Cognitive behavioural therapy for adults with dissociative seizures (CODES): a pragmatic, multicentre, randomised controlled trial

*Information supplied from Jon Stone Twitter Account

The CODES trial – a Randomised Controlled Trial of cognitive behavioural therapy for dissociative (functional) seizures has been published in Lancet Psychiatry. (“All figures are copyright and have been reproduced from the Lancet Psychiatry paper”)

Dissociative seizures (DS), also called Functional Seizures are one of the commonest forms of #FND. They look and feel a lot like epilepsy or faints, and cause disability and distress to those who have them. Around 1 in 7 people in a ‘first fit’ clinic have this diagnosis

DS have been ignored by clinicians and researchers for years, so we have had to devise new treatments from scratch in the last 10-15 years based on what we are still learning about the condition.

In the mid-2000s, Laura Goldstein, Trudie Chalder, John Mellers and colleagues from King’s College London started testing a type of cognitive behavioural therapy (CBT) specific for Dissociative Seizures, based in large part on earlier work by Trudie Chalder.

Their pilot trial – Cognitive-behavioral therapy for psychogenic nonepileptic seizures published in “Neurology” in 2010 in 66 people showed promising results.

This led to the CODES trial, a UK wide multicentre trial funded by NIHR Health Technology Assessment Programme who recognised that we needed better evidence to help the thousands of people who suffer from DS

Between 2015 and 2017, 368 people with dissociative seizures took part in the trial, agreeing to be randomised either to standardised medical care (SMC), or SMC plus 12 sessions of CBT (SMC+CBT). Thank you to all patients and clinicians who took part!

This is six time bigger than any previous trial for Dissociative Seizures, or any type of FND, and included centres from across the UK.

The figure below shows how we got to our 368 participants. Not everyone wanted to take part, some improved after seeing a neurologist, and others dropped out.

But overall, we found that people with Dissociative Seizures were keen to take part in the trial and had a high level of agreement with the diagnosis before treatment started.

So, drum roll…. What did we find?

The main result – at 12 months adding CBT did not lead to a reduced number of seizures patients reported every month compared to standardised medical care alone

The primary outcome of the study didn’t show an additional benefit for CBT. But you can see from the figure that both groups seemed to improve over time, with seizures roughly halving in frequency in each group

We had a range of secondary outcomes. Did patients themselves think they were better? Were they as bothered by their seizures? Did they have other physical symptoms?

On 8 of the 13 secondary measures shown below, patients who had CBT had better outcomes. They felt better, were more satisfied with their treatment and seizures didn’t bother them so much. They had improved general health and functioning.

In addition, although the CBT group had the same number of seizures, they had longer periods without seizures in the last 6 months of the study. This raises the issue of whether absolute number of seizures is the most meaningful outcome for patients.

So – what did we conclude? Adding CBT to standardised care didn’t result in fewer seizures, our primary outcome measure, compared to only having standardised medical care – but it did improve health across a range of measures.

Both groups’ seizure frequency seemed to have improved – perhaps that would have happened anyway without treatment – although we think it’s more likely that both standardised care and CBT helped.

The standardised medical care – careful explanation, provision of information and meetings with a doctor who has expertise in DS – is more than many people with DS get in many health care systems around the world.

This was not a trial comparing ‘doing something’ vs ‘doing nothing’ (which is what shockingly, often happens to people with DS)

We think that the CODES trial is a major piece of evidence supporting the need to provide neurology, psychiatry and psychology services for people with DS.

We have further papers to publish exploring the costs of treatment, and patient and therapist perception of treatment.

You can read more about the trial and see the CODES information booklets given to patients at
You can also read about the baseline group of 698 patients who saw neurologists in this paper

The CODES trial led by Laura Goldstein recruited a record breaking 698 people with Dissociative/FND seizures via 27 UK NHS centres for initial screening. Unique opportunity to establish some basic info about people with the condition.

Mean age of onset was 28yrs but PEAK age of onset was 19. This early peak was mainly in females (74%). Males developed it more steadily through life. Higher rates of socioeconomic deprivation than by chance but all groups represented. Median duration of events was 3 years.

and more detail about those 368 patients that took part in this new paper.

Thank you to all the patients, clinicians, NIHR Health Technology Assessment Programme and trial team especially Professor Laura Goldstein, King’s College London, who led this project for over 8 years, with unrelenting diligence and care, earning massive respect from everyone involved.

CODES Trial team included – John Mellers, Trudie Chalder, Emily Robinson, Jon Stone, Alan Carson, Markus Reuber, Paul McCrone, Nick Medford, Joanna Murray, Mark Richardson, Izabela Pilecka, Carole Eastwood, Michele Moore, Iris Mosweu, Iain Perdue and Sabine Landau.