3. Suggested design for a trial.

Methods	Allocation: randomised, clearly described, concealed. Blindness: double, described and tested. Duration: 2 weeks.
Participants	Diagnosis: thought to have psychoses. N = 300.* Age: any. Sex: both. History: acutely ill, aggressive.
Interventions	1. Haloperidol IM: dose flexible within recommended limits. N = 150. 2. Benzodiazepine IM: dose flexible within recommended limits. N = 150.
Outcomes	All outcomes are grouped by time: by 30 minutes, up to two hours, up to four hours, up to 24 hours and finally over 24 hours.  Tranquillisation or asleep (measured at 30 minutes, 2 hours, 4 hours and 24 hours). Mortality. Specific behaviours ‐ self‐harm, including suicide, injury to others, aggression. Global outcomes ‐ overall improvement, use of additional medication, use of restraints/seclusion. Service outcomes ‐ duration of hospital stay, re‐admission. Mental state ‐ no clinically important change in general mental state. Adverse effects ‐ clinically important adverse effects. Leaving the study early ‐ why. Economic outcomes.
Notes	* Powered to be able to identify a difference of ˜20% between groups for primary outcome with adequate degree of certainty.

IM: intramuscular