Pai 2002.

Methods	Allocation: randomised. Blindness: double blind, a placebo with an identical appearance to the risperidone, but unclear who is blinded. Duration: 12 weeks. Settings: not stated. Design: parallel.
Participants	Diagnosis: schizophrenia (DSM‐IV). N = 50*. Age: mean ˜ 50.2 years, SD ˜ 9.6 years. Sex: male = 20 and female = 10. Length of illness: mean 11.86 years, SD 10.1 years. Inclusion criteria: age between 18 and 65 years, maintenance on conventional antipsychotics for more than 1 year with an equivalent dosage of less than 200 mg/day of chlorpromazine, BPRS total scores of less than 20, and no record of any violent or aggressive behavior within the last 6 months, to minimise the risk of psychotic exacerbation after withdrawing antipsychotics. Exclusion criteria: comorbidity of organic mental disorder or major physical illness, ever being prescribed any atypical antipsychotic, and neuroleptic depot administration within the last 6 months.
Interventions	1. Risperidone: titration period 6 weeks from 2 mg/d to 6 mg/d, then with fixed dosage of 6 mg/d for the remaining 6 weeks, N = 22. 2. Placebo: titration period 6 weeks from 2 mg/d to 6 mg/d, then with fixed dosage of 6 mg/d for the remaining 6 weeks, N = 20.
Outcomes	Mental state: BPRS. Leaving the study early. Global state: needing additional medication; CGI. Adverse effects: ESRS‐parkinsonism score, ESRS‐dystonia score, AIMS total score, concomitant with benzodiazepine, concomitant with antiparkinsonism drug. Unable to use: The number of participants leaving the study early in each group was not reported. Change score of ESRS, change score of AIMS. Change scores were not used, as endpoint scores of the same scales were available.
Notes	*2 of the references reported N = 50, 1 reference reported N = 49. We assume N = 50 in this review.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised, no further information: Quote: "subjects were randomly assigned to the risperidone or placebo groups". (Bai 2003, p1343)
Allocation concealment (selection bias)	Unclear risk	Not stated.
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: "double blind, a placebo with an identical appearance to the risperidone, but unclear who is blinded." (p1343)
Incomplete outcome data (attrition bias) All outcomes	High risk	42 participants completed the 12‐week study and 7 participants withdrew. 4 participants left the study early due to psychotic symptom exacerbation, another 3 participants withdrew due to a medical condition.
Selective reporting (reporting bias)	Low risk	All the measured outcomes were reported.
Other bias	Low risk	None obvious.