Chouinard 1977.

Methods	Allocation: randomised. Blindness: double. Duration: 12 weeks, preceded by 2 weeks fixed daily dose of 125 mg chlorpromazine. Setting: single‐centre, Hôpital St‐Jean‐de‐Dieu, Montréal and Hôpital St‐Charles, Joliette (Canada).
Participants	Diagnosis: chronic schizophrenia. N = 54. Age: mean ˜ 46 years. Sex: 27 F, 27 M. History: all participants previously receiving antipsychotic medication (not specified); mean hospitalisations 13.35. Included: age 20 to 60 years; primary diagnosis of schizophrenia. Excluded: organic heart disease; physical illness/ chronic or acute brain syndrome; IQ lower than 70; alcoholism; epilepsy; drug addiction; electrolyte abnormalities. Consent: all participants gave informed consent after purpose of the study and possible side effects had been explained.
Interventions	1. Perphenazine (Trilafan) 20mg/ day, n = 18. 2. Placebo: 5 tablets a day, n = 18. [3. Perphenazine 20 mg/day and amitriptyline 125 mg/day, n = 18 ‐ not included in data and analysis, combined with anti‐depressant].
Outcomes	Leaving the study early. Adverse events: use of antiparkinsonian medication. Physical tests: ECG abnormalities (primary outcome). "Intensified psychopathological condition" ‐ resulting in hop.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Random ‐ no further details.
Allocation concealment (selection bias)	Unclear risk	No further details.
Blinding (performance bias and detection bias) All outcomes	Low risk	Double: ECG readings (primary outcome) taken by cardiologist unaware “as to factors under study” (p.952). Drugs were administered in identically‐appearing tablets.
Incomplete outcome data (attrition bias) All outcomes	High risk	Follow‐up ‐ N = 38 (70%), with equal amount of males (n = 19) and females (n = 19) remaining. N = 13 placebo participants were excluded from study because of intensified psychopathological condition resulting in hospitalisation or chlorpromazine use. N = 1 perphenazine and n = 2 perphenazine‐amitriptyline participants were hospitalised and excluded from study.
Selective reporting (reporting bias)	Low risk	None detected.
Other bias	Unclear risk	Funding: unclear. Raters: not stated to be independent of treatment.