Trauma exposure, posttraumatic stress disorder (PTSD), and substance use disorder (SUD) present major threats to public health. PTSD and SUD are major correlates of disability, often resulting in severe social and occupational impairment. Comorbidity between PTSD and SUD (PTSD/SUD) is common and frequently co-occurs with other mental health ailments including depression, anxiety, and suicidality. Comorbidity may be amplified in groups vulnerable to high trauma exposure, such as women with low socioeconomic status including women experiencing homelessness (WEH). Moreover, the reciprocal nature of PTSD/SUD (substances are used to cope with PTSD symptoms; substance use can create high-risk situations for new traumas to occur), can create a cycle of trauma and symptomatology leading to a critical health disparity.

PTSD/SUD can be costly and difficult to treat, with treatment completion often low and relapse rates often high. Low-cost, complementary interventions, such as self-compassion (SC) interventions, which target key mechanisms that maintain PTSD/SUD, could improve treatment outcomes. SC interventions include practices that build skills to improve emotional responses, cognitive understanding, and mindfulness. Recent research supports the benefit of SC interventions for reducing PTSD, SUD, and related comorbidities, potentially with large effects. However, sample sizes have generally been small and randomized designs infrequently used. Moreover, while SC interventions may act to improve key mechanisms of treatment response and/or symptom maintenance (e.g., emotion regulation/dysregulation, trauma-related guilt, trauma-related shame, moral injury, and craving), such mediating factors have been underexplored. To address these limitations, the present proposal will implement community-based research principles and use a two phase, mixed-method design to adapt and test a widely used SC intervention (Mindful Self Compassion; MSC) for use with a sample of WEH with PTSD/SUD. The project will be conducted in partnership with a state-funded drug treatment facility that serves women and families experiencing high health disparities.

Phase I was completed in 2023 and adapted the standard MSC course for use with trauma-exposed WEH with PTSD/SUD using the ADAPT-ITT model, an eight-stage model that engages community partners to increase feasibility and acceptability of interventions for at-risk populations.

Phase II will be an open-label cluster randomized clinical trial (N=202) to test the benefit of the adapted MSC at improving primary (PTSD, substance use) and secondary outcomes (depression, anxiety, hopelessness) among a sample of WEH with PTSD/SUD residing in a residential drug treatment site. MSC (n=101) will be compared to Treatment as Usual (TAU; n=101). WEH in the MSC group will complete a 6-week (six sessions plus a half-day retreat) MSC intervention.

The TAU group will engage in weekly check-ins with the research team but will not receive an intervention. WEH will be assessed at baseline, immediately post-intervention, and at a 4-month follow-up. One-on-one interviews will be conducted with the MSC group to collect qualitative data on experiences. An exploratory aim will be to elucidate mechanism of treatment-response and maintenance or remission of PTSD symptoms. These potential mechanisms will include SC, emotion regulation/dysregulation, trauma-related guilt, trauma-related shame, moral injury, and craving.

Results may inform treatment for PTSD/SUD in WEH and other groups experiencing high health disparities and provide valuable insights into mechanisms underlying PTSD/SUD symptoms over time. Findings are relevant to military populations, which experience high rates of PTSD/SUD, and other populations disproportionately exposed to trauma.

Inclusion Criteria:

• Identifies as woman
• Age 18 and over
• Probable PTSD as judged by the PCL-5 (score of 31 or higher, indicated as having optimal signal detection)
• No cognitive impairment according to a score of < 10 on the Short-Blessed Test
• Experienced homelessness in the past 6 months or prior to incarceration ("spent night in public or private shelter or on the street")
• Able to speak and understand English.

Exclusion Criteria:

• Not able to speak English
• Judged to be cognitively impaired, as indicated by score > 10 on the Short-Blessed Screener
• Does not meet other inclusion criteria

Biological women or individuals who identify as a woman are eligible to participate in the study

Deidentified, quantitative data will be shared along with a codebook and data dictionary. Data will be completely deidentified.