Ten Wolde 2008.

Methods	RCT.
Participants	695 chronic BZD users attending attending their GP in the Netherlands. 228 participants in intervention group 1; 256 participants in intervention group 2 and 211 participants in control group. After 12 months 187 participants were lost to follow‐up, thus giving a total of 508 participants: 163 participants in the intervention group 1; 186 participants in intervention group 2 and 159 participants in control group.
Interventions	Intervention group 1: Single tailored letter. The single tailored letter intervention consisted of one letter of five to six pages of information (approximately 1200 words) in which all of three psychological determinants were addressed. The information was designed to: (i) increase the perceptions of the positive outcome expectations of discontinuing BZD use (e.g. it was argued that patients may function better cognitively and may evaluate themselves more positively); (ii) lower the perceptions of the positive outcome expectations of the use of BZDs (by explaining the development of tolerance and a possible placebo effect); and (iii) increase self‐efficacy expectations with regard to discontinuing usage (by offering several skills to reach abstinence, such as making a plan to cut down BZD use and by offering alternatives in order to cope with worrying thoughts). Intervention group 2: The multiple tailored letter intervention consisted of three letters of about three pages each (approximately 400 words), sent at intervals of 1 month. In the multiple tailored intervention, the first tailored letter was designed to increase the perceptions of the positive outcome expectations of discontinuing BZD usage and to lower the perceptions of the positive outcome expectations of the use of BZDs. The second tailored letter was designed to increase self‐efficacy expectations with regard to discontinuing usage, while the content of the third letter provided more skills for discontinuing usage, or provided a summary of the information in the first two letters, depending on the individual needs detected in the third assessment. In addition, in the introduction of the second and third letters, participants were provided with progress feedback. Individual changes in BZD use were mentioned. Control group: Standard letter from GP outlining the disadvantages of BZD use and advising to quit use of BZDs. The letter consisted of approximately 200 words.
Outcomes	Self‐reported BZD usage at baseline and 12 month follow‐up.
Notes	Review group took the decision to examine intervention 1 (single letter) versus GP letter 163 participants in intervention group 1 and 159 participants in control group. Reported figures are based on the 12 month data. Funding source: Dutch Council for Health Insurance. Declaration of interest: Not reported.
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	GPs could select out patients who had severe comorbidity or psychological problems.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No objective measures were 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 were used.
Blinding of outcome assessor (detection bias) subjective outcomes	High risk	No blinding of outcome assessment, and the outcome measurement is likely to be influenced by lack of blinding.
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.