Posttraumatic stress disorder (PTSD) is associated with significant disability and can become chronic. Predictors of PTSD symptom changes over time, especially in those with a PTSD diagnosis, remain incompletely characterized. In the present study, we examined 187 post-9/11 veterans (M age= 32.8 years, 87% male) diagnosed with PTSD who performed two extensive clinical and cognitive evaluations approximately 2 years apart. We found that greater PTSD symptom reductions over time were related to lower lifetime drinking history and better baseline inhibitory control ability (Color-Word Inhibition and Inhibition/Switching), though not performance on other executive function tasks. Further, groups with reliably Improved, Worsened, or Chronic PTSD symptoms demonstrated significant differences in baseline inhibitory control and lifetime drinking history, with marked drinking differences starting in the early-to-mid 20s. We also found that PTSD symptom changes showed little-to-no associations with changes in inhibitory control or alcohol consumption. Together, these findings suggest that, in those diagnosed with PTSD, inhibitory control and alcohol use history reflect relatively stable risk/resiliency factors predictive of PTSD chronicity.(PsycInfo Database Record (c) 2023 APA, all rights reserved)