Morton 1968.

Methods	Allocation: randomly assigned. Blinding: double, identical capsule given by the hospital pharmacist. "no one concerned with the care of patients knew which patients were started on placebo". Duration: 6 months.
Participants	Diagnosis: schizophrenia. N=40 (12 to relevant interventions). Age: 25‐55 yrs. Sex: all male. History: in hospital >2 yrs, on chlorpromazine >18 months, maintenance doses of tranquillizer had been administered for at least 18 months.
Interventions	1. Chlorpromazine cessation: placebo. N=6. 2. Trifluoperazine cessation: placebo. N=14. 3. Chlorpromazine continuation: (dose not reported). N=6 4. Trifluoperazine continuation: (dose not reported). N=14.
Outcomes	Relapse. Mental state: Wing scale. Unable to use ‐ Behaviour change: WPRS (no usable data).
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear