Chen 1995.

Methods	Allocation: "cross over randomized trial". Blinding: double‐blind with adequate description. Duration: 4 weeks. Design: cross‐over. Setting: inpatients, China. Raters: blinding of raters not reported.
Participants	Diagnosis: Antipsychotics‐induced tardive dyskinesia. N = 20*. Sex: 12 M, 8 F. Agemean 34.86 (SD 7.82) years old. Duration of TD: mean 3.52 (SD 2.38) years.
Interventions	1. Bromocriptine Group: at first phase of the trial, the participants received bromocriptine, 1 capsule each time, twice per day for 4 weeks. The second phase was a 2‐week washout period. At the third phase of the trial, the participants received placebo for 4 weeks. N = 10.* 2. Placebo Group: at first phase of the trial, the participants received placebo for 4 weeks. The second phase was a 2‐week washout period. At the third phase of the trial, the participants received bromocriptine, 1 capsule each time, twice per day for 4 weeks. N = 10.* All participants received stable doses of antipsychotics before and during the study. Other concomitant medication was not reported.
Outcomes	Leaving the study early. Unable to use (data from first phase before cross‐over not reported separately) ‐ Abnormal Involuntary Movement Scale (AIMS). Clinical response of TD.** Adverse events: dizziness, nausea. Study authors were contacted but no more information was received.
Notes	*sequential test method was used; when the 10th participants completed the trial, a significant difference was detected, so they terminated enrolling participants. **clinical improvement defined as the decrease rate of AIMS score ≥ 20%. Data extracted by Sai Zhao from Chinese language report.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"cross over randomized trial"; no further details reported.
Allocation concealment (selection bias)	Low risk	"the interventions were coded as intervention A or B by the researcher in pharmacy".
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"double blind study, the interventions were coded as intervention A or B by the researcher in pharmacy" "Participants and personnel did not know the allocation result". The 2 drugs were contained in capsules with same appearance. Blinding of participants and key study personnel ensured.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants completed the study.
Selective reporting (reporting bias)	Unclear risk	Unclear if all predefined outcomes have been reported. A protocol is not available for verification.
Other bias	Low risk	The study seems to be free of other sources of bias.