Introduction

Progressive neurological conditions, encompassing a spectrum of neurodegenerative diseases, present one of the most profound challenges in modern healthcare. These conditions, including Alzheimer’s disease, Parkinson’s disease, multiple sclerosis (MS), Huntington’s disease (HD), and motor neuron disease (MND), share a common trajectory of irreversible decline in physical, cognitive, and often emotional functioning. For individuals receiving such diagnoses and their families, the psychological burden is immense, characterised by grief, anxiety, depression, and the daunting task of maintaining a sense of meaning and identity amidst progressive loss (Schriger et al., 2025).

Traditional cognitive-behavioural approaches, with their emphasis on modifying or “fixing” maladaptive thoughts, may inadvertently communicate that psychological distress is an aberration to be eliminated, a message that can feel invalidating when distress is a natural response to an incurable, deteriorating condition. Acceptance and Commitment Therapy (ACT; pronounced “act”) offers a fundamentally different paradigm. As a “third-wave” cognitive-behavioural intervention, ACT shifts the focus from symptom reduction to cultivating psychological flexibility: the capacity to remain in contact with the present moment, consciously accepting painful inner experiences, and persisting in or changing behaviour in the service of chosen values (Schriger et al., 2025). This essay explores the application of ACT across the spectrum of progressive neurological conditions, drawing on contemporary clinical research to demonstrate its potential as a compassionate, scalable, and effective approach to supporting this population.

Understanding Progressive Neurological Conditions

Progressive neurological disorders, also termed neurodegenerative diseases, are chronic conditions characterised by the gradual, irreversible damage and destruction of neurons within the nervous system (Brain Injury SA, 2025). They are permanent conditions with no known cure, although medical advances can, in some instances, slow disease progression or manage symptoms. The estimated global prevalence exceeds 50 million people, a figure expected to rise with population ageing (MRC Clinical Trials Unit at UCL, n.d.).

The conditions encompass a diverse group, each with distinct aetiologies and symptomatology.

Dementia-type diseases, such as Alzheimer’s disease and frontotemporal dementia, are characterised by progressive neuronal death affecting memory, executive function, language, and personality. While traditionally viewed through a purely neurodegenerative lens, emerging research suggests that immune system dysfunction, specifically innate immune responses involving amyloid-beta, may play a role in the pathogenesis of Alzheimer’s disease, with some researchers proposing it as a form of innate autoimmune disorder (Global Autoimmune Institute, 2025).

Parkinsonism-type diseases, including Parkinson’s disease, result from damage to neurons that produce dopamine, leading to motor symptoms such as tremor, rigidity, bradykinesia, and postural instability. Recent immunological research has revealed that T cells in individuals with Parkinson’s disease recognise alpha-synuclein peptides and PINK1 proteins, mounting an autoimmune attack on dopamine-producing neurons years before clinical diagnosis becomes apparent (Global Autoimmune Institute, 2025). This finding suggests that the neurodegenerative process may begin long before motor symptoms emerge.

Demyelinating diseases, with multiple sclerosis as the prototypical example, involve autoimmune-mediated damage to the myelin sheath that insulates neurons. This disrupts neural signal transmission, causing a wide range of neurological symptoms that may follow a relapsing-remitting or progressive course. MS is the established model of a neurodegenerative autoimmune disease, with autoantibodies detectable up to ten years prior to symptom onset (Global Autoimmune Institute, 2025).

Motor neuron disease (MND), also known as amyotrophic lateral sclerosis (ALS), involves the degeneration of neurons controlling voluntary muscle movement. This leads to progressive paralysis affecting mobility, speech, swallowing, and eventually respiration, while typically preserving cognitive and sensory function (Brain Injury SA, 2025). The contrast between an intact mind and a failing body creates unique psychological challenges related to loss of agency.

Huntington’s disease is an autosomal-dominant genetic disorder characterised by the progressive loss of both mental and physical capacities. Involuntary choreiform movements, cognitive decline, and psychiatric symptoms, including depression, anxiety, irritability, and apathy, co-occur, creating complex biopsychosocial challenges for individuals and their families (Schriger et al., 2025). As a genetic condition with 50% inheritance risk, the psychological burden extends to at-risk relatives who face uncertainty about their own status.

Despite their differing pathophysiologies, these conditions share common challenges: progressive loss of function, uncertain disease trajectories, the need for increasing care dependency, and the threat to personal identity and meaning (Kudlicka, 2025). It is within this shared landscape of irreversible loss that ACT finds its most compelling application.

Acceptance and Commitment Therapy: Core Principles

ACT is an experiential, action-oriented psychotherapy that cultivates psychological flexibility through six interconnected processes (Schriger et al., 2025). Unlike traditional CBT, which focuses on evaluating and changing the content of thoughts, ACT aims to change one’s relationship with painful thoughts, feelings, and struggles, enabling individuals to pursue a meaningful life even in the face of unchangeable circumstances.

The six core processes are:

1. Values represent what one stands for, who one wants to be, and how one wants to live. Unlike goals, values cannot be “checked off” but serve as ongoing directions that can be accessed at any moment, regardless of circumstances. Values clarification involves identifying what is truly important beyond the constraints of the illness, distinguishing what one “should” care about from what is centrally meaningful (Schriger et al., 2025).

2. Acceptance involves being open to painful inner experiences rather than avoiding them. In the context of progressive neurological conditions, acceptance begins with letting go of attempts to “fix” the disease and acknowledging that life can continue meaningfully even with the condition (Schriger et al., 2025).

3. Committed Action refers to living in line with one’s values through concrete steps, adapting how values are pursued as physical and cognitive abilities change over time. This may involve “showing up” for values in novel ways, pursuing connection through video calls when mobility is limited, or accessing adventure through virtual experiences when physical activities are no longer possible (Schriger et al., 2025).

4. Contact with the Present Moment involves mindful awareness of the here and now, noticing thoughts, emotions, and physical sensations without judgment. This skill helps individuals avoid becoming entangled in regrets about lost function or anxieties about future decline (Schriger et al., 2025).

5. Defusion involves separating from painful thought content, recognising that thoughts are simply thoughts, not inherently true or false, and not necessarily directives for action. Defusion techniques help individuals observe thoughts about their condition, such as “I am only going to get worse,” without those thoughts dictating behaviour or extinguishing meaning (Schriger et al., 2025).

6. Self-as-Context refers to the observing self, the consistent perspective that has witnessed all of one’s experiences throughout life. This process helps individuals recognise that they are larger than and separate from their diagnosis, their symptoms, and their changing circumstances (Schriger et al., 2025).

These processes are not delivered sequentially but interwoven throughout therapy using metaphors, experiential exercises, and mindfulness practices that can be tailored to the individual’s cognitive and physical capabilities (Schriger et al., 2025).

The Rationale for ACT in Progressive Neurological Conditions

ACT is particularly well-suited for individuals with progressive neurological conditions for several reasons. First, these conditions cannot be fixed or cured; any therapeutic approach that implies distress is an aberration to be eliminated risks invalidating the genuine suffering inherent in these circumstances. ACT’s emphasis on acceptance aligns with the reality that grief, anxiety, and sadness are natural responses to progressive loss, not symptoms to be eradicated but experiences to be held with compassion (Huntington’s Disease Association, 2024).

Second, the transdiagnostic nature of ACT means it can address the complex, overlapping psychological presentations common in this population, including depression, anxiety, adjustment difficulties, and existential distress, without requiring separate protocols for each (Schriger et al., 2025). This is particularly valuable given the heterogeneous symptom profiles across and within conditions.

Third, ACT’s focus on values and committed action provides a framework for maintaining meaningful engagement even as physical and cognitive functions decline. By distinguishing values from specific goals, individuals can continue to “show up” for what matters to them in ways that adapt to changing capabilities (Schriger et al., 2025). This contrasts with approaches that may inadvertently communicate that a meaningful life is only possible if symptoms improve.

Fourth, the flexibility of ACT delivery, adaptable to in-person, telehealth, individual, or group formats, and variable in duration, makes it accessible to individuals with varying levels of disability and geographic access (Esiason et al., 2025; Schriger et al., 2025).

Clinical Applications and Evidence

Huntington’s Disease

The application of ACT to Huntington’s disease has received particular attention, reflecting the profound psychological burden of this genetic, multi-system disorder. A narrative review and case report by Schriger et al. (2025) documented the application of a six-session, virtually-delivered ACT intervention for a 52-year-old man with HD, accompanied by his caregiver. The intervention yielded clinically significant reductions in depressive symptoms, from moderate to mild on the PHQ-9, and cognitive fusion, alongside improvements in quality of life across physical functioning, mood, and worry domains.

The authors demonstrated how ACT processes could be tailored to HD-specific challenges. Values clarification involved disentangling what was truly important from limitations imposed by HD. For example, a patient who valued adventure but could no longer mountain bike identified alternative ways to access this value through virtual experiences, volunteering at bike races, or car rides with a caregiver. Acceptance work focused on letting go of attempts to “fix” the incurable condition while acknowledging the “new normal” of changing capabilities. Committed action involved flexible engagement with values on days when symptoms were more or less pervasive (Schriger et al., 2025).

The Huntington’s Disease Association has translated these principles into practice, developing three eight-week group ACT programmes tailored respectively for gene-positive individuals without manifest symptoms, caregivers of adults with HD, and caregivers of individuals with juvenile-onset HD. Preliminary outcomes from these programmes have demonstrated substantial improvements in low mood, anxiety, and quality of life, with 100% of participants recommending the programme for others and reporting positive personal benefit (Huntington’s Disease Association, 2024).

A key innovation in this work has been the inclusion of caregivers in the therapeutic process. Given the hereditary nature of HD, caregivers often face the dual burden of caring for a loved one while confronting their own genetic risk. The case report by Schriger et al. (2025) explicitly involved the caregiver in sessions, recognising that psychological flexibility for both parties is essential to maintaining relationship quality and managing the shared challenges of disease progression.

Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder

ACT has demonstrated robust efficacy in progressive MS and related conditions. A clinical trial of a six-session telehealth-delivered ACT intervention for individuals with neuromyelitis optica spectrum disorder (NMOSD), a rare autoimmune condition affecting the central nervous system, reported significant improvements across multiple outcomes (Esiason et al., 2025).

In a sample of 43 adults with NMOSD, pre-to-post treatment analysis revealed reductions in depression (BDI-II: 16.2 to 11.7, p < .001) and anxiety (BAI: 14.3 to 11.8, p = .043; GAD-7: 7.2 to 5.2, p < .009). Parallel improvements were observed in cognitive fusion (CFQ: 39.8 to 34.1, p < .001), psychological acceptance (AAQ-II: 20.1 to 17.2, p < .004), valued living (VLQ: 49.8 to 59.2, p < .001), and sleep quality (PSQI: 10.6 to 8.7, p < .001). Notably, improvements were maintained at three-month follow-up, and changes occurred independently of disability status, pain, or fatigue levels, suggesting that ACT targets modifiable psychological processes rather than simply reflecting physical improvement (Esiason et al., 2025).

These findings are significant for several reasons. First, they demonstrate that ACT can produce clinically meaningful improvements even in the context of stable or progressive physical disability; the disability status measure remained unchanged while psychological outcomes improved. Second, the telehealth delivery format proved feasible and effective, addressing access barriers for individuals with mobility limitations. Third, the inclusion of caregivers at any level of participation recognised the systemic impact of these conditions on family units.

Emerging Applications Across the Spectrum

The evidence base for ACT in progressive neurological conditions continues to expand. For motor neuron disease, ACT has been identified as a promising intervention for managing psychological distress associated with the rapid progression of disability, with its emphasis on values and acceptance providing a framework for maintaining meaning amidst profound loss (Schriger et al., 2025). The preservation of cognitive function in MND makes the experiential, metaphor-based approach of ACT particularly accessible.

For Parkinson’s disease, ACT has been applied to address the psychological burden of motor and non-motor symptoms, including depression, anxiety, and the challenge of maintaining identity as physical capabilities change. The emphasis on self-as-context, the observing self that persists beyond symptoms, can be particularly helpful when individuals struggle with a sense of being “defined by” their Parkinson’s (Schriger et al., 2025).

In dementia populations, the application of ACT requires adaptation to address cognitive impairment. Qualitative research exploring personal values in individuals with mild-to-moderate dementia found that although participants initially found defining values challenging, they could articulate meaningful values with support, reflecting on preserved aspects of identity and expressing appreciation for relationships and determination to “carry on” (Kudlicka, 2025). This suggests that values-based work is feasible and empowering even in the context of cognitive decline, provided practitioners are proactive in facilitating discussion and adapting to cognitive limitations.

For functional cognitive disorder, a condition involving subjective cognitive complaints without neurodegenerative pathology, a randomised controlled feasibility trial of online group ACT demonstrated promising results. The trial achieved 51.1% participation rate, with 81.8% of ACT participants attending at least four sessions and 64.3% reporting satisfaction compared to 0% in the treatment-as-usual group, with trends toward improvement in psychological flexibility and mood (Functional Cognitive Disorder Trial Group, 2025).

Practical Considerations for Implementation

Translating ACT principles into clinical practice with this population requires careful attention to the specific challenges posed by progressive neurological conditions.

Cognitive impairment presents a significant consideration. Traditional ACT relies on abstract thinking, metaphor comprehension, and the capacity to reflect on internal experiences, capacities that may be compromised in dementia, advanced MS, or HD. However, the Exeter systematic review found that individuals with cognitive impairment can still engage with ACT, particularly when interventions are adapted to use concrete language, repetition, visual aids, and involve caregivers in the process (Kudlicka, 2025). The focus on behavioural activation through values-based committed action may be more accessible than cognitive defusion exercises for individuals with executive dysfunction.

Physical disability requires adaptations to delivery format and content. Telehealth delivery has emerged as a particularly valuable modality, enabling individuals with mobility limitations to access therapy without the burden of travel (Esiason et al., 2025; Schriger et al., 2025). For individuals with communication difficulties, such as dysarthria in MND or HD, sessions may need to be shorter, allow for alternative communication methods, and incorporate caregivers to facilitate expression.

Caregiver involvement is essential given the progressive nature of these conditions and the inevitable shift toward care dependency. ACT interventions that explicitly include caregivers, as in the HD case report by Schriger et al. (2025), recognise that psychological flexibility must be cultivated within the caregiving dyad or family system, not merely within the individual. Caregivers face their own challenges of anticipatory grief, role strain, and, in genetic conditions like HD, personal risk. ACT provides a framework for addressing caregiver distress while aligning care efforts with shared values.

Timing of intervention matters. ACT may be valuable at multiple points across the disease trajectory: at diagnosis, to facilitate adjustment and values clarification; during transitions, such as loss of driving or need for care placement; and in advanced disease, to maintain meaning and connection. The Huntington’s Disease Association programmes are stratified by disease stage, pre-manifest, manifest, and caregiver, recognising that different challenges predominate at each phase (Huntington’s Disease Association, 2024).

Limitations and Future Directions

Despite the promising evidence, the ACT evidence base in progressive neurological conditions remains nascent. Several limitations warrant attention.

The existing literature comprises predominantly small-sample studies, case reports, and uncontrolled trials (Kudlicka, 2025; Schriger et al., 2025). While the NMOSD trial reported on 43 participants with controlled outcomes, and the functional cognitive disorder trial employed a randomised design, these remain exceptions. Larger, adequately powered randomised controlled trials are needed to establish efficacy definitively.

Heterogeneity across conditions poses challenges for generalisation. The cognitive, physical, and emotional profiles differ substantially between, for example, MND, with preserved cognition and rapid physical decline, and dementia, with impaired cognition and variable physical decline. Interventions must be tailored to condition-specific features, and evidence from one condition may not directly generalise to another.

Mechanism-focused research is needed to clarify whether ACT produces benefits through the theorised processes of psychological flexibility and cognitive defusion, or through non-specific factors such as therapeutic alliance, social connection in groups, or the simple act of being offered support. Studies that measure process measures such as the Cognitive Fusion Questionnaire (CFQ) and Acceptance and Action Questionnaire (AAQ-II) alongside outcomes, as in the NMOSD trial, are valuable for establishing mechanism (Esiason et al., 2025).

Implementation research is required to address questions of scalability, training requirements, and integration into routine care pathways. Telehealth delivery shows promise for improving access, but questions remain about digital literacy, technology access, and the therapeutic alliance in virtual formats.

Finally, the voices of individuals with progressive neurological conditions must be central in shaping future research. Qualitative studies, such as the Exeter exploration of personal values in dementia (Kudlicka, 2025), provide rich insights into how individuals experience these interventions and what aspects they find most meaningful. Participatory research approaches that involve individuals with lived experience in study design and outcome selection are essential for ensuring relevance and acceptability.

Conclusion

Progressive neurological conditions confront individuals and families with the profound challenge of living meaningfully in the face of irreversible loss. Acceptance and Commitment Therapy offers a compassionate, evidence-informed framework for meeting this challenge. By shifting focus from symptom elimination to psychological flexibility, cultivating acceptance, clarifying values, and taking committed action, ACT aligns with the realities of these conditions: they cannot be fixed, but life can still be rich with meaning.

The emerging evidence, while preliminary, is encouraging. Across Huntington’s disease, multiple sclerosis, NMOSD, and emerging applications in Parkinson’s, MND, and dementia, ACT interventions have demonstrated feasibility, acceptability, and promising signals of efficacy in reducing depression and anxiety, improving quality of life, and enhancing valued living. The transdiagnostic nature of ACT, its adaptability to different cognitive and physical capabilities, and its flexibility in delivery format make it well-suited to the heterogeneous needs of this population.

As the evidence base matures through larger trials and implementation research, ACT has the potential to become a cornerstone of psychosocial care for progressive neurological conditions, not as a treatment for the disease itself, but as a means of supporting individuals and families to live fully, meaningfully, and with psychological flexibility, from diagnosis through to the end of life. In the words of one ACT group participant, reflecting on their experience: “When you find bloody hell, it works” (Huntington’s Disease Association, 2024). This pragmatic optimism, grounded in the reality of limitation yet open to the possibility of meaning, captures the essence of ACT’s contribution to this challenging field.