Bai 2003.

Methods	Allocation: "randomly assigned", not described Blindness: "double blind", partially described Design: parallel groups Setting: inpatients, Taiwan Duration: 12 weeks
Participants	Diagnosis: schizophrenia with persistent severe TD (DSM IV, Kane criteria) N = 49 randomised, 42 completed Age: 50.2 (SD 9.7) years Sex: 28 men and 14 female History: maintenance on conventional antipsychotics for > 1 year with an equivalent dosage of < 200 mg/d of chlorpromazine; duration of TD not reported
Interventions	After a 4‐week washout period with all original conventional antipsychotics discontinued: 1. Risperidone: started at 2 mg/d and increased, with a 2‐mg increase every 2 weeks, to 6 mg/d over 6 weeks; then maintenance dose 6 mg/d for 12 weeks. N = 22 2. Placebo: placebo for 12 weeks. N = 20 Concomitant medication included benzodiazepines (86%‐90%) and antiparkinsonism drugs (50%‐86%)
Outcomes	TD symptoms: AIMS Adverse effects: extrapyramidal symptoms (parkinsonism) (ESRS) Adverse effects: dystonia (ESRS) TD symptoms: clinical efficacy (decrease in AIMS of 3 or 4 = responder) BPRS
Notes	Sponsorship source: supported by Janssen‐Cilag Taiwan, Johnson & Johnson Taiwan Ltd
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"subjects were randomly assigned to the risperidone or placebo groups", further details not reported
Allocation concealment (selection bias)	Unclear risk	Allocation concealment not reported
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"double‐blind" "A placebo with an identical appearance to the risperidone dose was prescribed for the placebo group using the same dose schedule."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"The TD condition was evaluated blindly by a psychiatrist with the Abnormal Involuntary Movement Scale (AIMS) every 2 weeks"
Incomplete outcome data (attrition bias) All outcomes	Low risk	"Forty‐two patients completed the 12‐week study and 7 subjects withdrew. Four subjects dropped out due to psychotic symptom exacerbation (2 subjects during the washout period: 1 subject in the placebo group and 1 subject in the risperidone group). Another 3 subjects withdrew due to a medical condition (infectious disease, heart condition, and lung carcinoma)."
Selective reporting (reporting bias)	Unclear risk	Unclear if all pre‐defined outcomes were reported. A protocol is not available for verification.
Other bias	Low risk	The study seems to be free of other sources of bias.