Zahradnik 2009.

Methods	RCT.
Participants	Adult patients between 18 to 69 years old admitted to surgical or gynaecological wards in Germany who had consumed prescription drugs (PD) with addiction potential for more than 60 days in last 3/12 or fulfilled DSM IV criteria for PD dependence or abuse. Drugs considered to have addiction potential; opiates, sedative‐hypnotics or caffeine. 39 participants; 20 participants in intervention group and 19 participants in control group.
Interventions	Intervention group: MI. One counselling session using MI in hospital lasting 30 to 45 minutes. Four weeks later one counselling session of MI by telephone including assessment of core constructs of cycle of change (readiness to change) and designed individualised written intervention on basis of this assessment which was fed back by letter sent at 8 weeks after first intervention targeted at self‐efficacy and maintaining changes. Advised to seek help of GP or medical specialist in reducing medication. Control group: Information booklet about problematic prescription drug use.
Outcomes	Self‐reported BZD use as measured in defined daily doses at baseline and at 3‐month follow‐up.
Notes	Additional data supplied by author. Follow‐up paper with 12‐month follow‐up Otto 2009. Funding source: The German research network EARLINT (EARly substance use INTervention) of the German Federal Ministry of Health (Grant: 15 02/68661). Declaration of interest: None.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation not reported.
Allocation concealment (selection bias)	High risk	No concealment as randomised wards known to investigators.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No objective measures used.
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding or incomplete blinding, and the outcome is likely to be influenced by lack of blinding.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No objective measures used.
Blinding of outcome assessor (detection bias) subjective outcomes	Low risk	"A blinded personal interview was conducted by staff who had no contact with the patient prior to the outcome assessment that was conducted mainly by telephone".
Incomplete outcome data (attrition bias) All outcomes	Low risk	ITT analysis performed.
Selective reporting (reporting bias)	Low risk	The study protocol is not available but the published reports include all expected outcomes, including those that were pre‐specified in the methods section.