The role of impulsivity and binge eating in outpatients with overweight or obesity: an EEG temporal discounting study

BackgroundBinge eating (BE) is associated with a range of cognitive control deficits related to impulsivity, including lower response inhibition, preference for immediate gratification, and maladaptive decision-making. The aim was to investigate whether impulsivity and BE may interact with the decision process and underlying brain activity in outpatients with overweight or obesity who are starting a treatment to achieve weight loss.MethodsA sample of 26 treatment-seeking outpatients with overweight or obesity was evaluated for impulsivity, BE, and temporal discounting rates. Impulsivity was measured with the Barratt Impulsiveness Scale (BIS-11), according to which two groups were composed: high BIS and low BIS; BE was assessed with the eating disorders module of the Structured Clinical Interview for DSM5-Research Version, according to which two groups were composed: with (BE group) or without BE (NBE group). Changes in subjective value of rewards were measured with the Temporal Discounting Task (TDt) where participants had to choice between sooner but smaller vs. later but larger monetary rewards. These choices were made in two differently delayed conditions ("Now" and "Not-now"). Brain rhythms were recorded through high-density electroencephalogram (hd-EEG) during the TDt.ResultsPatients with BE reported more impulsive tendencies and perceived sooner rewards as more gratifying when both options were delayed (Not-now condition, p = 0.02). The reward choice in the TDt was accompanied by a general EEG alpha band desynchronization in parietal areas observed without differences between experimental conditions and patients groups. No effects were observed within the Now condition or in the other EEG bands.ConclusionsThe tendency to favor immediate rewards may constitute an obstacle to adhering to treatment plans and achieving weight loss goals for outpatients with overweight or obesity. Clinicians are therefore encouraged to include psychological factors, such as impulsivity and dysfunctional eating behaviors, when designing weight loss programs. By addressing these psychological aspects, clinicians can better support patients in overcoming barriers to adherence and achieving sustainable weight loss.Trial registrationThis study was approved by the Ethics Committee of the Department of Psychological, Health, and Territorial Sciences of the University G. d'Annunzio of Chieti-Pescara (Prot. n. 254 of 03/14/2017).Although the health risk of overweight and obesity is widely acknowledged, weight loss treatments are often unsuccessful in the long term due to several factors. Binge eating (BE) might explain some of the reduced benefits from the treatments. In this study, we investigated whether impulsivity and BE may interact decision processes among outpatients with overweight or obesity, and we looked at their underlying brain activity. Patients with BE tended to be more impulsive and to prefer sooner rewards compared to later ones. In all patients, alpha oscillations in the parietal lobe have been observed to play a dominant role during reward choice processes. A preference for immediate rewards might help to explain the low long-term success of weight loss treatment plans. The study may also provide useful information for clinicians working with patients with overweight or obesity.