Litz 2012.

Methods	Design: Randomised, double‐blind, placebo controlled trial Study duration: 6 weeks Follow‐up: 6 months Country: USA
Participants	Sample size: 26 adult participants eligible and agreed to participate Recruitment: unclear Inclusion criteria ‐ diagnostic classification criteria: primary diagnosis of PTSD, DSM‐IV Inclusion criteria ‐ rating scales: Structured Clinical Interview (SCID‐IV) Included disorders: PTSD and co‐morbid diagnoses Co‐morbidities: MDD (n = 7), alcohol use (n = 5), SAnD (n = 2) Gender: 100% male Mean age: 32.19 years (SD 9.31 years) Ethnicity: 76.9% White, 15.4% Black, 3.% Hispanic, 11.18% Pacific Islander, 3.8% Haitian Pharmacotherapy during the study: Naturalistic prescribing allowed
Interventions	Intervention: Participants received 6‐weekly sessions of exposure therapy and 50 mg DCS administered 30 minutes prior to sessions 2 to 5 (n = 13) Comparison: Participants received 6‐weekly sessions of exposure therapy and placebo pill administered 30 minutes prior to sessions 2 to 5 (n = 13) Therapists: Therapists were doctoral‐level clinicians with previous experience and training in CBT for anxiety disorders
Outcomes	Response; withdrawals; anxiety: CAPS; co‐morbid depression: BDI‐II; adverse events
Notes	Funding from Industry: No, this randomised controlled trial was funded by the VA as part of a joint VA/NIMH solicitation for R‐34 type PTSD trials Medication supplied by industry: No Any authors work for industry: Yes Study ID: NCT00371176
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer generated randomisation list. Randomisation was blocked and stratified based on PTSD scores (CAPS scores < 75 or > 75)
Allocation concealment (selection bias)	Low risk	The randomisation allocation sequence was implemented by a pharmacist (not part of the research team) who assigned participants to conditions according to a computer generated randomisation list
Blinding of participants and personnel (performance bias) All outcomes	Low risk	All research team members, therapists, assessors, and participants were blind to condition
Blinding of outcome assessment (detection bias) All outcomes	Low risk	All research team members, therapists, assessors, and participants were blind to condition
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Six participants were lost to follow‐up. Insufficient reporting of attrition to permit judgement
Selective reporting (reporting bias)	High risk	Quality of Life Enjoyment and Satisfaction Questionnaire, an outcome relevant for this review, was pre‐stated in the protocol but the results not reported
Other bias	Low risk	No sources of other bias were identified