Veterans' 12-month PTSD and depression outcomes following 2- and 3-week intensive cognitive processing therapy-based treatment.

Background: Growing evidence indicates that daily delivery of evidence-based PTSD treatments (e.g. Cognitive Processing Therapy (CPT)), as part of intensive PTSD treatment programmes (ITPs), is feasible and effective. Research has demonstrated that a 2-week CPT-based ITP can produce equivalent outcomes to a 3-week ITP, suggesting shorter treatment can also be highly effective. However, the extent to which ITP length and composition impact longer-term outcomes needs further study. Objective: We examined whether PTSD and depression symptoms 3-, 6-, and 12-months following completion of a 2-week ITP could be considered non-inferior, or equivalent, to those of a 3-week ITP. Method: Data from 638 veterans who participated in a 2-week CPT-based ITP were evaluated against 496 veterans who participated in a 3-week CPT-based ITP. A Bayes factor approach was used to examine whether PTSD and depression severity outcomes of the 2-week ITP could be considered equivalent to the 3-week ITP. Results: Participants across both ITPs reported large PTSD ( d  = 0.98) and moderate to large depression symptom reductions ( d  = 0.69) from baseline to 12-month follow-up. The PTSD and depression symptom reductions seen in the 2-week ITP were determined to be equivalent to those of the 3-week ITP. Conclusions: Low follow-up completion was a limitation. Future research might replicate the present findings using samples with greater follow-up rates and explore whether adjunctive services impact other relevant constructs, such as quality of life and functioning.