Cassano 1975.

Methods	Randomisation: “entirely randomised experimental design”. Blinding: double‐blind. Duration: 30 days. Design: parallel. Location: multicentre (Institute of Psychiatry, University of Pisa; Institute of Psychiatry, University of Pavia; Provincial Psychiatric Institutes, Ceremona; S. Lazzaro Psychiatric Institute, Reggio Emilia; Neuropsychiatric Hospital, Teramo; Provincial Neiropsychiatric Hospital, Varese). Setting: inpatients.
Participants	Diagnosis: schizophrenia (paranoid and hebephrenic schizophrenia). N = 76. Gender: “both sexes”, no further details available. Age: mean 38 years. History: duration stable: not indicated, duration of illness: not indicated, number of previous hospitalisations: not indicated, age at onset: not indicated, severity of illness: not indicated, baseline antipsychotic dose: not indicated.
Interventions	1. Haloperidol: flexible dose, dose range: 0.5 to 10.5 mg/day, mean dose: 5mg/day. N = 36 (number of participants included in the analyses, the number of participants randomised to this study group was not indicated). 2. Sulpiride: flexible dose, dose range: 100 mg to 2300 mg/day, mean dose: 1000mg/day. N = 34 (number of participants included in the analyses, the number of participants randomised to this study group was not indicated).   Flexible dose: “The dosage scheme was flexible and individualised according to clinical response and tolerability.” Rescue medication: “an antiparkinson drug (orphenadrine) could be administered in the case of appearance of extrapyramidal signs.” “Each patient received an evening dose of a hypnotic (amobarbital 100mg).”
Outcomes	Examined: Adverse effects: at least one adverse effect, at least one movement disorder, akathisia, use of antiparkinson medication. Unable to use: Clinically important response to treatment: Clinical evaluation of the changes of global symptomatology (no raw data available). Mental state general: Brief Psychiatric Rating Scale (BPRS) (no raw data available). Mental state general: Inpatient Multidimensional Psychiatric Scale (IMPS) (no raw data available). Leaving the study early due to inefficacy of treatment (number of participants randomised to the groups was not indicated). Leaving the study early due to adverse effects (number of participants randomised to the groups was not indicated).
Notes	“wash‐out period of treatment with placebo (2‐7 days).”
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	“Entirely randomized experimental design”. No further details.
Allocation concealment (selection bias)	Unclear risk	No further details.
Blinding (performance bias and detection bias) (performance bias)	Low risk	“Double‐blind”. “The compounds were contained in indistinguishable capsules.”
Blinding (performance bias and detection bias) (detection bias)	Unclear risk	“Double‐blind”. No further details.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	19 of 76 participants (25%) left the trail early. “In 6 patients, the study was discontinued for reasons totally independent of the treatments; on this basis, they have not been included in the analysis of the results.”
Selective reporting (reporting bias)	High risk	Outcome data reporting was incomplete (no raw data for the BPRS, IMPS, and the clinical evaluation of the changes of global symptomatology). The numbers of participants randomised to each treatment group (haloperidol or sulpiride) were not indicated.
Other bias	Unclear risk	Insufficient information to assess whether an important risk of bias exists.