Thompson 2008.

Methods	Allocation: cluster‐randomised trial. Blindness: not blind. Duration: five months.
Participants	Diagnosis: severe mental disorders. N of clusters: 19 adult psychiatric units. N of participants: 480. Sex: 63.6% M (experimental group); 50.0% M (control group). Mean age, years: 42.2 (experimental group); 42.4 (control group). Setting: South‐West England.
Interventions	1. Multifaceted implementation strategy. The first phase of the implementation strategy involved a 30‐minute structured personal visit to consultant psychiatrists by a specially trained clinical psychiatric pharmacist. The structure of the visit was based on the social marketing principles of 'academic‐detailing'. For the second part of the intervention, a workbook for both doctors and nurses was developed. This contained educational materials and specific cognitive techniques to challenge polypharmacy. The cognitive behavioural techniques were based on the principles of reducing risk‐taking behaviours. The workbook was distributed to all ward doctors and nurses. A range of strategies were offered as alternatives to polypharmacy. A 'booster' pamphlet was sent eight weeks after distribution of the workbook. For the third part of the intervention, a medication chart reminder system was developed. Ward pharmacists applied removable reminder stickers to medication charts when participants were prescribed more than one antipsychotic. Target of the intervention: doctors and nurses. 2. Passive guideline dissemination: disseminated to all doctors and nurses.
Outcomes	Practitioner impact: antipsychotic polypharmacy (from participants' medication charts).
Notes	Mean number of participants per cluster (m): 25.3. Intraclass coefficient (ICC): 0.027. Design effect: 1.65.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random numbers were generated by one of the study authors using a calculator's random number generator function.
Allocation concealment (selection bias)	Low risk	Allocation was performed by one of the study authors, who was blind to the identity of the units.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Quote: "Participants were potentially aware of which group (control or intervention) they were allocated to due to the nature of the intervention".
Incomplete outcome data (attrition bias) All outcomes	Low risk	All randomly assigned units (clusters) were included in the analysis. The study consisted of two cross‐sectional surveys, one carried out at baseline and the second at follow‐up. The primary outcome was polypharmacy at follow‐up (cross‐sectional nature of the primary outcome measure).
Selective reporting (reporting bias)	Low risk	All outcome measures reported in the Methods were included in the analysis and reported in the Results.
Other bias	Unclear risk	Quote: "Patients were younger, more likely to be male and detained under the Mental Health Act in the intervention arm".