Exploring ketamine as a treatment for people with anorexia and major depressive disorder: the EDEN study

What is the background to this study? 

The N-methyl-D-aspartate (NMDA) receptor antagonist drug ketamine has been found to have effective antidepressant effects in several populations and there is emerging interest in its potential as a treatment in the field of psychiatry. However, we know that more research is needed in specific subpopulations, such as those with anorexia nervosa, which is where the EDEN study comes in. 

It has long been acknowledged that common antidepressants (such as SSRIs and SNRIs) are mostly ineffective in treating depressive symptoms in those with anorexia nervosa. Treating depression in people with anorexia nervosa remains a significant clinical challenge.

Depression is estimated to affect around 50% of those with anorexia nervosa and is a poor prognostic marker for recovery – with one study demonstrating patients with comorbid depression are six times more likely to be unrecovered at a 22-year follow-up. Of those who develop anorexia, around 20-30% develop a persisting form of it, meaning that recovery is not achieved after a minimum of three years. Therefore, we can see an urgent need for novel therapeutic approaches for this particular patient group and ketamine may prove to be a viable alternative to treat depression in anorexia nervosa.

Our hope for this study is that ketamine may provide people with both anorexia and depression a treatment option that will relieve their depressive symptoms, which will in turn help them to find hope and improve their ability to engage in psychotherapy and to work towards recovery and a better quality of life. It has the potential to facilitate a “window of plasticity” which could support therapeutic efficacy, cognition and brain recovery in anorexia.

What does the EDEN study involve? 

The EDEN study is a preliminary feasibility study, where the main goal is to assess the recruitment, assessment response rate and drop-out rate as indicators of feasibility of the treatment, with secondary measures including assessing acceptability of the intervention, collecting additional outcome measures and gathering data on the safety and tolerability of oral ketamine. We conduct studies like this to help us get an early indicator of whether a larger definitive trial would be feasible and likely to show effectiveness in this population.

Selected participants will be randomly allocated to receive either ketamine, or a placebo, which they will then take twice a week across a period of four weeks, with eight dosing sessions in total. These sessions will take place at the NIHR King's Clinical Research Facility based at King's College Hospital in Camberwell.

Measurements of depression, anorexia symptoms, suicidality, and quality of life will be collected at baseline and at follow up at 28 days, three months and six months. Additionally, participants and their carers have the option to participate in semi-structured interviews and digital diaries to explore the experience of the trial and help design and optimise future studies.

The study is funded by the Medical Research Council Developmental Pathway Funding Scheme

How can people be part of the study? 

We began recruiting for the study in August 2025, primarily through Participant Identification Centres; South London & Maudsley and Central & North West London NHS Trusts. However, anyone who meets the criteria and is interested in taking part can self-refer to the study. 

Participants can receive up to £190 for taking part and can claim up to £30 per visit for travel expenses.

If you, or anyone you know, is interested in participating in the trial or would like further information, the EDEN Study Team would be more than happy to hear from you. You can get in contact with us via email: eden@kcl.ac.uk