy and risk of treatment by means of the Positive and Negative Syndrome Scale (PANSS) and the Extrapyramidal Symptom Rating Scale (ESRS) were included in the review. The PANSS scores on three subscales (positive symptoms, negative symptoms and general psychopathology) which were included separately in the review. Studies were also required to provide information on patients' use of antiparkinsonian drugs. Treatment of efficacy in included studies was assessed by several scales including the PANSS, the Brief Psychiatric Rating Scale, and the Clinical Global Improvement Scale. Treatment safety was also assessed by questionnaire on adverse events and patients' spontaneous reports of adverse events.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection.