BACKGROUND:Post-traumatic stress disorder (PTSD) refers to an anxiety or trauma- and stressor-related disorder that is linked to personal or vicarious exposure to traumatic events. PTSD is associated with a range of adverse individual outcomes (e.g. poor health, suicidality) and significant interpersonal problems which include difficulties in intimate and family relationships. A range of couple- and family-based treatments have been suggested as appropriate interventions for families impacted by PTSD. OBJECTIVES:The objectives of this review were to: (1) assess the effects of couple and family therapies for adult PTSD, relative to 'no treatment' conditions, 'standard care', and structured or non-specific individual or group psychological therapies; (2) examine the clinical characteristics of studies that influence the relative effects of these therapies; and (3) critically evaluate methodological characteristics of studies that may bias the research findings. SEARCH METHODS:We searched MEDLINE (1950- ), Embase (1980- ) and PsycINFO (1967- ) via the Cochrane Common Mental Disorders Controlled Trials Register (CCMDCTR) to 2014, then directly via Ovid after this date. We also searched the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Library. We conducted supplementary searches of PTSDPubs (all available years) (this database is formerly known as PILOTS (Published International Literature on Traumatic Stress)). We manually searched the early editions of key journals and screened the reference lists and bibliographies of included studies to identify other relevant research. We also contacted the authors of included trials for unpublished information. Studies have been incorporated from searches to 3 March 2018. SELECTION CRITERIA:Eligible studies were randomised controlled trials (RCTs) of couple or family therapies for PTSD in adult samples. The review considered any type of therapy that was intended to treat intact couples or families where at least one adult family member met criteria for PTSD. It was required that participants were diagnosed with PTSD according to recognised classification systems. DATA COLLECTION AND ANALYSIS:We used the standard methodological procedures prescribed by Cochrane. Three review authors screened all titles and abstracts and two authors independently extracted data from each study deemed eligible and assessed the risk of bias for each study. We used odds ratios (OR) to summarise the effects of interventions for dichotomous outcomes, and standardised mean differences (SMD) to summarise post-treatment between-group differences on continuous measures. MAIN RESULTS:We included four trials in the review. Two studies examined the effects of cognitive behavioural conjoint/couple's therapy (CBCT) relative to a wait list control condition, although one of these studies only reported outcomes in relation to relationship satisfaction. One study examined the effects of structural approach therapy (SAT) relative to a PTSD family education (PFE) programme; and one examined the effects of adjunct behavioural family therapy (BFT) but failed to report any outcome variables in sufficient detail - we did not include it in the meta-analysis. One trial with 40 couples (80 participants) showed that CBCT was more effective than wait list control in reducing PTSD severity (SMD -1.12, 95% CI -1.79 to -0.45; low-quality evidence), anxiety (SMD -0.93, 95% CI -1.58 to -0.27; very low-quality evidence) and depression (SMD -0.66, 95% CI -1.30 to -0.02; very low-quality evidence) at post-treatment for the primary patient with PTSD. Data from two studies indicated that treatment and control groups did not differ significantly according to relationship satisfaction (SMD 1.07, 95% CI -0.17 to 2.31; very low-quality evidence); and one study showed no significant differences regarding depression (SMD 0.28, 95% CI -0.35 to 0.90; very low-quality evidence) or anxiety symptoms (SMD 0.15, 95% CI -0.47 to 0.77; very low-quality evidence) for the partner of the patient with PTSD. One trial with 57 couples (114 participants) showed that SAT was more effective than PFE in reducing PTSD severity for the primary patient (SMD -1.32, 95% CI -1.90 to -0.74; low-quality evidence) at post-treatment. There was no evidence of differences on the other outcomes, including relationship satisfaction (SMD 0.01, 95% CI -0.51 to 0.53; very low-quality evidence), depression (SMD 0.21, 95% CI -0.31 to 0.73; very low-quality evidence) and anxiety (SMD -0.16, 95% CI -0.68 to 0.36; very low-quality evidence) for intimate partners; and depression (SMD -0.28, 95% CI -0.81 to 0.24; very low-quality evidence) or anxiety (SMD -0.34, 95% CI -0.87 to 0.18; very low-quality evidence) for the primary patient. Two studies reported on adverse events and dropout rates, and no significant differences between groups were observed. Two studies were classified as having a 'low' or 'unclear' risk of bias in most domains, except for performance bias that was rated 'high'. Two studies had significant amounts of missing information resulting in 'unclear' risk of bias. There were too few studies available to conduct subgroup analyses. AUTHORS' CONCLUSIONS:There are few trials of couple-based therapies for PTSD and evidence is insufficient to determine whether these offer substantive benefits when delivered alone or in addition to psychological interventions. Preliminary RCTs suggest, however, that couple-based therapies for PTSD may be potentially beneficial for reducing PTSD symptoms, and there is a need for additional trials of both adjunctive and stand-alone interventions with couples or families which target reduced PTSD symptoms, mental health problems of family members and dyadic measures of relationship quality.