Six-month outcomes of the CODES randomised controlled trial of cognitive behavioural therapy for dissociative seizures: A secondary analysis

Laura H. Goldstein, Emily J. Robinson, Trudie Chalder, Markus Reuber, Nick Medford, Jon Stone, Alan Carson, Michele Moore, Sabine Landau

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

PURPOSE: The CODES Trial for adults with dissociative seizures had a predesignated 12-month post-randomisation follow-up point for outcome evaluation. We undertook an exploratory, unplanned, secondary analysis to evaluate the effectiveness of cognitive behavioural therapy plus standardised medical care (CBT+SMC) compared to SMC alone at 6 months post-randomisation, i.e., closer to the end of treatment.

METHODS: The analysis of 6-month data followed our previous method of using multiple imputation and an intention-to-treat approach to analyse variables 12 months post-randomisation.

RESULTS: The original trial primary outcome of monthly seizure frequency showed greater benefit from CBT+SMC than SMC-alone at 6 months (at p < 0.05). Of 13 comparable previously-defined secondary outcomes, 12 showed a significant between group effect (p < 0.05) in favour of the CBT intervention at 6 months. The average effect size of the comparable previously-defined primary and secondary continuous outcomes was 0.33 at 6 months vs 0.26 at 12 months. The estimated Incidence Rate Ratio (IRR) quantifying monthly seizure reduction was IRR = 0.72 (95%CI from 0.55 to 0.93) at 6 months compared to IRR = 0.78 at 12 months.

CONCLUSION: DS-specific CBT (plus SMC) produced evidence of significant benefits at 6 months post- randomisation (around which time CBT was complete) compared to SMC alone; for the majority of these outcomes, better results following CBT (plus SMC) had previously been reported at 12 months. Our pattern of results suggests that short- and longer-term follow-ups are necessary to understand treatment effects in this disorder. Studies only providing short-term follow-up data should be interpreted with caution.

Original languageEnglish
Pages (from-to)128-136
JournalSeizure - European Journal of Epilepsy
Early online date25 Jan 2022
Publication statusPublished - Mar 2022

Keywords / Materials (for Non-textual outputs)

  • Cognitive behavioural therapy
  • Dissociative seizures
  • Outcomes
  • Randomised controlled trial


Dive into the research topics of 'Six-month outcomes of the CODES randomised controlled trial of cognitive behavioural therapy for dissociative seizures: A secondary analysis'. Together they form a unique fingerprint.

Cite this