Experimental: MDMA-assisted Cognitive Processing Therapy (MDMA-aCPT)

This arm consists of 8-15 virtual CPT sessions (average of 12), one 90-minute, non-drug Preparatory Session, three Experimental Sessions with MDMA (\~8 hours), and three 90-minute, non-drug Integration Sessions, occurring over a 9-15-week Treatment Period. Standardized homework is assigned at each CPT session to promote the practice of the skills taught in the session. Participants will receive 80mg MDMA HCl for the first Experimental Session and will have the option of a supplemental dose of 40mg MDMA HCI 1.5-2 hours after the initial dose. For the second and third Experimental Sessions, participants will receive either 80mg or 120mg MDMA HCl as the initial dose, and an optional supplemental dose of 40mg or 60mg MDMA HCl 1.5-2 hours after the initial dose. Participants interested in receiving CPT treatment alone after study completion will have the option to be referred to their local VA PTSD Clinical Team for services 6 months after all study visits are completed.

Experimental: Cognitive processing therapy

This arm consists of 8-15 virtual CPT treatment sessions lasting approximately 1-1.5 hours, occurring over a \~12-16-week Treatment Period. These sessions will take place approximately one week apart. Standardized homework is assigned at each session to promote the practice of the skills taught in the session. Participants will have the option to crossover to the MDMA-aCPT arm 6 months after all study visits are completed.