Implicit and explicit motivational responses to high- and low-calorie food in women with disordered eating.

Eating disorders and their symptoms are thought to be associated with altered motivational responding to food. Binge eating may relate to increased reward reactivity, restrictive eating may be associated with increased threat and/or decreased reward reactivity, and the combination of these symptoms within an individual may be linked to motivational conflict to food. Using both implicit (i.e., physiological) and explicit (i.e., self-reported) measures, we tested these hypotheses in 88 women with binge eating only, restrictive eating only, both binge eating and restrictive eating, or no eating pathology. Participants viewed and rated high-calorie food, low-calorie food, and emotional images while startle eye blink and postauricular reflexes were measured. Arousal and craving, but not valence, ratings were significantly greater for high- than low-calorie food. Startle blink reflexes during all food images were significantly lower than during neutral images, whereas only high-calorie foods related to greater postauricular reactivity than neutral images. Eating pathology group did not predict implicit and explicit motivational reactions to food. Exploratory dimensional analyses revealed that rating low-calorie foods as lower on craving predicted endorsement of restrictive eating, while rating low-calorie foods as lower on valence and arousal, and experiencing lower postauricular reactivity to high-calorie foods minus neutral images, predicted greater frequency of restrictive eating episodes. Decreased implicit and explicit appetitive motivation to high- and low-calorie food may relate to the presence and frequency of restrictive eating. Future longitudinal research should investigate whether decreased appetitive responding to food is a risk factor for, versus consequence of, restrictive eating.

Tripping on nothing: placebo psychedelics and contextual factors.

RATIONALE: Is it possible to have a psychedelic experience from a placebo alone? Most psychedelic studies find few effects in the placebo control group, yet these effects may have been obscured by the study design, setting, or analysis decisions. OBJECTIVE: We examined individual variation in placebo effects in a naturalistic environment resembling a typical psychedelic party. METHODS: Thirty-three students completed a single-arm study ostensibly examining how a psychedelic drug affects creativity. The 4-h study took place in a group setting with music, paintings, coloured lights, and visual projections. Participants consumed a placebo that we described as a drug resembling psilocybin, which is found in psychedelic mushrooms. To boost expectations, confederates subtly acted out the stated effects of the drug and participants were led to believe that there was no placebo control group. The participants later completed the 5-Dimensional Altered States of Consciousness Rating Scale, which measures changes in conscious experience. RESULTS: There was considerable individual variation in the placebo effects; many participants reported no changes while others showed effects with magnitudes typically associated with moderate or high doses of psilocybin. In addition, the majority (61%) of participants verbally reported some effect of the drug. Several stated that they saw the paintings on the walls "move" or "reshape" themselves, others felt "heavy… as if gravity [had] a stronger hold", and one had a "come down" before another "wave" hit her. CONCLUSION: Understanding how context and expectations promote psychedelic-like effects, even without the drug, will help researchers to isolate drug effects and clinicians to maximise their therapeutic potential.

Associations between self-report and physiological measures of emotional reactions to food among women with disordered eating.

Individuals with eating disorders have exhibited both positive and negative emotional responses to food when assessed via self-report and psychophysiology. These mixed findings may be explained by a lack of association between self-report and physiological measures, and the degree of association may differ based on core eating disorder symptoms like dietary restriction and binge eating. Women from the community (N = 82) were recruited based on the presence or absence of dietary restriction and binge eating. We examined the startle eyeblink reflex, a physiological measure of defensive motivation, in relation to self-reported valence, arousal, and craving ratings of emotional (positive, neutral, negative) and food (high- and low-calorie) images. Dietary restriction and binge eating were investigated as moderators of self-report/physiology relationships. Replicating extant literature, valence ratings of emotional images were correlated with startle blink reflex magnitude, with more unpleasant ratings related to higher startle eyeblink reflex magnitudes. Increased craving, but not valence, ratings of food images were related to lower startle blink reflex magnitudes. Dietary restriction and binge eating did not moderate the relationship between self-report ratings and startle blink magnitude to food. Our findings suggest that self-reported appetitive motivation towards food relates to a decrease in physiologically measured aversion towards food. Future research should examine the extent to which self-report ratings correlate with physiological indices of positive emotion (e.g., postauricular reflex, zygomaticus major) during the viewing of food images in both patients with eating disorders and healthy controls.