Research Evidence - Foundation for Self Leadership
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Overview

Since its founding, the Foundation for Self Leadership has aimed to catalyze, not direct or control, independent research on Internal Family Systems (IFS) therapy. The therapy modality, developed by Richard C. Schwartz in the mid-eighties, has gained momentum and mounted experiential evidence in the clinical space. To help examine its efficacy as a psychotherapeutic treatment, our role has been to seed independent, investigator-led studies that subject IFS to the same scientific scrutiny applied to other psychotherapeutic approaches, and to curate the growing evidence base for the wider community.

To preserve scientific integrity, the Foundation operates at arm's length from the research itself. Independent academic and clinical teams design the studies, secure ethical approvals, recruit participants, deliver interventions, analyze data, and publish results in peer-reviewed journals. The Foundation provides funding, connection, and visibility, while deliberately deferring to the rigors of science in study design, analysis, and interpretation.

Over the past decade, private charitable contributions have enabled the Foundation to support four studies, leading to at least three peer-reviewed journal articles to date (November 2025) with a few more in the hopper, and a new research fellowship program. Here is a sample:

  • A series of clinical outcome studies evaluating IFS for complex PTSD, co-occurring PTSD and substance-use disorders, and related conditions.
  • Among those, a sizable, multi-year randomized clinical trial (RCT) of IFS as a treatment for PTSD, accompanied by a feasibility study on IFS and opioid use, both conducted at a Harvard-affiliated community mental health center.
  • The Richard C. Schwartz Research Fellowship, which supports emerging clinical scientists dedicated to examining IFS through rigorous research and embeds IFS-focused inquiry in leading academic centers. Two Fellows have been supported by the Foundation: Dilara Ally, PhD, LCSW (Inaugural Fellow) and Diane Joss, PhD.

In parallel, the Foundation has cultivated a community of researchers, created and maintains an annotated IFS publications database for researchers and practitioners, helping the field track and synthesize the expanding literature on IFS across clinical, community, and organizational settings. Additionally, adherence scales and IFS scales are among resources being shared through this website; the Foundation is constantly looking for researchers to help to update and refine these scales.

Today, IFS is a practice with an emerging base of empirical evidence. It is expected that these efforts will inspire and generate external funding for further studies, contributing to a steadily expanding empirical foundation for IFS as a psychotherapeutic modality—across conditions, populations, and cultural contexts—while keeping research independent, transparent, and replicable.

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Funded Studies

Summaries of four Foundation-funded studies are presented below. They have all been conducted by independent research teams and published (or in press) in peer-reviewed journals.

Another Foundation-Funded Study Published: Randomized Controlled Trial on the Effects of the IFS-Focused Program for Alleviating and Resolving Trauma and Stress (PARTS)

Study type: Randomized Controlled Trial (completed; published in Psychological Trauma: Therapy, Research, Practice, and Policy (2026) as "A randomized controlled trial of an online group-based internal family systems treatment for posttraumatic stress disorder: The Program for Alleviating and Resolving Trauma and Stress (PARTS) study")

Principal investigator: Zev Schuman-Olivier, MD; Center for Mindfulness and Compassion, Cambridge Health Alliance

  • This is a Foundation-funded pilot RCT of a 16-week group-based PTSD treatment program derived from the IFS theoretical framework.
  • The study randomized 60 patients either to the PARTS intervention or an active control arm (Nature-Based Stress Reduction for Trauma Survivors), with 30 patients in each treatment arm.
  • PTSD symptoms were measured using the gold standard clinician-administered CAPS-5 (Clinician-Administered PTSD Scale) assessment.
  • Both treatment arms showed statistically significant large reductions in PTSD symptoms (p < .001); e.g. (stress and trauma) the PARTS arm showed a mean CAPS-5 score reduction of −11.0 (Cohen's d = −1.4) and the Nature-Based Stress Reduction for Trauma Survivors arm showed a mean reduction of −13.2 (Cohen's d = −1.7), with no statistically significant difference between the two arms. These large effect size reductions were similar in magnitude to other active, evidence-based treatments for PTSD such as cognitive processing therapy, cognitive behavioral therapy, prolonged exposure, and eye-movement desensitization and reprocessing.
  • The PARTS arm had significantly better group attendance (12.8 out of 16 sessions vs. an average of 10) and higher levels of group satisfaction than the control arm. Read More.

PARTS-SUD (Program for Alleviating and Reducing Trauma, Stress, and Substance Use): IFS for Co-Occurring PTSD and Substance Use Disorders

Study type: Feasibility Study (completed; published in Frontiers in Psychiatry (2025) as "A pilot study of an online group-based Internal Family Systems intervention for co-occurring PTSD and substance use disorders")

Principal investigator: Zev Schuman-Olivier, MD; Center for Mindfulness and Compassion, Cambridge Health Alliance

  • This is a Foundation-funded pilot of an online IFS-based intervention for adults with both PTSD and substance use disorders (SUD).
  • The IFS treatment was delivered via 12 weekly group sessions plus 6 individual IFS counseling sessions, targeting both trauma and substance use.
  • The study exceeded pre-specified feasibility and acceptability targets; participants reported high satisfaction and retention, with promising improvements in PTSD symptoms and substance-use outcomes. Read More.

Program for Alleviating and Resolving Trauma and Stress (PARTS): Online Group-Based IFS Treatment for PTSD

Study type: Feasibility / proof-of-concept clinical trial (completed; published in Psychological Trauma: Theory, Research, Practice, and Policy (2024) under the title "Online group-based internal family systems treatment for posttraumatic stress disorder: Feasibility and acceptability of the program for alleviating and resolving trauma and stress (PARTS)")

Principal Investigator: Zev Schuman-Olivier, MD; Center for Mindfulness and Compassion, Cambridge Health Alliance, Harvard Medical School affiliate

  • This Foundation-funded study took place during COVID, running largely online. It examined a 16-week hybrid IFS-based intervention combining online group sessions with individual IFS counseling for adults with PTSD in a diverse, community-based health system.
  • It demonstrated feasibility and acceptability of delivering IFS in an online group format within community mental health, with significant reductions in PTSD symptom severity by week 16. Read More.

IFS Therapy for PTSD and Complex Childhood Trauma

Study Type: Uncontrolled feasibility pilot (completed; published in the Journal of Aggression, Maltreatment & Trauma (2021) as "Internal Family Systems (IFS) Therapy for Posttraumatic Stress Disorder (PTSD) among Survivors of Multiple Childhood Trauma: A Pilot Effectiveness Study")

Principal Investigator: Hilary Hodgdon, PhD: Trauma Center at Justice Resource Institute, Brookline, MA

  • This is the first Foundation-funded independent IFS study (grant awarded in 2014).
  • The study involved 17 adults with PTSD and histories of multiple forms of childhood trauma received 16 weekly 90-minute IFS sessions.
  • Results showed significant reductions in PTSD and depressive symptoms, as well as improvements in affect regulation, somatization, dissociation, self-compassion, and interoceptive awareness; at one-month follow-up, 92% no longer met criteria for PTSD. Read More.
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Other Studies

The Foundation's efforts fit within a broader body of IFS research conducted by independent investigators worldwide, including trials and studies not funded by the Foundation. Here is a sample of such research papers published and recognition for IFS as a modality with an emerging base of empirical evidence.

Two Randomized Controlled Trials (RCTs)

  • Rheumatoid Arthritis Study: A randomized controlled trial of an IFS-based intervention for rheumatoid arthritis (RA), with a sizable sample conducted as a proof-of-concept study, published in the Journal of Rheumatology (2013). Read More.
  • Depression in Female College Students: A study examining IFS for depressed female college students that found subjects randomized to IFS experiencing (n=17) beneficial changes relative to treatment-as-usual controls (n=15), indicating that IFS (16 sessions) may offer an effective alternative for young adults who do not fully benefit from existing evidence-based treatments. This was published in the Journal of Marital and Family Therapy by Haddock et al. 2016.

Evidence emerging from the above 2013 published RCT study contributed to the recognition of IFS as an evidence-based practice by SAMHSA's former National Registry of Evidence-based Programs and Practices (NREPP) in 2015. While this database is no longer active, the full recognition of IFS as it appeared then can be found verbatim across these pages.

NREPP's independent review rated IFS "effective" for improving general functioning and well-being, and "promising" for depression, anxiety, physical health conditions, and personal resilience/self-concept.

NREPP Posting

NREPP accepted and recognized IFS Therapy as a modality with emerging empirical evidence

In the second half of 2014 and following an independent, rigorous review, the National Registry of Evidence-based Practices and Programs (NREPP), accepted for review a comprehensive application by the Foundation for Self Leadership, prepared on behalf of The Center for Self Leadership and the community. The application was a formal request to consider IFS Therapy as an evidence-based psychotherapeutic modality. The application had been submitted in early 2014 and was included in a new cohort of applicants subject to some new NREPP guidelines for review.

NREPP, which was an entity operating within the U.S. Substance Abuse and Mental Health Services Administration (SAMHSA), had engaged private researchers to review all submissions independently and conduct a two-tier rigorous evaluation, examining the quality of the research about IFS, which had to be based on a randomized clinical trial (RCT), and the capacity to disseminate the named modality.

The application revolved around a proof-of-concept RCT study, completed and published in a peer-review research journal, by Nancy Shadick, MD, MPH; Nancy Sowell, MSW, LICSW; and collaborators. The full article is available here.

In late 2015, the Foundation was notified that NREPP accepted and recognized IFS Therapy as an evidence-based modality. This simply represented an independent nod to a status of emerging empirical evidence, suggesting many more studies were needed to assess the modality's effectiveness in treating various conditions. See statement announcing it.

As a clinical treatment, it was independently confirmed that, based on the aforementioned RCT study, IFS Therapy reportedly produced five outcomes, one considered effective and four promising. The paper outcomes covered areas of efficacy that appeared to deal with positive effects on body, mind, and spirit—among them: improving general functioning and well-being, reducing depression and depressive symptoms, and improving resilience and self-concept.

Through the following link, the full posting of the SAMHSA-NREPP is presented verbatim as it had appeared on NREPP.SAMHSA.Gov.