Functional Neurological Disorder (FND) is a condition in which people experience
neurological symptoms, such as seizures; movement difficulties; or sensory changes, that are not explained by structural or electrical problems within the brain. One presentation observed in those with FND are Functional Dissociative Seizures (FDS), which resemble epileptic seizures but occur without measurable biological markers. Both conditions significantly impact daily life, are associated with functional disability, and are often linked with psychological disorders.
This thesis explored the relationship between functional conditions and psychological
disorders in two ways. The first study reviewed 34 papers examining how often post-traumatic stress disorder (PTSD) occurs in people with FDS. As individual study results vary, a meta-analysis was conducted; bringing together findings to generate a clearer co-occurrence estimate. Results highlight approximately one third of people with FDS meet the criteria for PTSD, a rate much higher than observed in the general population. Whilst PTSD appears important in the FDS population, it is not universal. This highlights that other biological; psychological; and social factors should be considered as playing a role in the onset and maintenance of the disorder.
The second study conducted network analysis on FND clinical data, gathered from
individuals who attended a neuro-psychotherapy service in England, UK. This allowed exploration of how psychological and functional symptoms relate to each other, in an estimated FND network. Results found PTSD symptoms; low self-efficacy; and difficulties in relationships, were the most connected symptoms within the network, suggesting these areas as potential intervention targets. Together, these studies indicate that trauma-related symptoms; self-perception; and relational functioning are important factors to consider in FND. Clinically, findings support the use of trauma-informed therapies, such as trauma-focused cognitive behavioural therapy (CBT); eye movement desensitisation and reprocessing therapy (EMDR); or interpersonal psychotherapy (IPT), in those with functional neurological and dissociative seizure disorders.
