Acute subjective response to alcohol as a function of reward and punishment sensitivity

The Acquired Preparedness Model of Cannabis Use in Emerging Adulthood: Comparing Within-Person and Between-Person Effects

OBJECTIVE

The acquired preparedness model (APM) posits that high sensitivity to reward biases individuals to learn and maintain positive outcome expectancies, which in turn increase substance use, and that high sensitivity to punishment biases individuals to learn and maintain negative outcome expectancies, decreasing use. Little work has applied the APM to cannabis use, particularly with longitudinal data and methods that separate within- and between-person associations. The current study addressed these gaps.

METHOD

The sample comprised 314 emerging adults (age range: 19.13-21.39 years; 52% female; predominantly non-Hispanic White [76%] or African American [15%]) recruited using random-digit dialing. Data were taken from three annual assessments. Latent curve models with structure residuals were used to distinguish between- and within-person associations. We controlled for bidirectional associations and demographic covariates.

RESULTS

At the between-person level, high sensitivity to reward was related to high positive expectancies and high cannabis use. High positive expectancies were associated with high cannabis use. High sensitivity to punishment was related to high negative expectancies and low cannabis use. No within-person associations were supported.

CONCLUSIONS

These findings suggest a risk profile for emerging adult cannabis use involving high sensitivity to reward and positive expectancies and a protective profile involving high sensitivity to punishment and negative expectancies. However, our findings did not support the notion that the proposed learning processes unfold within individuals across annual assessments. Most notably, the findings emphasize the importance of disaggregating within- and between-person associations using a longitudinal design to better understand pathways to cannabis use in the developmental period of emerging adulthood.

Phenol-Rich Food Acceptability: The Influence of Variations in Sweetness Optima and Sensory-Liking Patterns

The consumption of phenol-rich foods is limited by their prominent bitterness and astringency. This issue has been addressed by adding sweet tastes, which suppress bitterness, but this is not a complete solution since individuals also differ in their preference for sweetness. In this study, we aimed at identifying groups of consumers differing in sweetness optima and sensory-liking patterns. To this end, increasing concentrations of sucrose were added to a chocolate pudding base. This allowed us to (1) investigate if individual differences in sensory responses are associated with different sweet liking optima in a product context, (2) define the psychological and oro-sensory profile of sweet liker phenotypes derived using a product context, and (3) assess if individuals differing in sweet liking optima differ also in consumption and liking of phenol-rich foods and beverages as a function of their sensory properties (e.g., sweeter vs. more bitter and astringent products). Individuals (1208; 58.4% women, 18–69 years) were characterised for demographics, responsiveness to 6-n-propylthiouracil (PROP), personality traits and attitudes toward foods. Three clusters were identified based on correlations between sensory responses (sweetness, bitterness and astringency) and liking of the samples: liking was positively related to sweetness and negatively to bitterness and astringency in High and Moderate Sweet Likers, and the opposite in Inverted U-Shaped. Differences between clusters were found in age, gender and personality. Furthermore, the Inverted-U Shaped cluster was found to have overall healthier food behaviours and preferences, with higher liking and consumption of phenol-rich vegetables and beverages without added sugar. These findings point out the importance of identifying the individual sensory-liking patterns in order to develop more effective strategies to promote the acceptability of healthy phenol-rich foods.

Reduced attentional capture by reward following an acute dose of alcohol

RATIONALE

Previous research has shown that physically salient and reward-related distractors can automatically capture attention and eye gaze in a visual search task, even though participants are motivated to ignore these stimuli.

OBJECTIVES

To examine whether an acute, low dose of alcohol would influence involuntary attentional capture by stimuli signalling reward.

METHODS

Participants were assigned to the alcohol or placebo group before completing a visual search task. Successful identification of the target earned either a low or high monetary reward but this reward was omitted if any eye gaze was registered on the reward-signalling distractor.

RESULTS

Participants who had consumed alcohol were significantly less likely than those in the placebo condition to have their attention captured by a distractor stimulus that signalled the availability of high reward. Analysis of saccade latencies suggested that this difference reflected a reduction in the likelihood of impulsive eye movements following alcohol.

CONCLUSIONS

Our findings suggest that alcohol intoxication reduces the capacity to attend to information in the environment that is not directly relevant to the task at hand. In the current task, this led to a performance benefit under alcohol, but in situations that require rapid responding to salient events, the effect on behaviour would be deleterious.

Relationships between generalized impulsivity and subjective stimulant and sedative responses following alcohol administration

Impulsivity and subjective response (SR) to alcohol (i.e., individual differences in sensitivity to pharmacologic alcohol effects) are both empirically supported risk factors for alcohol use disorder; however, these constructs have been infrequently studied as related risk factors. The present investigation examined a self-report measure of impulsivity (i.e., the Barratt Impulsiveness Scale, Version 11) in relation to acute alcohol effects (i.e., stimulant and sedative SR). Participants came from 2 cohorts of the Chicago Social Drinking Project. Heavy and light drinkers from Cohort 1 (n = 156) and heavy social drinkers from Cohort 2 (n = 104) were examined using identical laboratory protocols following oral alcohol administration using a within-subject, double-blind, placebo-controlled laboratory study design. Self-reported impulsivity and, for comparison purposes, sensation seeking were measured at baseline, and SR was measured once prior to and 4 times following alcohol administration. More impulsive light, but not heavy, drinkers reported heightened stimulant SR following alcohol administration. High impulsive, light drinkers reported stimulant SR at a magnitude similar to that for heavy drinkers, whereas low impulsive, light drinkers reported limited stimulant SR. The interaction between impulsivity and sensation seeking did not statistically predict stimulant SR, and overall, impulsivity was a stronger predictor than was sensation seeking. However, impulsivity was not statistically predictive of dampened sedative SR among light or heavy drinkers. These findings partially replicate and extend the recent literature linking self-reported impulsivity to heightened stimulant SR from alcohol. Future directions include longitudinal studies and research relating multiple facets of impulsivity to SR. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Influences of Psychological Traits and PROP Taster Status on Familiarity with and Choice of Phenol-Rich Foods and Beverages

Plant phenolics are powerful antioxidants and free radical scavengers that can contribute to the healthy functional properties of plant-based food and beverages. Thus, dietary behaviours rich in plant-based food and beverages are encouraged. However, it is well-known that the bitter taste and other low-appealing sensory properties that characterize vegetables and some other plant-based foods act as an innate barrier for their acceptance. The aim of this study was to investigate the influence of psychological traits and PROP status (the responsiveness to bitter taste of 6-n- propylthiouracil) on the choice of and familiarity with phenol-rich vegetables and beverages varying in recalled level of bitterness and astringency. Study 1 aimed at assessing the variations of the sensory properties of vegetable and coffee/tea items with two check-all-that-apply (CATA) questionnaires (n = 201 and n = 188 individuals, respectively). Study 2 aimed at investigating how sensitivity to punishment, to reward, and to disgust, food neophobia, private body consciousness, alexithymia, and PROP responsiveness affect choice and familiarity with phenol-rich foods (n = 1200 individuals). A Choice Index was calculated for vegetables (CV) and coffee/tea (CC) as a mean of the choices of the more bitter/astringent option of the pairs and four Familiarity Indices were computed for vegetables (FV) and coffee/tea (FC), higher (+) or lower (-) in bitterness and astringency. Subjects higher in food neophobia, sensitivity to punishment or sensitivity to disgust reported significantly lower choice indices than individuals lower in these traits, meaning that they systematically opted for the least bitter/astringent option within the pairs. Familiarity with vegetables was lower in individuals high in sensitivity to punishment, in food neophobia and in alexithymia, irrespective of their sensory properties. The Familiarity Index with coffee/tea characterized by higher bitterness and astringency was lower in individuals high in food neophobia, sensitivity to disgust, and alexithymia. No significant effect of PROP was found on any indices. The proposed approach based on product grouping according to differences in bitterness and astringency allowed the investigation of the role of individual differences in chemosensory perception and of psychological traits as modulators of phenol-rich foods preference and consumption.

Acute alcohol exposure increases tyrosine hydroxylase protein expression and dopamine synthesis in zebrafish

Zebrafish have become a popular animal model for investigating the effects of alcohol on the brain and behaviour. Acute exposure to alcohol has been shown to alter dopaminergic signalling in zebrafish, but the underlying mechanisms have not been well defined. In the current study, we characterize the effects of alcohol on the zebrafish dopaminergic system by focusing on tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. Using western blot analysis, we demonstrate that a 60min exposure to 1% alcohol increases tyrosine hydroxylase protein expression in the zebrafish brain. Enzymatic activity assays confirmed that alcohol also increases tyrosine hydroxylase enzymatic activity, whereas HPLC analysis demonstrated increased levels of whole-brain dopamine and its metabolite DOPAC. In addition to activation of the dopaminergic system, behavioural analysis revealed accompanying increase of distance traveled following 1% alcohol exposure. These findings suggest that acute alcohol exposure elevates dopamine synthesis via increased tyrosine hydroxylase protein expression. Our results support the hypothesis that alcohol alters dopaminergic signalling in the zebrafish brain in a similar manner as compared to mammals.