This single-arm study will test the preliminary efficacy of a virtually delivered, live-online 12-week group model of Internal Family Systems (IFS) for individuals with posttraumatic stress disorder (PTSD) and substance use disorders (Program for Alleviating and Reducing Trauma, Stress, and Substance Use, PARTS-SUD).

Participants will be in a group for 12 weeks and will be asked to complete survey sessions at baseline and during week 4, 8 and 12.

The investigators have conducted a single arm study of a 16 week PARTS group-based program for PTSD symptoms, which demonstrated large effect reductions on PTSD symptoms, disturbances in self-organization (DSO), disassociation, emotion dysregulation, suicide risk, anxiety, depression, and increases in decentering and self-compassion. A randomized control trial (RCT) of PARTS groups vs. a control is currently underway and will complete by September 2023. This will be a single-arm feasibility and acceptability pilot study of PARTS for PTSD among patients with substance use disorders.

While 16 weeks is the typical length for PTSD intervention trials, the average treatment length for PTSD-SUD population studies is only 12 weeks given higher risk of attrition with longer treatments for substance use disorder (SUD). Clinically, the group is anticipated to have the most impact on symptoms between weeks and 12 based on the curriculum and practices during those sessions, so the investigators will pilot a 12 week group in this study. Similar to past PARTS studies, participants will also have every other week 50 minute individual counseling sessions. Since IFS and group psychotherapy are established modalities and the pilot trial for PARTS established its evidence as a program with a clinically meaningful effect, this feasibility and acceptability study will primarily focus on the engagement and acceptability of the intervention among patients with PTSD-SUD. Both group and individual sessions will be billed to insurance as per standard Cambridge Health Alliance (CHA) outpatient clinical protocols. To reduce burden from past studies, the investigators will not conduct Clinician-Administered PTSD Scale (CAPS-5) interviews, but solely use self-report measures (PTSD Checklist For DSM-5, PCL-5 and Computerized Adaptive Testing for PTSD, CAT-PTSD), which have a high level of correlation with CAPS-5.

The investigators aim to have 10-12 participants allocated to start the program aiming for 70% of completion of the study intervention (defined as 75% completion of sessions) and 70% completion of week 12 assessments with adequate intervention acceptability. After participants have completed all baseline screenings, assessments and the informed consent procedure, a study staff member will contact them to begin the virtual program delivered in real time over the secure, HIPAA compliant video conference (e.g. Google Meets, Zoom).

Surveys, Procedures and Duration The duration of the study period is 12 weeks (see Figure 1). Participants will complete screening surveys and a long survey battery at baseline; survey batteries (approximately 62 minutes) at study Week 4, 8 and 12; and weekly substance use and craving self-report assessments.

All study procedures (screening, consent and assessments) can be conducted virtually, by videoconference and online through the secure REDCap survey database. These procedures may also be conducted in-person at a CHA community mental health center, and/or at the Center for Mindfulness and Compassion (CMC, 350 Commerce Place, Malden, MA).

Inclusion Criteria:

• Able to bill insurance for group psychotherapy and individual psychotherapy at CHA;
• Currently or willing to become a patient of CHA primary care or behavioral health care (as defined by an active CHA EPIC EHR record);
• Have a current diagnosis of PTSD OR a CAT-MH PTSD>58;
• Have a current diagnosis of a substance use disorder (SUD), positive Alcohol Use Disorders Identification Test AUDIT-C item about 5 or more drinks at once OR positive toxicology for or self-report of illicit drugs in the past year, or current treatment with medications for OUD, including buprenorphine, naltrexone or methadone.
• Have sufficient English fluency and literacy skills to understand the consent process, procedures and questionnaires and have the ability to provide written informed consent;
• Have access to the internet and an electronic device with adequate data capacity; to complete questionnaires online and attend online video conference groups;
• Must be available and willing to attend 10 of 12 scheduled online group sessions for 12 weeks; and
• Must be available and willing to complete the online computerized assessments and phone interviews.

Exclusion Criteria:

• Inability to complete an informed consent assessment AND/OR inability to complete baseline study assessment procedures (due to cognitive deficit, non-proficiency in English literacy, or for any other reason);
• Current participation in another experimental research study;
• Expected medical hospitalization in the next four months from enrollment period;
• Expected incarceration in the next four months from enrollment period;
• Individuals who are pregnant with a due date within 16 weeks after study consent;
• Insufficient level of severity of PTSD symptoms: PTSD score of less than 33 on the PTSD Checklist for DSM-V (PCL-5) at screening visit will require clinical review to consider eligibility;
• Insufficiently stable housing or internet connection to join at least 10 sessions;
• Inability to participate safely in the study intervention and without disrupting the group (in the opinion of principal investigator OR meeting any of the following criteria):
• Past year history of a psychotic disorder or clinician confirmed active psychosis (Severe level of psychosis on PSY-S-CAT > 60 will require clinical assessment prior to participation in the program)
• Bipolar I disorder history or current severe level of mania on CAT-M/H (>70) will require of a clinical assessment prior to participation in the program
• Acute suicidality with intent will be excluded from the study (Columbia Suicide Rating Scale items 4-6 positive);
• Self-injurious behavior in past three months will require clinical assessment prior to participation in the program;
• Acute homicidality with plan and/or intent;
• Inpatient hospitalization for mental health, substance use, suicide attempt or self-harm within past three months;
• Severe Borderline Personality Disorder or other severe personality disorder with clinical history that would suggest potential disruptions within the group (would require clinical review);
• Inability to join a group without intoxication; and/or
• History of charges for perpetrating intimate partner violence will require clinical assessment prior to participation in the program.