Ketamine as adjuvant treatment in eating disorders: an exploratory study of a case series and retrospective analysis

Eating disorders (EDs) significantly impair physical health and psychosocial functioning. Few effective therapeutic approaches exist for EDs, particularly in Anorexia Nervosa (AN). The use of ketamine, already characterized as a noncompetitive NMDA antagonist anesthetic in depression and suicidal ideations, could be an innovative adjuvant treatment for the AN spectrum.

We describe a case series of eight patients treated with intravenous Ketamine Adjuvant Treatment (KAT) combined with usual care. We also review the literature and discuss the theoretical mechanisms behind the influence of KAT in EDs. Our patients were all female, with a diagnosis of AN spectrum, and aged between 16 and 44. We offered KAT attempting to remodel rigid food-centered thoughts. Some sessions were guided by psychomotor or psychological support, thus working on self-image, body perceptions, self-esteem, and sensorial re-exposure to "forbidden" food.

KAT significantly improved BMI, with a coefficient of 0.71 (0.23-1.20, p = 0.002), with a tendency to improve weight regain dynamics from the fourth or fifth infusion onwards. It could also reduce AN psychopathology and obsessive-compulsive-like symptoms (ruminations, cognitive rigidity, guilt), improving clinical evolution.

Our findings underscore the potential of KAT as a therapeutic approach for restrictive EDs as an adjuvant treatment or after failure of first-line treatments. It particularly addresses rigid thought patterns and neurocognitive biases that are notoriously difficult to target. Ketamine's "pro-plasticity" and "pro-neurogenesis" properties may facilitate this effect. KAT represents a potential tool after failure of first-line treatments. Future research in controlled studies is imperative to corroborate its effect.