Low rates of symptom exacerbation during and after massed cognitive processing therapy across veteran and community samples.

Clinicians have expressed concerns that symptoms may worsen during evidence-based treatments for posttraumatic stress disorder (PTSD), such as cognitive processing therapy (CPT). The current study examined rates of symptom exacerbation in two samples undergoing massed CPT: veterans (N = 499) and community members (N = 69). The Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5) was administered throughout treatment in both samples, and exacerbation was calculated based on changes from one assessment point to the next during treatment. Clinically reliable exacerbation, defined as a PCL-5 score increase greater than 8.83 points in consecutive measurements taken throughout treatment, was observed at least once in 27.3% of veterans and 21.7% of community members during treatment. Only 1.4% of veterans and 5.8% of community members reported reliably elevated symptoms from baseline at the end of treatment. The findings suggest low rates of clinically meaningful exacerbation during massed CPT, highlighting its utility across diverse populations and treatment formats. These results can inform clinician-patient discussions, alleviate concerns about worsening symptoms, and assuage clinician concerns about symptom exacerbation during CPT.