The critical role of cognitive-based trait differences in transcranial direct current stimulation (tDCS) suppression of food craving and eating in frank obesity

Abstract

Obesity remains a major public health concern and novel treatments are needed. Transcranial direct current stimulation (tDCS) is a neuromodulation technique shown to reduce food craving and consumption, especially when targeting the dorsolateral prefrontal cortex (DLPFC) with a right anode/left cathode electrode montage. Despite the implications to treat frank (non-bingeeating) obesity, no study has tested the right anode/left cathode montage in this population. Additionally, most tDCS appetite studies have not controlled for differences in traits under DLPFC control that may influence how well one responds to tDCS. Hence, N = 18 (10F/8M) adults with frank obesity completed the Dutch Eating Behavior Questionnaire-Restraint and Barratt Impulsiveness Scale, and received 20 min of 2 mA active tDCS and control tDCS session. Craving and eating was assessed at both sessions with a food photo "wanting" test and in-lab measures of total, preferred, and less-preferred kilocalories consumed of three highly palatable snack foods. While main effects of tDCS vs. control were not found, significant differences emerged when trait scores were controlled. tDCS reduced food craving in females with lower attention-type impulsiveness (p = 0.047), reduced preferred-food consumption in males with lower intent to restrict calories (p = 0.024), and reduced total food consumption in males with higher non-planning-type impulsiveness (p = 0.009) compared to control tDCS. This is the first study to find significant reductions in food craving and consumption in a sample with frank obesity using the most popular tDCS montage in appetite studies. The results also highlight the cognitive-based heterogeneity of individuals with obesity and the importance of considering these differences when evaluating the efficacy of DLPFC-targeted tDCS in future studies aimed at treating obesity.

Keywords: Cognitive control; Dieting; Dorsolateral prefrontal cortex; Impulsiveness; Neuromodulation; Sex differences; Treatment.

Conflict of interest statement

Conflicts of interest

None.

Copyright © 2017 Elsevier Ltd. All rights reserved.

Figures

Fig. 1

Flow diagram of the participant selection process. *Self-reported height and weight and survey for DSM-5 BED criteria (American Psychiatric Association, 2013) (via research survey for Intro to Psych students and phone interview for flyer recruits).

Fig. 2

The effect of tDCS to suppress food craving for mixed foods is greater in females (N = 10) with lower Barratt Impulsiveness Scale (BIS) Attentional scores. Attentional scores × stimulation condition interaction, p = 0.047; R2 = 0.41.

Fig. 3

The effect of tDCS to suppress preferred food consumption is greater in males (N = 8) with lower Dutch Eating Behavior Questionnaire-Restraint (DEBQ-R) Intent scores. Intent scores × stimulation condition interaction, p = 0.024; R2 = 0.600.

Fig. 4

The effect of tDCS to suppress total food consumption is greater in males (N = 8) with higher Barratt Impulsiveness Scale (BIS) Nonplanning scores. Nonplanning scores × stimulation condition interaction, p = 0.009; R2 = 0.71.