Massed Prolonged Exposure for PTSD in Substance Use Treatment
The goal of this clinical trial is to learn if receiving Prolonged Exposure Therapy for PTSD in massed format (multiple sessions weekly) is as effective as receiving it with sessions once per week among veterans with PTSD and substance use disorder in intensive outpatient substance use treatment. The main questions it aims to answer are:

Will the massed format help participants complete and benefit from Prolonged Exposure in terms of PTSD symptoms?
Will it help participants reduce substance use? Participants who are in intensive substance use treatment will be asked to complete Prolonged Exposure with either weekly sessions or multiple sessions per week.
- EligibilityCriteria: Inclusion Criteria:  Veterans age 18+ who have served since September 2001 who are enrolled in a SUD IOP at a participating VA meet DSM-5 criteria for a current SUD (Tobacco Use Disorder alone not sufficient for inclusion) meet DSM-5 criteria for PTSD report substance use at least 20 of the last 90 days are able to give informed consent.  Exclusion Criteria:  severe cognitive impairment current suicidal or homicidal intent requiring immediate treatment current unstable psychotic or manic symptoms not attributable to SUD - HealthyVolunteers: No - Gender: All - GenderBased: Yes - MinimumAge: 18 Years - StdAgeList: Adult, Older Adult