Faulkner, JoshProuty, DevinDevlin, LucyAppleton, DamienRoche, MareeBelow, KarenMoffat, JohnSnell, DeborahWilliams, Matt NBarker-Collo, SuzanneTheadom, Alice2025-02-272025-02-272025-02-16BMJ Open, ISSN: 2044-6055 (Print); 2044-6055 (Online), BMJ, 15(2), e089727-. doi: 10.1136/bmjopen-2024-0897272044-60552044-6055http://hdl.handle.net/10292/18773OBJECTIVES: This study aimed to determine the feasibility of recruiting, implementing and delivering an acceptance and commitment therapy (ACT) intervention for mild traumatic brain injury (mTBI) (ACTion-mTBI) within a multidisciplinary outpatient mTBI rehabilitation services. The study also aimed to conduct a preliminary investigation of group differences between ACTion-mTBI and an equivalent cognitive behavioural therapy (CBT) intervention on various outcome measures and psychological treatment targets. DESIGN: A two-arm quasiexperimental feasibility study. SETTING: Five mTBI rehabilitation clinics throughout New Zealand. INTERVENTION: Psychologists working in mTBI rehabilitation clinics throughout New Zealand were trained to deliver ACTion-mTBI or CBT. Eligible participants were assigned to either of these interventions based on the psychologist available at the clinic they were referred to. ACTion-mTBI is a five sessions intervention that incorporates all six components of the ACT model. The CBT intervention is an equivalent intervention and incorporating all four components of the CBT model. Both interventions are adapted for an mTBI context. PRIMARY OUTCOME MEASURES: The primary outcomes were related to the feasibility of ACTion-mTBI. This included recruitment, retention and treatment adherence of participants, study procedure and fidelity of treatment delivery. SECONDARY OUTCOME MEASURES: To explore group differences between ACTion-mTBI and CBT on functional disability, postconcussion symptoms, mental health, valued living and psychological flexibility. RESULTS: The intervention proved feasible to implement with community-based mTBI rehabilitation services. Attrition rates were comparable between the two psychological interventions and fidelity to the treatments was high. At post-treatment, when covarying pretreatment scores, ACTion-mTBI had a significantly greater improvement in functional disability than CBT (moderate effect). ACTion-mTBI also had a significantly greater reduction in postconcussion symptoms, anxiety and stress. Promisingly, significant improvements in psychological flexibility was also found post-treatment. There were no group differences on depressive symptoms and valued living. CONCLUSION: We conclude that a full clinical trial of ACTion-mTBI for individuals with mTBI is feasible and warranted. TRIAL REGISTRATION NUMBER: ACTRN1262100059482.© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group. http://creativecommons.org/licenses/by-nc/4.0/. This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.http://creativecommons.org/licenses/by-nc/4.0/Brain InjuriesFeasibility StudiesPsychosocial Intervention4201 Allied Health and Rehabilitation Science5203 Clinical and Health Psychology42 Health Sciences52 PsychologyMind and BodyMental IllnessNeurosciencesTraumatic Head and Spine InjuryPhysical Injury - Accidents and Adverse EffectsBehavioral and Social ScienceClinical Trials and Supportive ActivitiesBrain DisordersRehabilitationMental HealthClinical ResearchDepression6.6 Psychological and behavioural5.6 Psychological and behaviouralMental health3 Good Health and Well Being1103 Clinical Sciences1117 Public Health and Health Services1199 Other Medical and Health Sciences32 Biomedical and clinical sciences42 Health sciences52 PsychologyHumansFeasibility StudiesAdultFemaleMaleAcceptance and Commitment TherapyNew ZealandBrain ConcussionMiddle AgedCognitive Behavioral TherapyYoung AdultTreatment OutcomeHumansFeasibility StudiesAdultFemaleMaleAcceptance and Commitment TherapyNew ZealandBrain ConcussionMiddle AgedCognitive Behavioral TherapyYoung AdultTreatment OutcomeJournal ArticleOpenAccess10.1136/bmjopen-2024-089727