An Evaluation of Acceptance and Commitment Therapy in Mild Traumatic Brain Injury

ACTion-mTBI is a manualised, five-session psychological intervention grounded in Acceptance and Commitment Therapy (ACT), specifically designed for individuals recovering from mild traumatic brain injury (mTBI), including concussion. The programme targets key outcomes such as functional disability, post-concussion symptoms, and psychological distress by enhancing psychological flexibility—the ability to remain present, open, and engaged with valued life activities despite difficult internal experiences. ACTion-mTBI was developed to align with New Zealand’s publicly funded concussion services, which typically provide five hours of psychological input under ACC contracts. As such, the programme is structured to be both brief and scalable, ensuring feasibility for real-world clinical implementation. Each of the five one-hour sessions targets specific ACT processes while also addressing the unique challenges of mTBI. Session one, Dropping the Struggle, introduces the ACT model and teaches acceptance and present moment awareness through mindfulness and metaphors. Session two, Moving Towards, focuses on values exploration and committed action using the “choice point” model to help participants reconnect with what matters most. Session three, Unhooking from the Mind, introduces cognitive defusion techniques and highlights the role of rigid thinking patterns in maintaining distress. Session four, The Noticing Self and Committing, helps develop a flexible sense of self and links values to meaningful goals through exercises like the values bullseye and SMART goal planning. The final session, Review and Relapse Prevention, integrates all ACT components, reinforces learning, and supports long-term maintenance through personalised action plans. Therapists delivering ACTion-mTBI are Registered Psychologists trained in the model and supported by a structured therapist manual and client workbook. The ACTion mTBI programme was co-designed through a collaborative and iterative process involving a diverse group of stakeholders to ensure clinical relevance, cultural responsiveness, and alignment with real-world service delivery. Stakeholders included psychologists with expertise in mTBI and ACT, Maori cultural advisors, researchers, and individuals with lived experience of concussion. The co-design process was structured around three 90-minute workshops delivered over a period of four weeks. During each workshop, participants were presented with proposed intervention content, such as ACT metaphors, session structure, and example therapeutic exercises. They were invited to provide structured and open-ended feedback on the clarity, cultural relevance, and perceived usefulness of these materials. Maori participants and cultural advisors contributed to the integration of matauranga Maori elements—such as the use of whakatauki, karakia, and Maori models of health—to enhance cultural alignment. Participants with lived experience of mTBI also shared personal insights into symptom burden and barriers to recovery, which directly informed the selection of session themes and examples used within the client workbook. Between sessions, feedback was collated and used to iteratively refine the intervention content. This included adapting language for clarity, tailoring metaphors to the mTBI context, and ensuring materials reflected diverse worldviews and values. The final intervention manual was reviewed by co-design participants before implementation in the feasibility trial. As this is a non-randomised, pragmatic trial, group allocation is determined based on psychologist availability at the site to which the participant is referred. Participants are assigned to one of the three intervention arms—ACTion mTBI, CBT-in-mTBI, or usual psychological care—according to the therapeutic approach delivered by the psychologist operating at that particular clinic. This approach reflects real-world service delivery within New Zealand’s ACC-funded concussion services, where treatment modality is typically guided by clinician training and availability rather than patient or referrer choice. Participants are not allocated based on personal preference, physician discretion, or clinical characteristics.