Phase-based psychological interventions for complex post-traumatic stress disorder: A systematic review

Debate is ongoing as to whether phase-based or single-phase interventions should be recommended for Complex Post-Traumatic Stress Disorder (CPTSD). This is a systematic review of the evidence for phase-based interventions for CPTSD, the impact of Phase 1 interventions on outcomes in later phases, and the efficacy of phase-based interventions for adults and children and young people (CYP) with CPTSD. Eligible studies included participants diagnosed with CPTSD, PTSD and interpersonal trauma exposure before the age of 18, or PTSD with self-described symptoms of CPTSD. Twelve studies were included in the review, with four focused on children and young people. Phase-based treatments are effective, in some cases, significantly more so than single-phase therapies. Effect sizes ranged from d=0.02-1.6 (adults) and d=0.9-2.39 (CYP) for studies with a passive control, and d=0.12-1.29 (adults) and d=0.21-0.7 (CYP) for studies with active controls. The impact of Phase 1 on Phase 2 outcomes was mixed with only one study finding significant benefit. The two phases may impact different outcomes. Phase-based treatments, particularly Trauma-Focused Cognitive Behavior Therapy (TF-CBT), were effective for CYP. Those who might benefit most from Phase 1 interventions were typically excluded, reducing ecological validity. Failure to use diagnostic criteria in youth samples meant few studies were eligible for inclusion, and inconsistency in control groups impinged on comparability. Inclusion criteria should be improved in future studies to achieve ecological validity, especially in studies with youth.