Processing of food stimuli in anorexia nervosa: An ERP-study comparing adolescents and adults.

Background: Anorexia nervosa (AN) is associated with altered processing of disorder-relevant stimuli. Event-related potentials (ERP) - such as the Late Positive Potential (LPP) - give information about the underlying mechanisms of central nervous stimulus processing.

Methods: Patients with AN (22 adolescents, 23 adults) and healthy controls (HCs; 17 adolescents, 24 adults) were included. Neutral, low, and high calorie food-images were rated for valence and arousal; EEG activity was recorded and LPPs (early: 350-700 ms; late: 800-1200 ms) were extracted. Effects of patient status, age group, and stimulus category were analyzed via mixed 2 × 2 × 3-AN(C)OVAs.

Results: Patients with AN rated high calorie stimuli lower in valence and higher in arousal than HCs. Controlling for hunger, food stimuli elicited higher early LPPs than neutral ones in patients and HCs. For the late LPP, patients with AN showed larger amplitudes.

Conclusion: Results suggest a highly automatic attentional bias towards low-calorie foods. Patients with AN seem to have more intense cognitive processing independent of stimulus material. More research is needed to validate and clarify differences between early and late LPP measures as well as the operationalization and relevance of hunger status.