Dronabinol in severe, enduring anorexia nervosa: a randomized controlled trial

OBJECTIVE: The evidence for pharmacological treatment of severe, longstanding anorexia nervosa (AN) is sparse and the few controlled pharmacologic studies have focused on a narrow range of drugs. The aim of the present study was to investigate the effects of treatment with a synthetic cannabinoid agonist on body weight and eating disorder-related psychopathological personality traits in women with severe, enduring AN.

METHOD: This add-on, prospective, randomized, double blind, controlled crossover study was conducted between 2008 and 2011 at a specialized care center for eating disorders. Twenty-five women over 18 years with AN of at least 5 years duration were randomized to treatment with either dronabinol-placebo or placebo-dronabinol. In addition to the standardized baseline therapeutic regime, the participants received dronabinol, 2.5 mg twice daily for 4 weeks and matching placebo for 4 weeks, separated by a 4-week wash-out period. Primary outcome was the mean change in body weight. Secondary outcome was score changes on the Eating Disorder Inventory-2 (EDI-2). Data were analyzed for the 24 patients who completed the trial.

RESULTS: During dronabinol treatment, participants gained 0.73 kg (t = 2.86, df = 22, p < 0.01) above placebo without significant psychotropic adverse events. Dronabinol significantly predicted weight gain in a multiple linear regression including EDI-2 body dissatisfaction score and leptin. EDI-2 subscale scores showed no significant changes over time.

DISCUSSION: Dronabinol therapy was well tolerated. During four weeks of exposure it induced a small but significant weight gain in the absence of severe adverse events.