Rama Rao 1981.

Methods	Randomisation: “randomly allocated”. Blinding: double‐blind. Duration: 12 weeks. Design: parallel. Location: not indicated. Setting: inpatients.
Participants	Diagnosis: chronic schizophrenia. N = 30. Gender: 30F. Age: mean 60 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: “All patients had been previously stabilised on haloperidol for at least 6 months".
Interventions	1. Haloperidol: fixed/flexible dose: not indicated, dose range: not indicated, mean dose: not indicated (“the patients continued to receive the same dose as before the trial”). N = 15. 2. Sulpiride: fixed dose, dose range: not indicated, mean dose: 1200 mg/day. N = 15.   Rescue medication: “15‐30 mg/day procyclidine was given where necessary”
Outcomes	Examined: Mental state general: Brief Psychiatric Rating Scale (BPRS). Behaviour: Wing’s Ward Behaviour Scale. Leaving the study early due to any reason. Leaving the study early due to inefficacy of treatment. Leaving the study early due to adverse effects. Adverse effects: use of antiparkinson medication.
Notes	Study participants were “30 female patients who had been hospitalised for an average of more than 20 years. All had been diagnosed as suffering from schizophrenia”. Before the randomisation to either haloperidol or sulpiride all participants were stabilised on “the dosage of haloperidol which produced optimum therapeutic response.” The participants randomised to haloperidol “continued to receive the same dose as before the trial.”
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	“Randomly allocated”. “Patients were stratified so that age and baseline morbidity were constant in each group.” No further details.
Allocation concealment (selection bias)	Unclear risk	No further details.
Blinding (performance bias and detection bias) (performance bias)	Low risk	“Double‐blind”. “A double‐dummy technique was used.”
Blinding (performance bias and detection bias) (detection bias)	Unclear risk	“Double‐blind”. “A double‐dummy technique was used.” No further details.
Incomplete outcome data (attrition bias) All outcomes	Low risk	“Three patients were not sufficiently accessible to be rated on the BPRS.” According to the tables in the publication, no participants left the trial early.
Selective reporting (reporting bias)	Unclear risk	The outcomes have been reported in the pre‐specified way with the exception of the adverse effects that were not fully addressed. The study report fails to include results for the primary outcome of the review.
Other bias	High risk	“The patients who received active sulpiride were in fact at a disadvantage compared to the haloperidol group who continued to receive the drug in therapeutically optimum dosage.” The trial authors “feel that a flexible dosage regime could have been even more favourable for sulpiride treatment.”