Koshino 1983.

Methods	Allocation: "randomly allocated", Details not reported. Blindness: "double‐blind," Details not reported Duration: 6 weeks Design: Parallel Setting: Inpatients in a psychiatric hospital in Japan
Participants	Diagnosis: antipsychotic‐induced TD, Schizophrenia N = 28 Sex: Male 16, Female 12 Age: 59.3 (SD: 8.29) History: Duration of TD not reported.
Interventions	1. Dihydrogenated Ergot Alkaloids (6 mg/day, 6 week). N = 14 2. Placebo. N = 14 Concomitant medication not reported.
Outcomes	Tardive dyskinesia: Not clinically improved Tardive dyskinesia: Not any improved Tardive dyskinesia: Simpson scale Tardive dyskinesia: Deterioration Mental state: Not any change in general mental state Adverse effects general Leaving the study general Leaving the study Due to side effect
Notes	Sponsorship source: Dihydrogenated Ergot Alkaloids and placebo tablets supplied by Sandoz Assessed and data extracted by Yusuke Ogawa.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"randomly allocated", Details not reported.
Allocation concealment (selection bias)	Low risk	Randomization was conducted by the third person (outside of the research group). Allocation codes were stored until the end of the study
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	"double‐blind," Details not reported.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	"double‐blind," Details not reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Twenty‐eight patients were admitted to the study, and all of them completed the 4‐week trial.
Selective reporting (reporting bias)	Unclear risk	Unclear if all pre‐defined outcomes were reported. A protocol is not available.
Other bias	Unclear risk	Insufficient information to make a judgement.