Reconnecting through dissociation: a 5-month follow-up case study on ketamine-assisted psychotherapy for anorexia nervosa.

INTRODUCTION

Ketamine, an N-methyl-D-aspartate receptor antagonist, has demonstrated rapid antidepressant effects at sub-anesthetic doses, making it a promising candidate for treatment-resistant mood disorders, anxiety, post-traumatic stress disorder, suicidality, and recently, eating disorders (EDs). However, its effects are transient, and ketamine-assisted psychotherapy (KAP) has emerged as a method to extend therapeutic benefits by combining ketamine's heightened neuroplasticity with psychotherapy. Emerging evidence suggests KAP can reduce ED psychopathology and alleviate comorbid symptoms of depression and anxiety, potentially improving patients' engagement in psychotherapy and enhancing treatment outcomes.

CASE PRESENTATION

This study presents a 5-month follow-up of a female patient in her late twenties who underwent a structured treatment protocol consisting of four KAP sessions delivered within an Acceptance and Commitment (ACT) framework, plus three ketamine booster treatments. At intake, the patient presented with a diagnosis of anorexia nervosa (AN) and comorbid depression, reporting persistent intrusive thoughts about food and body image, dissatisfaction with prior treatments, and only partial relief from antidepressants. The patient sought ketamine treatment to improve energy levels, emotional flexibility, and overall quality of life. Assessments, including medical evaluations and self-reported measures of eating disorder pathology, depression, anxiety, suicidal ideation, quality of life, psychological flexibility, and ketamine-related side effects, were conducted at five time points both before and after the intervention. The primary aim was to investigate potential changes in ED psychopathology and comorbid symptoms follwoing treatment.

CONCLUSION

To our knowledge, this is the first documented case of structured KAP for AN showing both rapid and sustained symptom remission five months post-treatment, as well as the first European study to comprehensively investigate outcomes associated with KAP in EDs. Changes observed across most assessments indicated a consistent pattern: marked symptom reduction from baseline through the fourth KAP session, followed by a temporary symptom increase during the therapy-free interval between the final KAP session and the first ketamine booster dose. Symptoms then declined during the booster phase, with stabilization or further improvement at five-month follow-up. Ketamine was well-tolerated, with no increase in side effects or emergence of new symptoms. While preliminary findings are promising, important knowledge gaps remain. These include ketamine's applicability across ED subtypes, severity levels, and age groups, as well as optimal treatment and assessment protocols that support long-term therapeutic effects and prevent relapse.