Food Addiction and Bulimia Nervosa: New Data Based on the Yale Food Addiction Scale 2.0

Previous research on ‘food addiction’ as measured with the Yale Food Addiction Scale (YFAS) showed a large overlap between addiction‐like eating and bulimia nervosa. Most recently, a revised version of the YFAS has been developed according to the changes made in the diagnostic criteria for substance use disorder in the Diagnostic and Statistical Manual of Mental Disorders fifth edition. The current study examined prevalence and correlates of the YFAS2.0 in individuals with bulimia (n = 115) and controls (n = 341). Ninety‐six per cent of participants with bulimia and 14% of controls received a YFAS2.0 diagnosis. A higher number of YFAS2.0 symptoms was associated with lower interoceptive awareness, higher depressiveness, and higher impulsivity in both groups. However, a higher number of YFAS2.0 symptoms was associated with higher body mass and weight suppression in controls only and not in participants with bulimia. The current study is the first to show a large overlap between bulimia and ‘food addiction’ as measured with the YFAS2.0, replicating and extending findings from studies, which used the previous version of the YFAS. Compensatory weight control behaviours in individuals with bulimia likely alleviate the association between addiction‐like eating and higher body mass. Thus, the large overlap between bulimia and ‘food addiction’ should be taken into consideration when examining the role of addiction‐like eating in weight gain and obesity. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association.     

Preserved calibration of persistence based on delay‐timing distribution during sleep deprivation

We frequently encounter decisions where we have to determine whether to wait for a certain reward delayed for an uncertain duration or to move on. The appropriate decision depends upon the underlying temporal distribution of the delay. With some distributions it is best to be completely persistent, whereas in others it is more appropriate to abandon waiting after a certain period of time. The current study examined whether the ability to form temporal expectations and adjust persistence accordingly is compromised by sleep deprivation. Participants performed a willingness‐to‐wait task either in a well‐rested state or after a night of total sleep deprivation. Participants had to decide either to wait for a larger reward or to abandon waiting in favour of a smaller immediate reward. Delays were drawn from either a uniform distribution, where being persistent yields maximal returns, or from a heavy‐tailed distribution, where occasional long delays render full persistence suboptimal. In spite of increased sleepiness and decreased vigilance, sleep‐deprived participants were able to adjust waiting time appropriate to the experienced timing distribution. Additionally, sleep deprivation did not affect the foreperiod effect, indicating intact perception of conditional probability of temporal events and ability to adjust preparation accordingly.     

Right prefrontal and ventral striatum interactions underlying impulsive choice and impulsive responding

Although a multifaceted concept, many forms of impulsivity may originate from interactions between prefrontally‐mediated cognitive control mechanisms and limbic, reward or incentive salience approach processes. We describe a novel task that combines reward and control processes to probe this putative interaction. The task involves elements of the monetary incentive delay task (Knutson et al., [2000]: Neuroimage 12:20–27) and the Go/No‐Go task (Garavan et al., [1999]: Neuroimage 17:1820–1829) and requires human subjects to make fast responses to targets for financial reward but to occasionally inhibit responding when a NoGo signal rather than a target is presented. In elucidating the dynamic between reward anticipation and control we observed that successful inhibitions on monetary trials, relative to unsuccessful inhibitions, were associated, during the anticipation phase, with increased activation in the right inferior frontal gyrus (rIFG), decreased activity in the ventral striatum (VS), and altered functional connectivity between the two. Notably, this rIFG area had a small overlap but was largely distinct from an adjacent rIFG region that was active for the subsequent motor response inhibitions. Combined, the results suggest a role for adjacent regions of the rIFG in impulsive choice and in impulsive responding and identify a functional coupling between the rIFG and the VS. Hum Brain Mapp, 36:187–198, 2015. © 2014 Wiley Periodicals, Inc .     

Low Dopamine D2/D3 Receptor Availability is Associated with Steep Discounting of Delayed Rewards in Methamphetamine Dependence

Background:

Individuals with substance use disorders typically exhibit a predilection toward instant gratification with apparent disregard for the future consequences of their actions. Indirect evidence suggests that low dopamine D₂-type receptor availability in the striatum contributes to the propensity of these individuals to sacrifice long-term goals for short-term gain; however, this possibility has not been tested directly. We investigated whether striatal D₂/D₃ receptor availability is negatively correlated with the preference for smaller, more immediate rewards over larger, delayed alternatives among research participants who met DSM-IV criteria for methamphetamine (MA) dependence.

Methods:

Fifty-four adults (n = 27 each: MA-dependent, non-user controls) completed the Kirby Monetary Choice Questionnaire, and underwent positron emission tomography scanning with [¹⁸F]fallypride.

Results:

MA users displayed steeper temporal discounting (p = 0.030) and lower striatal D₂/D₃ receptor availability (p < 0.0005) than controls. Discount rate was negatively correlated with striatal D₂/D₃ receptor availability, with the relationship reaching statistical significance in the combined sample (r = -0.291, p = 0.016) and among MA users alone (r = -0.342, p = 0.041), but not among controls alone (r = -0.179, p = 0.185); the slopes did not differ significantly between MA users and controls (p = 0.5).

Conclusions:

These results provide the first direct evidence of a link between deficient D₂/D₃ receptor availability and steep temporal discounting. This finding fits with reports that low striatal D₂/D₃ receptor availability is associated with a higher risk of relapse among stimulant users, and may help to explain why some individuals choose to continue using drugs despite knowledge of their eventual negative consequences. Future research directions and therapeutic implications are discussed.     

Delinquency and drug use among adolescents and emerging adults: The role of aggression,impulsivity, empathy,and cognitive distortions

Risk behaviors are well known to be higher in adolescents and emerging adults. Drug use and delinquency present several common predictive factors. The aim of the present study was to assess the contribution of individual factors (aggression, impulsivity, empathy, and cognitive distortions) to delinquent behaviors, alcohol use and cannabis consumption among adolescents and emerging adults. Participants were between 15 and 25 years of age (M = 18.64 years, SD = 2.61); 325 were adolescents (15–18 years of age, M = 16.56, SD = 1.11, 56.31% of women) and 283 were emerging adults (19–25 years, M = 21.03, SD = 1.62, 50.88% of women). They completed self-report validated questionnaires. Multiple regression analyses showed that all individual factors significantly predicted delinquency. Impulsivity and empathy significantly predicted alcohol use. Concerning cannabis use, impulsivity is the only significantly associated predictor. Moderation analysis showed that specific associations were stronger in adolescents, whereas others were stronger in emerging adults. All these variables explained 69% of the variance of delinquency, 31% of the variance of alcohol use, and 18% of the variance of cannabis use. This model demonstrated acceptable goodness-of-fit criteria. These results may have implications for prevention and intervention.