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State of the ACT Evidence

The CBS tradition is committed to a high standard of empirical evaluation. This includes not just controlled assessment and evaluations of outcomes but also the specification and evaluation moderations and of the putative processes of change. Furthermore, we also seek to understand the links between these processes of change and basic functional behavioral and evolutionary science principles, including those drawn from RFT. As the best known applied wing of CBS, all of these features are important to ACT research.

One web page is unable to collect together the growing evidence for all of the above areas at one time point or to keep it up to date going forward. More modestly, the three sections below aim to provide information on:

1. Organizations that describe ACT, or areas of ACT, as evidence based
2. Links to peer reviewed assessments of the ACT evidence base including evidence on processes of change
3. Links to various summaries of particular kinds of research

This page is normally updated every month. If you are aware of missing data, please contact the ACBS staff: [email protected].

The date of last update: March 2026

1. Organizations that describe ACT, or areas of ACT, as evidence based:

A number of different organizations, external to ACBS, have stated that ACT is empirically supported in certain areas or as a whole according to their standards. These include:

i. World Health Organization

  • Pain (Children and Adolescents) - WHO lists ACT as empirically supported ("moderate certainty") in the reduction of functional disability in children and adolescents with chronic pain (click here for the report).
  • WHO recommends ACT for Generalized anxiety disorder (click here for the fact sheet).
  • WHO recommends ACT as a care pathway to manage depressive symptoms in older people and to support carers of older people (click here for the handbook)
  • Self-Help Plus (SH+) is WHO’s stress management course based on ACT for large groups of up to 30 people. SH+ uses pre-recorded audio and an illustrated guide (Doing What Matters in Times of Stress). Randomized controlled trials have been shown to reduce psychological distress and prevent the onset of mental disorders. Self-Help Plus (SH+) is available in 13 languages. Doing What Matters in Times of Stress is a stress management illustrated guide for coping with adversity. The WHO website states "Informed by evidence and extensive field testing, the guide is for anyone who experiences stress, wherever they live and whatever their circumstances." Doing What Matters in Times of Stress: Illustrated Guide is available in 45 languages.
     

UNITED STATES

ii. American Psychological Association, Society of Clinical Psychology (Div. 12), Research Supported Psychological Treatments:

iii. U.S. Dept of Veterans Affairs / U.S. Dept of Defense

iv. U.S. Department of Health and Human Services, Administration for Children and Families, Title IV-E Prevention Services Clearinghouse (click here for the report).

  • Mental Health Programs and Services: Well Supported
  • Substance Abuse Programs and Services: Well Supported
     

v. U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration (SAMHSA)

vi. US Department of Justice, Office of Justice Programs

  • ACT for Partner Aggression: Evidence Rating: Effective (click here for the report)
     

vii. California Evidence-Based Clearinghouse for Child Welfare

  • Depression Treatment (Adult) - Scientific Rating 1 (Well Supported by Research Evidence) (click here for the report)
     

viii. Washington State Institute for Public Policy - WSIPP systematically assesses all high-quality studies from the United States and elsewhere to identify evidence based policy options that have been tested and found to achieve improvements in outcomes.

ix. American Headache Society

AUSTRALIA

x. Australian Psychological Society, Evidence Based Psychological Interventions (2024):

  • Bipolar disorder (group) - Level I Evidence
  • Depression – Level I Evidence
  • Obsessive compulsive disorder – Level I Evidence
  • Psychotic disorders – Level I Evidence
  • Substance use disorders – Level I Evidence
  • Anxiety disorders - Generalised anxiety disorder – Level II Evidence
  • Anxiety disorders - Social anxiety disorder – Level II Evidence
  • Anxiety disorders - Panic disorder – Level II Evidence
  • Borderline personality disorder (group) – Level II Evidence
  • Hypochondriasis – Level II Evidence
  • Insomnia disorders (group) - Level II Evidence
  • Binge eating disorder – Level IV Evidence
  • Body dysmorphic disorder – Level IV Evidence
  • Functional neurological symptom disorder - Level IV Evidence
     

Australian Psychological Society, 2018 Evidence Based Psychological Interventions in the Treatment of Mental Disorders:

  • Adults: Pain Disorders – Level II Evidence
  • Children (age 10-14 years): Pain Disorders – Level II Evidence
     

BANGLADESH 

xi. Bangladesh Association of Psychiatrists (BAP), Guidelines for the Management of Obsessive-Compulsive Disorder (2022)

  • Recommends ACT as a psychological treatment for OCD
     

CANADA

xii. Canadian Coalition for Seniors’ Mental Health (CCSMH), Canadian Guidelines for the Assessment and Treatment of Anxiety in Older Adults (2024)

  • Recommendation: ACT may be offered to older adults with anxiety.
     

xiii. Canadian Network for Mood and Anxiety Treatments (CANMAT)

GERMANY

xiv. German Society for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy (DGKJP) and German Association for Psychiatry and Psychotherapy, Psychosomatics and Neurology (DGPPN), Guideline on Autism Spectrum Disorders in Childhood, Adolescence, and Adulthood (2021)

  • Recommends Autism-specific psychosocial therapy with elements of ACT for school-aged children and adolescents without intellectual disability. Level of Evidence: 1-2
  • Recommends Autism-specific psychosocial therapy with elements of ACT for adults without intellectual disability. Level of Evidence: 2
  • Older adolescents and adults can be offered elements of ACT with an autism-specific adaptation for the treatment of anxiety disorders. Level of Evidence: 3
     

xv. German Association for Psychiatry and Psychotherapy, Psychosomatics and Neurology (DGPPN)

xvi. German Society of Otorhinolaryngology, Head and Neck Surgery, Chronic Tinnitus Guideline (2021)

  • Behavioral therapy, including ACT, should be recommended for chronic tinnitus. Strength of evidence: high Strength of recommendation: strong
     

xvii. German Pain Society, the German Society for Geriatrics (DGG), and Independent Association of Active Pain Patients in Germany (UVSD SchmerzLOS), Guideline on Pain Management in Geriatric Patients Across All Care Settings (GeriPAIN) (2025)

  • Mindfulness-based interventions (including ACT) should be implemented in geriatric patients with chronic pain to improve pain-related functioning and mental well-being. Level of Evidence: 2
     

xviii. German Society of Gastroenterology, Digestive and Metabolic Diseases (DGVS), Guideline on the “Diagnosis and Therapy of Crohn’s Disease” (2024)

  • Acceptance and Commitment Therapies may be offered for stress reduction. Level of evidence: 1
     

xix. German Society for Addiction Medicine (DGS) and German Society for Addiction Research and Addiction Therapy (DG-Sucht), Opioid-Related Disorders Guideline (2025)

  • Recommends offering ACT to individuals with opioid-related disorders undergoing therapy. Recommendation Level: B
     

KOREA

xx. The Society of Korean Medicine Neuropsychiatry, Korean Medicine Clinical Practice Guideline for Hwabyung (2021).

  • The Korean Medicine Clinical Practice Guideline for Hwabyung recommends ACT with a Strength of Recommendation - Level A. The guideline states ACT has Level of Evidence - Moderate.
     

NETHERLANDS

xxi. Netherlands Institute of Psychologists: Sections of Neuropsychology and Rehabilitation, Richtlijn Neuropsychologie Revalidate (2017)

  • The Netherlands Institute of Psychologists (NIP) recommends ACT for patients with MS with depressive symptoms.
     

SPAIN

xxii. The Spanish Society of Neurorehabilitation, Principios básicos del manejo del dolor en el daño cerebral sobrevenido. Recomendaciones de la Sociedad Española de Neurorrehabilitación (2021).

  • Recommends ACT for the management of pain. Grade of Recommendation - Level A.
     

SWEDEN

xxiii. Sweden Association of Physiotherapists, Fysioterapi Profession och vetenskap (2016)

  • The Swedish Association of Physiotherapy (physical therapy) includes ACT as a physiotherapeutic theory and practice in the definition of the profession.
     

UNITED KINGDOM

xxiv. The UK National Institute for Health and Care Excellence (NICE)

  • Pain - NICE recommends ACT for people aged 16 years and over with chronic primary pain. (click here for the full report).
  • Tinnitus - NICE recommends group-based ACT for tinnitus-related distress. (click here for the full report).
     

xxv. The British Pain Society, Guidelines for Pain Management Programmes for Adults (2021)

  • Recommends Acceptance-based approaches, including ACT. Grade of Recommendation: A
     

WORLDWIDE

xxvi. International College of Obsessive-Compulsive Spectrum Disorders (ICOCS), 2025 CANMAT-ICOCS International Guidelines for the Management of Patients with OCD

  • ACT is a second line psychological intervention for OCD. Level of Evidence: 2
     

xxvii. OCD Foundation, OCD Treatment Guide

  • Recommends ACT as a second-line treatment and also as an adjunctive treatment for obsessive compulsive disorder
     
2. Peer reviewed assessments of the ACT evidence base

A list of meta-analyses, systematic, narrative, or scoping reviews of the ACT evidence base, either overall or in specific areas, can be found here. The list is presented in reverse chronological order, by year of publication. There are now a handful of meta-analyses of meta-analyses (e.g., Gloster et al., 2020) -- a kind of a super summary. As of early 2026, there are over 600 meta-analyses, systematic reviews, narrative reviews, and scoping reviews on the list and it is growing very rapidly.

3. Mediational analyses

ACT is a process-oriented approach and the list of studies testing mediation or moderation is large and is rapidly growing. The list can be found here.

A review of the entire world's literature of successful mediational analyses of all forms of psychosocial intervention for mental health outcomes found that psychological flexibility (including closely related concepts such as mindfulness) accounted for well more than half of all replicated research findings (https://pubmed.ncbi.nlm.nih.gov/35863243/). If allowed to expand to fit the Extended Evolutionary Meta-Model, psychological flexibility and its social and bodily counterparts can address virtually all know and replicated processes of change.

4. Qualitative Research

Qualitative work is hard to do but it has continued throughout the ACT research program. A list can be found here. If you find any qualitative studies, please send them to ACBS staff to add to the list.

5. ACT Randomized Controlled Trials

Click here for ACT RCT studies. As of early 2026 there are more than 1,450 ACT randomized controlled trials.

6. More Evidence

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