Introduction: There is a dearth of literature on third-wave Cognitive Behavioural Therapies (CBT) for Functional Neurological Disorder (FND). These approaches adopt a transdiagnostic approach to support people to change their relationship with their psychological experiences (Hayes, 2004). This thesis examines the existing literature regarding these approaches and explores the impact of a Clinical Health Psychology Service two-phase psychological intervention for FND. This consists of assessment and formulation sessions (Phase 1) and an innovative seven-week Acceptance and Commitment Therapy (ACT) group (Phase 2).
Aims: A scoping review explores the extent and nature of the literature on third-wave CBT for FND and determines whether there is good quality evidence available regarding its effectiveness. Preliminary factors for intervention feasibility, acceptability and effectiveness are explored within the review. The empirical study aims to evaluate the impact and experiences of participants receiving the two-phase psychological intervention for FND.
Methods: A broad scoping review of third-wave CBT for FND was carried out on the bibliographic databases PsychINFO, EMBASE and MEDLINE, which were searched from the earliest listing up to June 2020. Key information is charted and explores factors related to intervention feasibility, acceptability and effectiveness. For the two-phase psychological intervention, pre and post standardised outcome measures are explored for three participants who attended assessment and formulation and three participants who attended the ACT group and participated in a Single Case Experimental Design (SCED). Seven participants completed a semi-structured Change Interview (Elliott, 1999; Elliott et al., 2001) regarding their experiences of the intervention and perceived changes, explored through thematic analysis (Braun & Clarke, 2006).
Results: The scoping review found a small number of low-quality studies have applied third-wave CBT in different formats across several FND presentations. All lacked information on feasibility and acceptability. There was promise for third-wave CBT effectiveness with improvements found for QoL, distress and psychological flexibility measures for some. The study found that changes in standardised outcome measures following each phase of the two-phase psychological intervention were complicated with a mixture of improvement, lack of change and, in some cases, worsening on standardised measures. In contrast, participants' interview accounts described the intervention positively and detailed important therapeutic changes attributable to the intervention.
Conclusion: Third-wave CBT is not well established for FND. While some patients benefit from these approaches, it is unclear what factors influence effectiveness. Higher quality intervention studies are required and could be developed through feasibility studies and qualitative research on different patient's perceptions and experiences of psychological intervention. The results from the two-phase psychological intervention for FND highlight the challenges of providing psychological intervention for a complex and heterogeneous clinical population.
