Below is a partial list of studies with medational data.
See also these recent meta-analysis or reviews of ACT mediational studies or summaries of psychological flexibility as a mediator:
Murillo, C., Vo, T., Vansteelandt, S., Harrison, L. E., Cagnie, B. N., Coppieters, I., Chys, M., Timmers, I., & Meeus, M. (2022). How do psychologically based interventions for chronic musculoskeletal pain work? A systematic review and meta-analysis of specific moderators and mediators of treatment. Clinical Psychology Review, 94, 102160. DOI: 10.1016/j.cpr.2022.102160.
Hayes, S. C., Ciarrochi, J., Hofmann, S. G., Chin, F., & Sahdra, B. (2022). Evolving an idionomic approach to processes of change: Towards a unified personalized science of human improvement. Behaviour Research and Therapy, 156, 104155. Doi: 10.1016/j.brat.2022.104155
Stockton, D., Kellett, S., Berrios, R., Sirois, F., Wilkinson, N., & Miles, G. (2019). Identifying the Underlying Mechanisms of Change During Acceptance and Commitment Therapy (ACT): A Systematic Review of Contemporary Mediation Studies. Behavioural and Cognitive Psychotherapy, 47(3), 332-362. DOI: 10.1017/S1352465818000553
Ren, Z., Zhao, C., Bian, C., Zhu, W., Jiang, G., & Zhu, Z. (2019). Mechanisms of Acceptance and Commitment Therapy: A meta-analytic structural equation model. Acta Psychologica Sinica, 51(6), 662-676. DOI: 10.3724/SP.J.1041.2019.00662 Full text available on the ACBS website.
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MEDIATIONAL STUDIES
Ong, C.W., Woods, D.W., Franklin, M.E., Saunders, S.M., Neal-Barnett, A.M., Compton, S.N., & Twohig, M.P. (2023 in press). The role of psychological flexibility in acceptance-enhanced behavior therapy for trichotillomania: Moderation and mediation findings. Behaviour Research and Therapy. https://doi.org/10.1016/j.brat.2023.104302
Krafft, J., Petersen, J.M., Ong, C.W., Twohig, M.P., & Levin, M.E. (2023). Processes of change in online acceptance and commitment therapy for hoarding. Journal of Contextual Behavioral Science, 28, 198-206. https://doi.org/10.1016/j.jcbs.2023.04.001
Lakin, D. P., Cooper, S. E., Andersen, L., Brown, F. L., Augustinavicius, J. L. S., Carswell, K., Leku, M., Adaku, A., Au, T., Bryant, R., Garcia-Moreno, C., White, R. G., & Tol, W. A. (2023). Psychological flexibility in South Sudanese female refugees in Uganda as a mechanism for change within a guided self-help intervention.Journal of Consulting and Clinical Psychology, 91(1), 6–13. https://doi.org/10.1037/ccp0000774
Fishbein, J.N., Judd, C.M., Genung, S., Stanton, A.L., & Arch, J.J. (2022). Intervention and mediation effects of target processes in a randomized controlled trial of Acceptance and Commitment Therapy for anxious cancer survivors in community oncology clinics. Behaviour Research and Therapy, 153, 104103. DOI: 10.1016/j.brat.2022.104103
Bricker, J.B., Levin, M., Lappalainen, R., Mull, K., Sullivan, B., Santiago-Torres, M. (2021). Mechanisms of Smartphone Apps for Cigarette Smoking Cessation: Results of a Serial Mediation Model From the iCanQuit Randomized Trial. JMIR Mhealth Uhealth, 9(11), e32847. DOI: 10.2196/32847
A-Tjak, J.G.L., Morina, N., Topper, M. et al. (2021). One year follow-up and mediation in cognitive behavioral therapy and acceptance and commitment therapy for adult depression. BMC Psychiatry, 21, 41. DOI: 10.1186/s12888-020-03020-1
Levin, M.E., Krafft, J., & Twohig, M.P. (2020). Examining processes of change in an online acceptance and commitment therapy dismantling trial with distressed college students. Journal of Contextual Behavioral Science, 17, 10-16. https://doi.org/10.1016/j.jcbs.2020.05.001
Østergaard, T., Lundgren, T., Zettle, R.D., Landrø, N.I. & Haaland, V.Ø. (2020). Psychological Flexibility in Depression Relapse Prevention: Processes of Change and Positive Mental Health in Group-Based ACT for Residual Symptoms. Frontiers in Psychology, 11, 528. https://doi.org/10.3389/fpsyg.2020.00528
Räsänen, P., Muotka, J., & Lappalainen, R. (2018). Examining mediators of change in wellbeing, stress, and depression in a blended, Internet-based, ACT intervention for university students. Internet Interventions, 22, 100343. DOI: 10.1016/j.invent.2020.100343
Spidel, A., Lecomte,T., Kealy, D., & Daigneault, I. (2018). Acceptance and commitment therapy for psychosis and trauma: Improvement in psychiatric symptoms, emotion regulation, and treatment compliance following a brief group intervention. Psychology and Psychotherapy: Theory, Research, and Practice, 91, 248-261.
Lin Jiaxi; Klatt, Laura-Isabelle; McCracken, Lance M.; Baumeister, Harald (2018). Psychological flexibility mediates the effect of an online-based acceptance and commitment therapy for chronic pain: an investigation of change processes. Pain, 159(4), 663-672. doi: 10.1097/j.pain.0000000000001134
Pots, W.T.M., Trompetter, H.R., Schreurs, K.M.G. et al. (2016). How and for whom does web-based acceptance and commitment therapy work? Mediation and moderation analyses of web-based ACT for depressive symptoms. BMC Psychiatry,16, 158. DOI: 10.1186/s12888-016-0841-6
Vowles, K.E., Witkiewitz, K., Sowden, G., & Ashworth, J. (2014). Acceptance and Commitment Therapy for Chronic Pain: Evidence of Mediation and Clinically Significant Change Following an Abbreviated Interdisciplinary Program of Rehabilitation. The Journal of Pain, 15(1), 101-113. DOI: 10.1016/j.jpain.2013.10.002
Zettle, R. D., Rains, J. C., & Hayes, S. C. (2011). Processes of change in Acceptance and Commitment Therapy and Cognitive Therapy for depression: A mediation reanalysis of Zettle and Rains. Behavior Modification, 35(3), 265-283. – Originally published in: Zettle, R. D. & Rains, J. C. (1989). Group cognitive and contextual therapies in treatment of Depression. Journal of Clinical Psychology, 45, 438-445.
Bach, P., & Hayes, S. C. (2002). The use of acceptance and commitment therapy to prevent the rehospitalization of psychotic patients: A randomized controlled trial. Journal of consulting and clinical psychology, 70(5), 1129-1138.
Bach, P., Gaudiano, B.A., Hayes, S.C. & Herbert, J.D. (2013) Acceptance and commitment therapy for psychosis: intent to treat, hospitalization outcome and mediation by believability. Psychosis, 5(2), 166-174. DOI: 10.1080/17522439.2012.671349
Gaudiano, B. A., & Herbert, J. D. (2006). Acute treatment of inpatients with psychotic symptoms using Acceptance and Commitment Therapy: Pilot results. Behaviour research and therapy, 44(3), 415-437.
Gifford, E. V., Kohlenberg, B. S., Hayes, S. C., Antonuccio, D. O., Piasecki, M. M., Rasmussen-Hall, M. L., & Palm, K. M. (2004). Acceptance-based treatment for smoking cessation. Behavior therapy, 35(4), 689-705.
Hayes, S.C., Bissett, R., Roget, N., Padilla, M., Kohlenberg, B.S., Fisher, G., Masuda, A., Pistorello, J., Rye, A.K., Berry, K., & Niccolls, R. (2004). The impact of acceptance and commitment training and multicultural training on the stigmatizing attitudes and professional burnout of substance abuse counselors. Behavior Therapy, 35(4), 821-835.
Lundgren, T., Dahl, J., Melin, L., & Kies, B. (2006). Evaluation of acceptance and commitment therapy for drug refractory epilepsy: a randomized controlled trial in South Africa—a pilot study. Epilepsia, 47(12), 2173-2179.
Lundgren, T., Dahl, J., & Hayes, S. C. (2008). Evaluation of mediators of change in the treatment of epilepsy with acceptance and commitment therapy. Journal of behavioral medicine, 31(3), 225-235.
Lillis, J., Hayes, S. C., & Levin, M. E. (2011). Binge eating and weight control: The role of experiential avoidance. Behavior modification, 35(3), 252-264.
Roemer, L., Orsillo, S. M., & Salters-Pedneault, K. (2008). Efficacy of an acceptance-based behavior therapy for generalized anxiety disorder: evaluation in a randomized controlled trial. Journal of consulting and clinical psychology, 76(6), 1083.
Hayes, S. A., Orsillo, S. M., & Roemer, L. (2010). Changes in proposed mechanisms of action during an acceptance-based behavior therapy for generalized anxiety disorder. Behaviour Research and Therapy, 48(3), 238-245.
Roemer, L., & Orsillo, S. M. (2007). An open trial of an acceptance-based behavior therapy for generalized anxiety disorder. Behavior therapy, 38(1), 72-85.
Varra, A. A., Hayes, S. C., Roget, N., & Fisher, G. (2008). A randomized control trial examining the effect of acceptance and commitment training on clinician willingness to use evidence-based pharmacotherapy. Journal of consulting and clinical psychology, 76(3), 449.
Wicksell, R. K., Ahlqvist, J., Bring, A., Melin, L., & Olsson, G. L. (2008). Can exposure and acceptance strategies improve functioning and life satisfaction in people with chronic pain and Whiplash‐Associated Disorders (WAD)? A randomized controlled trial. Cognitive behaviour therapy, 37(3), 169-182.
Wicksell, R. K., Olsson, G. L., & Hayes, S. C. (2010). Psychological flexibility as a mediator of improvement in Acceptance and Commitment Therapy for patients with chronic pain following whiplash. European Journal of Pain, 14(10), 1059-e1.
Lillis, J., Hayes, S. C., Bunting, K., & Masuda, A. (2009). Teaching acceptance and mindfulness to improve the lives of the obese: A preliminary test of a theoretical model. Annals of Behavioral Medicine, 37(1), 58-69.
Twohig, M. P., Hayes, S. C., Plumb, J. C., Pruitt, L. D., Collins, A. B., Hazlett-Stevens, H., & Woidneck, M. R. (2010). A randomized clinical trial of acceptance and commitment therapy versus progressive relaxation training for obsessive-compulsive disorder. Journal of consulting and clinical psychology, 78(5), 705.
Muto, T., Hayes, S. C., & Jeffcoat, T. (2011). The effectiveness of acceptance and commitment therapy bibliotherapy for enhancing the psychological health of Japanese college students living abroad. Behavior Therapy, 42(2), 323-335.
Gifford, E. V., Kohlenberg, B. S., Hayes, S. C., Pierson, H. M., Piasecki, M. P., Antonuccio, D. O., & Palm, K. M. (2011). Does acceptance and relationship focused behavior therapy contribute to bupropion outcomes? A randomized controlled trial of functional analytic psychotherapy and acceptance and commitment therapy for smoking cessation. Behavior therapy, 42(4), 700-715.
Weinland, S., Arvidsson, D., Kakoulidis, T., P., & Dahl, J. (2011). Acceptance and commitment therapy for bariatric surgery patients, a pilot RCT. Obesity Research & Clinical Practice, 6, e21-e30.
Weineland, S., Hayes, S. C., & Dahl, J. (2012). Psychological flexibility and the gains of acceptance‐based treatment for post‐bariatric surgery: six‐month follow‐up and a test of the underlying model. Clinical obesity, 2(1‐2), 15-24.
Luoma, J. B., Kohlenberg, B. S., Hayes, S. C., & Fletcher, L. (2012). Slow and steady wins the race: a randomized clinical trial of acceptance and commitment therapy targeting shame in substance use disorders. Journal of consulting and clinical psychology, 80(1), 43.
Jeffcoat, T., & Hayes, S. C. (2012). A randomized trial of ACT bibliotherapy on the mental health of K-12 teachers and staff. Behaviour research and therapy, 50(9), 571-579.
Westin et al., (2011). Acceptance and Commitment Therapy versus Tinnitus Retraining Therapy in the treatment of tinnitus distress: A radomised controlled trial. Behavior Research and Therapy, 49, 737-747.
Clarke, S., Kingston, J., James, K., Bolderston, H., & Remington, B. (2014). Acceptance and commitment therapy group for treatment-resistant participants: A randomized controlled trial. Journal of Contextual Behavioral Science, 3, 179-188.
Gratz, K. L., & Gunderson, J. G. (2006). Preliminary data on an acceptance-based emotion regulation group intervention for deliberate self-harm among women with borderline personality disorder. Behavior therapy, 37(1), 25-35.
Wicksell R. K., Melin, L., Lekander, M. & Olsson, G. L. (2009). Evaluating the effectiveness of exposure and acceptance strategies to improve functioning and quality of life in longstanding pediatric pain - A randomized controlled trial. Pain, 141, 248-257.
Wicksell, R. K., Olsson, G. L., & Hayes, S. C. (2011). Mediators of change in acceptance and commitment therapy for pediatric chronic pain. Pain, 152(12), 2792-2801.
Hayes-Skelton, S. A., Roemer, L., & Orsillo, S. M. (2013). A randomized clinical trial comparing an acceptance based behavior therapy to applied relaxation for generalized anxiety disorder. J Consult Clin Psychol., 81, 761-773.
Hayes-Skelton, S. A., Calloway, A., Roemer, L., & Orsillo, S. M. (2015). Decentering as a potential common mechanism across two therapies for generalized anxiety disorder. Journal of Consulting and Clinical Psychology, 83, 395-404.
White, R., Gumley, A., McTaggart, J., Rattrie, L., McConville, D., Cleare, S., & Mitchell, G. (2011). A feasibility study of Acceptance and Commitment Therapy for emotional dysfunction following psychosis. Behaviour research and therapy, 49(12), 901-907.
Wicksell, R. K., Kemani, M., Jensen, K., Kosek, E., Kadetoff, D., Sorjonen, K., ... & Olsson, G. L. (2013). Acceptance and commitment therapy for fibromyalgia: a randomized controlled trial. European journal of pain, 17(4), 599-611.
Morton, J., Snowdon, S., Gopold, M. & Guymer, E. (2012). Acceptance and commitment therapy group treatment for symptoms of borderline personality disorder: A public sector pilot study. Cognitive and Behavioral Practice.
Gregg, J. A., Callaghan, G. M., Hayes, S. C., & Glenn-Lawson, J. L. (2007). Improving diabetes self-management through acceptance, mindfulness, and values: a randomized controlled trial. Journal of consulting and clinical psychology, 75(2), 336.
Fledderus, M., Bohlmeijer, E. T., Fox, J. P., Schreurs, K. M. G., Spinhoven, P. (2012). The role of psychological flexibility in a self-help acceptance and commitment therapy intervention for psychological distress in a randomized controlled trial. Behaviour Research and Therapy, 51, 142-151.
Jensen et al. (2012). Cognitive behavioral therapy increases pain-evoked activation of the prefrontal cortex in patients with fibromyalgeia. Pain, 153, 1495-1503.
Wetherall et al. (2011). A randomized, controlled trial of acceptance and commitment therapy and cognitive-behavioral therapy for chronic pain. Pain, 152, 2098-2107.
Luciano et al. (2014). Effectiveness of group acceptance and comitment therapy for fibromyalgia: A 6-month randomized controlled trial (EFFIGACT study). Pain, 155, 693-702.
Arch, J. J., Eifert, G. H., Davies, C., Vilardaga, J. C. P., Rose, R. D., & Craske, M. G. (2012). Randomized clinical trial of cognitive behavioral therapy (CBT) versus acceptance and commitment therapy (ACT) for mixed anxiety disorders. Journal of consulting and clinical psychology, 80(5), 750.
Arch, J. J., Wolizky-Taylor, K. B., Eifert, G. H., & Craske, M. G. (2012). Longitudinal treatment mediation of traditional cognitive behavioral therapy and acceptance and commitment therapy for anxiety disorders. Behaviour Research and Therapy, 50, 469-478.
Cederberg, J. T., Cernvall, M., Dahl, J., von Essen, L., & Ljungman, G. (2016). Acceptance as a Mediator for Change in Acceptance and Commitment Therapy for Persons with Chronic Pain?. International journal of behavioral medicine, 23(1), 21-29.
Thorsell et al. (2011). A comparative study of 2 manual-based self-help interventions, acceptance and commitment therapy and applied relaxation, for persons with chronic pain. Clin J Pain, 27, 716-723.
Bricker, J., Wyszynski, C., Comstock, B., & Heffner, J. L. (2013). Pilot randomized controlled trial of web-based acceptance and commitment therapy for smoking cessation. Nicotine & Tobacco Research, 15, 1756-1764.
Luoma, J. B., & Vilardaga, J. P. (2013). Improving therapist psychological flexibility while training acceptance and commitment therapy: a pilot study. Cognitive behaviour therapy, 42(1), 1-8.
Hesser et al. (2012). A randomized controlled trial of internet-delivered cognitive behavior therapy and acceptance and commitment therapy in the treatment of tinnitus. Jounral of Consulting and Clinical Psychology, 80, 649-661.
Hesser, H., Westin, V. Z., Andersson (2014). Acceptance as a mediator in internet-delivered acceptance and commitment therapy and cognitive behavior therapy for tinnitus. J Behav Med, 37, 756-767.
Forman, E. M., Chapman, J. E., Herbert, J. D., Goetter, E. M., Yuen, E. K., & Moitra, E. (2012). Using Session-by-Session Measurement to Compare Mechanisms of Action for Acceptance and Commitment Therapy and Cognitive Therapy. Behavior Therapy, 43(2), 341-354.
Forman, E. M., Herbert, J. D., Moitra, E., Yeomans, P. D., & Geller, P. A. (2007). A randomized controlled effectiveness trial of acceptance and commitment therapy and cognitive therapy for anxiety and depression. Behavior modification, 31(6), 772-799.
Forman, E. M., Butryn, M. L., Juarascio, A. S., Bradley, L. E., Lowe, M. R., Herbert, J. D., & Shaw, J. A. (2013). The mind your health project: A randomized controlled trial of an innovative behavioral treatment for obesity. Obesity, 21, 1119-1126.
Gifford, E. V., & Lillis, J. (2009). Avoidance and inflexibility as a common clinical pathway in obesity and smoking treatment. Journal of health psychology, 14(7), 992-996.
Woods, D. W., Wetterneck, C. T., & Flessner, C. A. (2006). A controlled evaluation of acceptance and commitment therapy plus habit reversal for trichotillomania. Behaviour Research and Therapy, 44, 639-656.
Craske et al. (2014). Randomized controlled trial of cognitive behavioral therapy and acceptance and commitment therapy for social phobia: Outcomes and moderators. Journal of Consulting and Clinical Psychology, 82, 1034-1048. & Niles et al. (2014). Cognitive mediators of treatment fo social anxiety disorder: Comparing acceptance and commitment therapy and cognitive-behavioral therapy. Behavior Therapy, 45, 664-677.
Bond, F. W., & Bunce, D. (2000). Mediators of change in emotion-focused and problem-focused worksite stress management interventions. Journal of occupational health psychology, 5(1), 156.
Flaxman, P. E., & Bond, F. W. (2010). Worksite stress management training: Moderated effects and clinical significance. Journal of Occupational Health Psychology, 15(4), 347.
Flaxman, P. E. & Bond, F. W. (2010). A randomised worksite comparison of acceptance and commitment therapy and stress inoculation training. Behaviour Research and Therapy, 48(8), 816-820.
Lloyd, J., Bond, F. W., & Flaxman, P. E. (2013). The value of psychological flexibility: Examining psychological mechanisms underpinning a cognitive behavioural therapy intervention for burnout. Work & Stress, 27(2), 181-199.
Zarling, A., Lawrence, E., & Marchman, J. (2015). A randomized controlled trial of acceptance and comitment therapy for aggressive behavior. Journal of Consulting and Clinical Psychology, 83, 199-212.
Juarascio, A., Shaw, J., Forman, E., Timko, C. A., Herbert, J., Butryn, M., Bunnell, D., Matteucci, A., & Lowe, M. (2013). Acceptance and Commitment Therapy as a Novel Treatment for Eating Disorders: An Initial Test of Efficacy and Mediation. Behavior Modification, 37(4), 459–489.
Rost, A. D., Wilson, K., Buchanan, E., Hildebrandt, M. J., & Mutch, D. (2012). Improving psychological adjustment among late-stage ovarian cancer patients: examining the role of avoidance in treatment. Cognitive and Behavioral practice, 19(4), 508-517.
Hawkes, A. L., Chambers, S. K., Pakenham, K. I., Patrao, T. A., Baade, P. D., Lynch, B. M., ... & Courneya, K. S. (2013). Effects of a telephone-delivered multiple health behavior change intervention (CanChange) on health and behavioral outcomes in survivors of colorectal cancer: a randomized controlled trial. Journal of Clinical Oncology, 31(18), 2313-2321.
Hawkes, A. L., Pakenham, K. I., Chambers, S. K., Patrao, T. A., & Courneya, K. S. (2014). Effects of a multiple health behavior change intervention for colorectal cancer survivors on psychosocial outcomes and quality of life: a randomized controlled trial. Annals of Behavioral Medicine, 48(3), 359-370.