Marks 1998.

Methods	Randomised controlled trial
Participants	87 DSM‐IIIR PTSD, various traumas, in the UK
Interventions	10 x 90‐minute sessions of exposure (n = 23) vs cognitive restructuring (n = 19) vs exposure and cognitive restructuring (n = 24) vs relaxation therapy (n = 21) (the three exposure/cognitive‐restructuring groups were combined).
Outcomes	CAPS, IES, BDI, STAI
Notes	Experienced therapists delivered therapy. Treatment adherence was assessed, as was homework compliance.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: The method of sequence generation was not reported.
Allocation concealment (selection bias)	Unclear risk	Comment: There is no mention of any measures taken to conceal allocation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "analyses were also done on end‐point imputed‐scores carrying forward non‐completers last available ratings". Comment: There were drop‐outs from each group: exposure (3) cognitive restructuring (1) exposure and cognitive restructuring (5) and relaxation therapy (1). Reasons for drop‐out were not fully reported.
Selective reporting (reporting bias)	Low risk	Comment: All specified outcomes were reported.
Other bias	Low risk	Comment: no other sources of bias detected.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: Participants were aware of their allocation.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "assessors were kept unaware of the treatment condition".