How changes in post‐traumatic stress disorder (PTSD) severity mediate substance use disorder (SUD) severity during and after treatment for co‐occurring PTSD and SUD: Results from Project Harmony. - Hien, Denise A.; Gette, Jordan A.; Blakey, Shannon M.; Piccirillo, Marilyn L.; Back, Sudie E.; Bauer, Alexandria G.; Ebrahimi, Chantel T.; Ellis, Robyn A.; Killeen, Therese K.; Lehinger, Elizabeth A.; López‐Castro, Teresa; Norman, Sonya B.; et al. (Addiction, 2025)