Adelson 1962.

Study characteristics
Methods	Type: clinical Design: parallel Objective: to investigate the effectiveness of 4 phenothiazine derivatives Treatment duration: 4.5 months Follow‐up duration (including treatment duration): 8 months Washout between cross‐over periods: NA
Data	Country: USA Condition: schizophrenia Number of people randomised: 48 to each placebo group (288 in total) Number of people analysed: 48 in each placebo group (288 in total)
Comparisons	Active placebo: scopolamine (maximum daily dose 1.50 mg) and chlorprophenpyridamine maleate (maximum daily dose 30 mg) Standard placebo: lactose Experimental intervention: 4 phenothiazines (doses in brackets are maximum daily doses): chlorpromazine (3000 mg), triflupromazine (750 mg), prochlorperazine (450 mg), perphenazine (240 mg) Administration: oral
Outcomes	Participant‐reported outcome: none Observer‐reported outcome: MRSPP (Multidimensional Scale for Rating Psychiatric Patients, Hospital Form; also called Lorr scale); assessed at 4 months, 5.5 months (earliest post‐treatment assessment), and 8 months (latest follow‐up) Harm outcome: number of side effects Co‐intervention outcome: none
Terminology for active placebo	"Active placebo" a priori
Scores and unpleasantness of the active placebo	Adequacy: 3 Risk of therapeutic effect: 2 Unpleasant/neutral/pleasant: unpleasant
Funding and conflicts of interest	Non‐industry funding, but drugs supplied by the industry. Conflicts of interest not reported.
Notes	15 people dropped out and were replaced with randomly selected substitutes: 2 on active placebo and 2 on inactive placebo (i.e. keeping number of participants in the groups at 48).
Risk of bias
Item	Authors' judgement	Support for judgement
Free from risk of bias arising from the randomisation process	Unclear	Stagger system. Allocation concealment not clearly described, but assignment carried out by a person not involved in the study. Study staff had no knowledge of the assignment. No indication of baseline differences. Replacements brought in for dropouts (n = 15, 2 for each placebo control intervention).
Free from risk of bias in selection of the reported result All outcomes	Unclear	No information.