Cognitive behavioural approach to functional neurological disorder: a systematic review, meta-analysis and grounded theory study
Revell, Emily R.
Introduction: Functional neurological symptoms are commonly reported by people presenting to neurology services. Symptoms are diverse, and there is little published evidence to inform treatment guidelines. Idiopathic drop attacks are also seen within neurology services, but literature about them is sparse and it is unclear whether they should be considered within the spectrum of functional neurological disorder. Aims: The aim of this thesis was to assess cognitive behavioural therapy (CBT) as an intervention for functional neurological disorder (FND), through a systematic review and meta-analysis. A second aim was to look at idiopathic drop attacks and determine whether a psychological understanding of these would help to inform formulation and treatment. Methods: A systematic review identified 28 studies of CBT for FND, nine of which were included in meta-analysis. In addition, a grounded theory study of idiopathic drop attacks was conducted through the coding and synthesis of data from interviews and diaries of seven individuals with FND, with the aim of identifying predisposing, precipitating and maintaining factors. Results: In the systematic review and meta-analysis, random effects models revealed a significant advantage of CBT over control on daily functioning, and a significant improvement within CBT groups over time. CBT also had a significantly positive effect on anxiety, depression and functional neurological symptoms, both compared to control groups, and within CBT groups over time. Positive effects of CBT were maintained over six months. In the grounded theory study, themes relating to predisposing and precipitating factors for drop attacks, along with thoughts, emotions and behaviour both before and after a fall, were identified. A cognitive behavioural model was proposed, with a traumatic first fall and life stressors as predisposing factors, situational triggers and increased worry as precipitating factors, and a maintaining cycle of thoughts, emotion and behaviour. Conclusions: Meta-analysis suggests that CBT may be effective for FND, and that the positive impact of this persists over time. However, as the evidence base is currently small, larger trials are required. The grounded theory study proposed a cognitive behavioural understanding of the onset and maintenance of idiopathic drop attacks and noted considerable overlap between drop attacks and non-epileptic seizures. This understanding could help to guide formulation, and suggests a CBT treatment approach would be worth exploring in this population.