We recently covered the publication of a large randomized controlled trial (RCT) in Lancet Psychiatry examining the treatment of patients with dissociative seizures using cognitive behavioral therapy (CBT).1 According to results of this study, patients did not experience greater improvements in monthly seizure frequency with CBT compared to standardized medical care. However, patients in the CBT group did demonstrate better outcomes on several secondary measures.
To dig deeper into the study and its importance for a growing field, we spoke with Laura H. Goldstein, PhD, of the Department of Psychology, King’s College London, United Kingdom. The following Q&A was edited for clarity and length.
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What is the significance of your study on CBT for patients with dissociative seizures,1 recently published in Lancet Psychiatry?
In funding this study, the National Institute for Health Research Health Technology Assessment Programme recognized that it was important to investigate ways of improving treatment for people with dissociative seizures (also called functional seizures). This was a major recognition for this patient group, for whom evidence-based care pathways are not consistently available either in the UK or globally.
It is the only large, multicenter RCT that has been undertaken for people with dissociative seizures and has shown that it is possible to undertake studies of this size and scope in this population. Completing a study of this size and scope raises the strength of evidence for psychological interventions for people with dissociative seizures. It also shows that it is possible to involve neurologists, liaison psychiatrists, neuropsychiatrists, and therapists in the care of people with dissociative seizures to provide a care pathway that involves multispecialty input.
While there appeared to be an overall reduction in how often people in both groups were having dissociative seizures with no clear difference between the groups at the end of the study, the group who had received CBT reported more consecutive days free from dissociative seizures in the last 6 months of the study and functioned better across a range of everyday situations. They described their dissociative seizures as less bothersome, were less distressed, reported better health and fewer symptoms, and were more satisfied with their treatment. They and their doctors also felt they had shown more improvement than the group who had received only standardized medical care.
Thus, even though there was not a significant difference between groups in terms of monthly numbers of dissociative seizures at the end of the study, the group who received CBT seemed to be better able to deal with their seizures and function on an everyday basis. We feel the study has shown the importance of providing dissociative seizure-specific CBT — as well as specialist medical care from neurologists and psychiatrists — to treat people with dissociative seizures.
Your 2010 pilot RCT published in Neurology found significant reductions in seizure frequency with CBT vs standard care.2 What factors may account for the difference in findings between that study and your current study?
Our 2010 study found a reduction in seizure frequency in the CBT plus standard medical care group relative to the standard medical care group at the end of treatment (roughly corresponding to the 6-month follow up point in our new study), but the difference in dissociative seizure frequency between the 2 groups was not significant at the end of that study. In our new study, because we focused on the difference between the groups at the 12 month follow-up, which is a stringent test of our interventions, we cannot currently say whether the CBT group showed significantly fewer dissociative seizures at the 6-month follow-up point. However, the pattern at the end of both studies was very similar.
CBT may provide some secondary benefits, including better quality of life, less psychological distress, and fewer somatic symptoms. Do these benefits justify broader provision of CBT in this population?
We feel that these benefits do justify broader provision of our model of CBT. Being able to function better and feeling less bothered by seizures, even if they are persisting, may be valuable for many people. It may also help patients develop techniques to plan for future situations where they may be at risk of relapse.
Are there any potential weaknesses inherent to CBT’s approach to treating this condition?
It is important to realize that our CBT package was developed to specifically treat people with dissociative seizures. Therefore, we are not talking about applying ‘general’ CBT or specifically CBT for anxiety/depression or another condition. Our dissociative seizure-specific CBT offers the opportunity to address many of the factors that have led to the development and maintenance of dissociative seizures. What we will be trying to work out from our data is who benefitted from the intervention and who did not, and why the intervention worked. That may help us understand what the limitations are for certain people and provide more guidance to therapists.
Are there any other forms of psychotherapy that may be promising for patients with dissociative seizures?
Many clinicians consider CBT to be helpful, but there are other models of psychotherapy that are being raised as potentially beneficial. A number of these are mentioned by David Perez, MD, who wrote a commentary to our paper.3 The difficulty, however, is that the strength of the research evidence for the use of these other psychotherapeutic approaches for people with dissociative seizures is not very strong, as no large scale RCTs focusing on people with dissociative seizures have been conducted for these other approaches.
While many clinicians have experience working with these other approaches and may feel that they work, or while small studies without adequate control groups may have shown promise, it would be inadvisable to widely recommend treatments only based on intuition/personal clinical experience or only based on very small studies of selected groups of patients rather than on a strong evidence base. Although we acknowledge conducting studies on the scale of the CODES trial is difficult, we would really hope that treatments are evaluated as rigorously as possible, as this is really important for the patients we seek to help.
1. Goldstein LH, Robinson EJ, Mellers JDC, et al. Cognitive behavioural therapy for adults with dissociative seizures (CODES): a pragmatic, multicentre, randomised controlled trial. Lancet Psychiatry. 2020;7:491-505.
2. Goldstein LH, Chalder T, Chigwedere C, et al. Cognitive-behavioral therapy for psychogenic nonepileptic seizures: a pilot RCT. Neurology. 2010;74:1986–94.
3. Perez, DL. The CODES trial for dissociative seizures: a landmark study and inflection point. Lancet Psychiatry. 2020;7(6):464-465.