Improved planning abilities in binge eating

Abstract

Objective: The role of planning in binge eating episodes is unknown. We investigated the characteristics of planning associated with food cues in binging patients. We studied planning based on backward reasoning, reasoning that determines a sequence of actions back to front from the final outcome.

Method: A cross-sectional study was conducted with 20 healthy participants, 20 bulimia nervosa (BN), 22 restrictive (ANR) and 23 binging anorexia nervosa (ANB), without any concomitant impulsive disorder. In neutral/relaxing, binge food and stressful conditions, backward reasoning was assessed with the Race game, promotion of delayed large rewards with an intertemporal discounting task, attention with the Simon task, and repeating a dominant behavior with the Go/No-go task.

Results: BN and to a lower extent ANB patients succeeded more at the Race game in food than in neutral condition. This difference discriminated binging from non-binging participants. Backward reasoning in the food condition was associated with lower approach behavior toward food in BN patients, and higher food avoidance in ANB patients. Enhanced backward reasoning in the food condition related to preferences for delayed large rewards in BN patients. In BN and ANB patients the enhanced success rate at the Race game in the food condition was associated with higher attention paid to binge food.

Conclusion: These findings introduce a novel process underlying binges: planning based on backward reasoning is associated with binges. It likely aims to reduce craving for binge foods and extend binge refractory period in BN patients, and avoid binging in ANB patients. Shifts between these goals might explain shifts between eating disorder subtypes.

Figure 1. Race Game trial design (A), critical steps that allow the first player to systematically win if critical sticks are removed (B), and mean success rate in BN and ANB patients (red), in controls and ANR patients (blue) in neutral/relaxing, food and stress/fearful conditions (C).

Vertical bars are standard error of the mean (C).

Figure 2. Model used to investigate the association between backward reasoning in the Race Game in the food condition and approach or avoidance behaviors, under the influence of anxiety (Figure A).

Food approach behavior was determined by the shared variance of the reaction time (RT) at correct Go trials between food and neutral/relaxing conditions with neutral/relaxing data as a reference. Food avoidance behavior was determined in a similar manner, using the stressful and food conditions. Similar reasoning was carried out for “food specific” anxiety arousal and coefficient of variation of reaction time (CV-RT). Bold arrows represent reference loadings for latent variables (ellipses) and have a factor loading set to 1. Standardized coefficients are reported for Bulimia Nervosa (BN) and Anorexia Nervosa Binging subtype (ANB) patients (Figure B and supplementary table ST4 in file S2). **: p<0.05.

Figure 3. Receiver Operating Characteristic Curves (Figures A, B and C) for the difference in rate of success in the Race game between the food and neutral conditions for the detection of binging status in patients with anorexia nervosa restrictive subtype (ANR) and binging subtype (ANB) (Figure A), in patients with bulimia nervosa (BN) and healthy controls (Figure B) and in the four aforementioned groups (Figure C).

Statistic tests were one tail. Abbreviations: AUC, area under curve. CI, confidence interval.