Silverstone 1984.

Methods	Randomisation: “randomly allocated”. Blinding: double‐blind. Duration: 28 days. Design: parallel. Location: not indicated. Setting: inpatients.
Participants	Diagnosis: acute schizophrenia. N = 22. Gender: 11M, 11F. Age: mean 38.5 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: fixed/flexible dose: not indicated, dose range: not indicated, mean final dose: 22.2 mg/day. N = 12. 2. Pimozide: fixed/flexible dose: not indicated, dose range: not indicated, mean final dose 21.6 mg/day. N = 10. Rescue medication: i.m. chlorpromazine “when the clinical situation demanded”. “Extrapyramidal side effects were treated with procyclidine. Temazepam or nitrazepam was prescribed if night sedation was required.”
Outcomes	Examined: Leaving the study early due to any reason. Adverse effects: dystonia, tremor, use of antiparkinson medication, hypotension, sedation. Unable to use: Mental state general: Montgomery Rating Scale (MRS) (no SDs available and no imputation method could be applied). Leaving the study early due to adverse effects (data only for the haloperidol group available).
Notes	Study participants were “22 patients with acute schizophrenic illness” (18 completers). 8 participants with first episode.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	“Randomly allocated”. No further details.
Allocation concealment (selection bias)	Unclear risk	No further details.
Blinding (performance bias and detection bias) (performance bias)	Low risk	“Double‐blind”. “pimozide or haloperidol in matching 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	There were 3 drop‐outs in the haloperidol‐group (25%), and 1 participant left the trial early in the pimozide‐group (10%). The overall‐attrition was 18.2% (4 of 22 participants). Altogether the attrition was moderate. The trial authors provided the results of the completers‐only analysis.
Selective reporting (reporting bias)	High risk	The outcome data were not fully addressed (no SDs for the MRS). No usable data were provided in terms of premature discontinuation of the trial due to adverse effects.
Other bias	High risk	Additional antipsychotic pharmacological treatment with i.m. chlorpromazine was allowed (used in 3 participants).