Program for Alleviating Relationship Trauma and Stress for Intimate Partner Violence - Randomized Control Trial

We previously tested a pilot program called PARTS-NB (Program For Alleviating Relationship Trauma and Stress- New Behaviors), an adaptation of the original PARTS Program and a study registered under the name of PARTS IPV (NCT06765122). The pilot program included unique and specific elements for People who Use Violence (PUV) in intimate relationships. Preliminary results from the PARTS IPV pilot suggest that intervention-based feasibility was met, with a total of 13 individuals attending at least 1 group and 12/13 individuals attending at least 8/12 of the first 12 groups. Mean acceptability was 26 (SD =3.4) meeting the acceptability criteria for the intervention at week 12. Moreover, individuals in the pilot PARTS IPV had overall declines in their aggression scales, minor psychological aggression (CTS2) and trended towards lower values and less variance in severe psychological aggression (CTS2). Interestingly, we also observed reductions in the frequency of individuals having six or more drinks (Question 3, AuditC).

Given these results, this project is an important and timely study with high-quality pilot randomized control clinical trial design. The methodology aligns closely with the specific aims described in this application and uses several innovative features and some carefully implemented gold-standard measures to ensure a high likelihood of success and publication. This will be the first RCT testing an intensive model of IFS group therapy designed specifically for those who use violence within intimate partner relationships with concurrent intermittent individual meetings for ongoing evaluation and support.

Previous reviews of interventions suggest there is a gap in effective interventions to treat IPV for those with trauma backgrounds (Cheng et al., 2021; Travers et al. 2021). PARTS1, PARTS2 and PARTS for Substance Use Disorder (PARTS SUD) have all demonstrated enhanced emotion regulation and self-related processing (Comeau et al. 2024; Ally et al. 2025; Joss et al. 2026). The protocol's methodology follows previous intimate partner violence studies, incorporating verbal consent and partner inclusion, while employing rigorously implemented informed consent procedures and gold-standard measures to enhance the likelihood of success and publication. While CBT IPV interventions vary in length (e.g., Strength at Home (SAH) groups are 12-weeks, standard state programs such as the psychoeducation program in the State of Washington are 26 sessions), we will use a phased approach that will run a total of 20 weeks with 20 group sessions and 6-9 individual sessions.

Primary Aims The primary aim of this study is to conduct a NIH Stage III hybrid "real-world implementation" study assessing the feasibility and acceptability (Nathan, 2007; Onken et al., 2014) of an Internal Family Systems intensive group program (Program for Alleviating and Reducing Trauma and Stress - IPV) (PARTS-IPV Phase 2) versus domestic violence treatment intervention treatment as usual (DVIT-TAU) control group on individuals mandated for treatment. We have two primary aims for this pilot RCT protocol: feasibility and acceptability.

Feasibility is defined in two ways: intervention-based feasibility: in both arms, we expect 70% of participants completing at least 67% (e.g., 8/12) of the first 12 groups. For study-protocol feasibility we do not expect differences in the arms but expect each arm to obtain overall 67% or more of participants completing week-20 study assessments (H1.1).

Secondary Aims H2.1: A secondary aim is overall acceptability of the intervention as measured by the Client Satisfaction Questionnaire (CSQ-8) (Larsen et al., 1979) where for both arms, we expect a mean score of at least 20 out of a total of 32 (H2.1).

H2.2: Intervention satisfaction, as measured by a satisfaction question (would you recommend a friend) will obtain at least a mean of 7 out of 10 (H2.2) in week 20 for both arms.

H2.3: Another secondary aim of the study is to investigate the potential effects of the intervention on the Revised Conflict Tactics Scale (CTS2) (Straus et al., 1996; Chapman \& Gillespie, 2019) and Multidimensional Measure of Emotional Abuse- Restrictive Engulfment (MMEA-RE Subscale) (Murphy \& Hoover, 1999). We hypothesize a risk reduction in physical and psychological violence from self-reports in both arms IFS/DVIT-TAU arm (H2.3). In our pilot (N=12), baseline mean of the psychological aggression subscale was 0.51 (SD=0.17), indicating that some participants had very high aggression scores while others did not. In Week 12, the mean was 0.13 (SD=0.12), suggesting that everyone clustered near zero, with a reduction in variability and suggesting a potential for stabilization in risk. Risk reduction in this case is both improvement and stabilization (decreased or stable scores).

For this pilot RCT, we hypothesize a greater risk reduction (decreased/stable scores) of psychological aggression use in the IFS arm compared to DVIT-TAU as measured by the psychological aggression subscale in CTS2 and MMEA-RE Subscale (H2.3).

H2.4: Lastly, in the pilot, we observed declines in the Aggression Experience Sampler (AES) from baseline to week 12. Average baseline scores were 13.97 (SE=0.63) with weekly rates of decline of -0.06 (p-value=0.09), indicating decreases ranging from 0.01 to 0.13 points per week. Based on these pilot findings we hypothesize that the 20-week RCT intervention will produce a weekly decline of -0.04 in AES scores (H2.4).

Exploratory Aims Exploratory outcomes include effects on mechanisms of emotion regulation, decentering, self-critical rumination, and self-compassion.

We hypothesize a greater capacity for decentering (Experiences Questionnaire - Decentering subscale (EQ)), reductions in self-critical rumination, reactivity in interpersonal relationships (OAS2, IRI-SF), as well as an increase in emotion identification and regulation (PAQ-S, Difficulties in Emotion Regulation Scale (DERS)), transcendent experiences (NADA-Bliss subscale), and self-compassion (using Self-Compassion Scale Short Form (SCS-SF)) self report, in IFS PARTS compared to DVIT-TAU at week 12 and 20. Other exploratory aims of the study are to investigate the effects of the intervention on general mental health including posttraumatic stress disorder, depression, anxiety (Achtyes et al., 2015; Guinart et al., 2021), and substance use (Craving Scale, AUDIT-C).

• H2.1. - Acceptability [Time frame: From enrollment to the end of treatment at 20 weeks]
• H2.2 -- Satisfaction [Time frame: From enrollment to the end of treatment at 20 weeks]
• H2.3 -- Conflict Tactics [Time frame: From enrollment to the end of treatment at 20 weeks]
• H2.4 -- Aggression Experience [Time frame: From enrollment to the end of treatment at 20 weeks]