Undiagnosing and untreating psychogenic non epileptic seizures.
PhD thesis, University of Glasgow.
Full text available as:
Psychogenic nonepileptic seizures (PNES) can be defined as paroxysmal events that resemble epileptic seizures, without being associated with either abnormal electrical activity of the brain or primary physiological disturbances otherwise. It is estimated that about 10% of new presentations seen in an epilepsy clinic, and up to 30% of patients with intractable epilepsy will eventually be diagnosed as having PNES (Benbadis & Hauser, 2000).
Attributing a specific ‘cause’ to PNES is conceptually and clinically contentious but it seems reasonable to say that they represent a physical expression of psychological distress involving behaviour that the patient finds difficult or impossible to control or disavows as being intentional.
Most patients with PNES are initially thought to have epilepsy and treated with antiepileptic drugs (AED), sometimes for many years. Up to 40% of patients are inappropriately maintained on AEDs after the diagnosis of PNES has been established. As such, rather than being intrinsic to the condition, the widely reported poor outcomes associated with PNES may be substantially confounded by continued inappropriate medical management and iatrogenic harm.
Withdrawing or continuing antiepileptic medication in patients with PNES could have important physical and psychological consequences, which may affect the prognosis of the attack disorder. If this is the case, manipulating medication following the diagnosis of PNES may have a role in the management of this disorder. The work contained in this thesis aims to explore some aspects of the effects that continuing or withdrawing AED has on the course and outcome of PNES.
Following an initial general overview on the subject of PNES (chapter 1), a systematic review of the literature is presented in chapter 2; the conclusion being a lack of good quality and reliable evidence for the effects of AED treatment in patients with PNES and a need for further original research in this area. The rationale and programme of research is presented in chapter 3
Chapter 4 presents the results of a large observational study to establish the feasibility and safety of supervised AED withdrawal in patients with an established diagnosis of PNES. Only 3 of the 78 patients included reported a new type of event requiring the reintroduction of AED, and no serious medical events were reported. The study therefore shows that, with appropriate diagnostic investigations and surveillance during follow-up, withdrawal of AED can be achieved safely in patients with PNES.
A randomised controlled trial presented in chapter 5 aims to evaluate the potential therapeutic effect of AED withdrawal. Of the 25 subjects recruited, 14 were randomised to immediate withdrawal (IW) and 11 to delayed withdrawal (DW). Patients randomised to IW had a significant reduction in the use of emergency treatment for PNES, and a lower proportion was found to be using emergency services. The IW group also had a sustained reduction of attacks throughout the study and by 18 months post-diagnosis 50% were attack free as compared with 27% in the DW group.
The results of this exploratory trial suggested a possible therapeutic effect of AED withdrawal, with a sustained reduction of attacks following the withdrawal of medication, coupled with a significant reduction in health care utilisation and no evidence of any deterioration.
The last original paper presented in chapter 6 investigates the longer term psychosocial outcome of PNES with an observational study of the 25 patients included in the RCT. This study reports a significant improvement in some psychological measures; particularly in illness representations and mood, as well as for some measures of social adjustment.
The evidence presented in these three studies (chapter 4, 5 and 6) suggests that a clear delivery of the diagnosis of PNES, followed by AED withdrawal, is safe and has possible beneficial effects on the clinical and psychosocial outcome of PNES. In particular medication withdrawal in and of itself appears to be a helpful concomitant in the successful removal of an inappropriate label of label of epilepsy, reduces the potential for iatrogenic harm, may help patients to shift towards a more psychologically-based explanation, and is associated with positive psychosocial outcomes.
Finally, chapter 7 gives a summary of the main findings as well as discussing methodological limitations of the current research. The clinical implications of the evidence from this body of work are also discussed, as well as possible avenues for future research in the field.
Actions (login required)