Smartphone-based approach-avoidance bias modification training for anorexia nervosa - A randomized clinical trial

Effective treatments for anorexia nervosa (AN) are available, yet many patients do not respond to treatment or experience relapse. Cognitive bias modification aims to ameliorate cognitive biases that are assumed to contribute to the development and maintenance of AN. This study examines the efficacy of a novel mobile approach-avoidance bias modification training (ABMT) with food cues for AN.

In this RCT, 90 inpatients with AN received six sessions of active or sham ABMT with food cues or no training, alongside treatment-as-usual. Primary outcome was self-reported eating disorder psychopathology; secondary outcomes included food-related approach-avoidance bias, fear of food, and BMI. Outcomes were assessed at baseline, end-of-training and at 6-month follow-up.

Active ABMT did not result in greater reductions in eating disorder psychopathology. Similarly, treatment conditions did not differ regarding in change in BMI, approach-avoidance bias or fear of food, neither in the short term nor in the long term. Changes in approach-avoidance bias did not mediate training effects on any outcomes.

This first RCT on ABMT for AN found no superiority of active ABMT over sham or no ABMT in reducing eating disorder psychopathology. ABMT also appeared insufficient to alter food-related approach bias. Mobile ABMT with food cues in its current form does not seem to be an efficacious adjunct treatment to inpatient TAU for patients with AN. Further research may explore whether modified training protocols and personalized approaches are more promising in this regard.

This study's design was registered at the German Clinical Trials Register [https://trialsearch.who.int/Trial2.aspx?TrialID=DRKS00022078].