Sucrose Bingeing Reduces the Reward Value of Sucrose

Binge eating occurs primarily on highly palatable food (PF) suggesting that the reward value of food has an important role in this behaviour. Bingeing also leads to reward dysfunction in rats and humans. The rewarding effect of binge eating may involve opioid mechanisms as opioid antagonists reduce PF consumption in animals that binge eat and binge eating produces neuroadaptations of opioid receptors in rodents. We tested this hypothesis by using the conditioned place preference (CPP) paradigm. First we established a sucrose CPP in male and female Long-Evans rats (n=8 for each group) using 1%, 5%, 15%, or 30% sucrose solution. Next, rats underwent the sucrose bingeing model in which separate groups of rats (n=8 for each group) received 12hr and 24hr access to 10% sucrose solution and chow, 12hr access to 0.1% saccharin solution and chow, or 12hr access to chow only every day for 28 days. Immediately following these sessions, rats were conditioned and tested in the CPP paradigm using a 15% sucrose solution. Finally, we examined whether the sucrose bingeing model altered morphine reward in female rats. Rats (n=8 for each group) received 12hr and 24hr access to 10% sucrose solution and chow every day for 28 days. Immediately following this access period, rats were conditioned to morphine (6mL/kg) or saline solution in the CPP paradigm and tested for a CPP. In all experiments, rats drank more sucrose solution than water during conditioning sessions. Male rats did not develop a CPP to any concentration of sucrose solution and females developed a CPP to 15% sucrose solution only. Following the sucrose bingeing protocol, sucrose CPP was attenuated in male rats that binged on sucrose and in all female rats. Sucrose bingeing in females did not affect the development of a CPP to morphine. These results suggest that sucrose consumption and sucrose CPP are measures of different psychological components of reward. Furthermore, sucrose bingeing reduces the rewarding effect of sucrose, but not morphine, suggesting that opioid reward is still intact.

Identifying the key sociocultural influences on drinking behavior in high and moderate binge-drinking countries and the public policy implications

Despite considerable state investment and initiatives, binge drinking is still a major behavioral problem for policy makers and communities in many parts of the world. Furthermore, the practice of bingeing on alcohol seems to be spreading to young people in countries traditionally considered to have moderate drinking behaviors. Using a sociocultural lens and a framework of sociocultural themes from previous literature to develop propositions from their empirical study, the authors examine binge-drinking attitudes and behaviors among young people from high and moderate binge-drinking countries. The authors then make proposals regarding how policy makers can use social marketing more effectively to contribute to behavior change. Qualitative interviews were conducted with 91 respondents from 22 countries who were studying in two high binge-drinking countries at the time. The results show support for three contrasting sociocultural propositions that identify influences on binge drinking across these countries.

A longitudinal study of body change strategies among adolescent males

This study was designed to examine the factors predicting a range of body change strategies among adolescent males over an 8-month time period. This is the first published longitudinal study of body change strategies to increase weight and muscles among males. The 5 body change strategies in the present study were eating and exercise to lose weight, increase weight, increase muscles, bingeing, and use of food supplements. The extent to which Body Mass Index (BMI) and these body change strategies predicted each other over an 8-month period was evaluated. The role of pressure from parents and peers to lose weight, increase weight, or increase muscles was also evaluated. After controlling for the Time 1 level of each variable, only bingeing, and use of food supplements were predicted by other Time 1 body change variables. Bingeing at Time 1, and a combination of all of the other variables predicted bingeing at Time 2; use of food supplements and bingeing at Time 1 predicted the use of food supplements at Time 2. Perceived pressure from parents and peers to lose weight at Time 1 predicted strategies to lose weight at Time 2; perceived pressure from parents and peers to increase weight at Time 1 predicted strategies to increase weight at Time 2; and perceived pressure to lose weight, increase weight, and increase muscles at Time 1 predicted the use of food supplements at Time 2. These results indicate that extreme body change strategies are predicted by the adoption of more normative body change strategies at an earlier point in time, and that a range of body change strategies among adolescent males are affected by perceived pressures from parents and peers.

Reinforcement sensitivity theory (RST) and body change behaviour in males

According to the unrevised Reinforcement Sensitivity Theory two motivational systems shape personality: a behavioural approach system (BAS) that determines sensitivity to rewards, and a behavioural inhibition system (BIS) that determines sensitivity to punishments. The role of reinforcement sensitivity in body change behaviour in males was explored with a non-clinical sample of 120 men aged 18–40 years. Self-reported symptoms of unhealthy weight loss (weight preoccupation, fasting, bingeing/purging) and body development (muscle/size preoccupation, obligatory exercise, use of chemical supplements) were regressed on measures of BAS and BIS sensitivity. Significant relationships were observed between BAS sensitivity and body development, and between BIS sensitivity and weight loss. These relationships were mediated by internalization of the athletic/muscular ideal, body comparisons, the importance of achieving one’s ideal or ‘best possible’ body (in the case of BAS but not BIS), and body dissatisfaction (in the case of BIS but not BAS). These results support the proposition that body development in males is influenced by sensitivity to rewards associated with achieving a certain body shape, and that weight loss is influenced by sensitivity to punishments associated with possessing an unsatisfactory body shape.

Acculturation, body image, and eating behaviours in Muslim-Australian women

The relationship between western acculturation, body dissatisfaction, and eating behaviours was examined in a sample of 101 Muslim-Australian women between 18 and 44 years of age (M=27.3, SD=7.5). A questionnaire was completed containing measures of cultural identification (heritage and mainstream), body dissatisfaction and disordered eating (dietary control, bingeing and purging), internalization of the thin ideal, and self-esteem. A series of path analyses identified significant positive relationships between mainstream identification and the measures of body dissatisfaction and disordered eating that were mediated by thin-ideal internalization. Path analyses also identified significant negative relationships between heritage identification and the measures of body dissatisfaction and disordered eating that were mediated by self-esteem. These results are indicative of the potential risks to body image incurred by women who adopt Western values, and of the benefits in retaining heritage cultural values that promote a positive self image.

Association between 5-HTTLPR genotypes and persisting patterns of anxiety and alcohol use : results from a 10-year longitudinal study of adolescent mental health

The serotonin transporter gene (5-HTT) encodes a transmembrane protein that plays an important role in regulating serotonergic neurotransmission and related aspects of mood and behaviour. The short allele of a 44 bp insertion/deletion polymorphism (S-allele) within the promoter region of the 5-HTT gene (5-HTTLPR) confers lower transcriptional activity relative to the long allele (L-allele) and may act to modify the risk of serotonin-mediated outcomes such as anxiety and substance use behaviours. The purpose of this study was to determine whether (or not) 5-HTTLPR genotypes moderate known associations between attachment style and adolescent anxiety and alcohol use outcomes. Participants were drawn from an eight-wave study of the mental and behavioural health of a cohort of young Australians followed from 14 to 24 years of age (Victorian Adolescent Health Cohort Study, 1992 - present). No association was observed within low-risk attachment settings. However, within risk settings for heightened anxiety (ie, insecurely attached young people), the odds of persisting ruminative anxiety (worry) decreased with each additional copy of the S-allele (B30% per allele: OR 0.77, 95% CI 0.62–0.97, P¼0.029). Within risk settings for binge drinking (ie, securely attached young people), the odds of reporting persisting high-dose alcohol consumption (bingeing) decreased with each additional copy of the S-allele (B35% per allele: OR 0.74, 95% CI 0.64–0.86, Po0.001). Our data suggest that the S-allele is likely to be important in psychosocial development, particularly in those settings that increase risk of anxiety and alcohol use problems.

Eating disorders in children and adolescents: an update

Purpose of review Children and adolescents with eating disorders frequently present to child mental health and paediatric services and have significant morbidity, psychosocial impairment and mortality. Efforts to treat these individuals have been hampered by a poor evidence base for effective interventions. This article reviews research published during 2004 with a primary focus on this challenging clinical area. Recent findings Research published during 2004 has replicated past epidemiological findings and expanded our understanding of the relationship of family meal structure and disordered eating. Research has provided assistance in the well known clinical conundrums of excessive exercising in anorexia nervosa and predicting when return of menses will occur. There has also been clarification of adolescent bingeing. Potential advances include a new, noninvasive method of measuring body composition and investigations in adolescents on leptin, neuro and gastrointestinal peptides. Importantly, further evidence of the effectiveness of family therapy for anorexia nervosa and short-term benefits from intervention programs have been published. Summary The research base that will influence clinical practice in child and adolescent eating disorders is increasing. More research is required in all areas of intervention.

Use of latent profile analysis to identify eating disorder phenotypes in an adult Australian twin cohort

Context: The relationships among the different eating disorders that exist in the community are poorly understood, especially for residual disorders in which bingeing or purging occurs in the absence of other behaviors. Objective: To examine a community sample for the number of mutually exclusive weight and eating profiles. Design: Data regarding lifetime eating disorder symptoms and weight range were submitted to a latent profile analysis. Profiles were compared regarding personality, current eating and weight, retrospectively reported life events, and lifetime depressive psychopathology. Setting: Longitudinal study among female twins from the Australian Twin Registry in whom eating was assessed by a telephone interview. Participants: A community sample of 1002 twins (individuals) who had participated in earlier waves of data collection. Main Outcome Measures: Number and clinical character of latent profiles. Results: The best fit was a 5-profile solution with women who were (1) of normal weight with few lifetime eating disorders (4.3%), (2) overweight (10.6% had a lifetime eating disorder), (3) underweight and generally had no eating disorders except for 5.3% who had restricting anorexia nervosa, (4) of low to normal weight (89.0% had a lifetime eating disorder), and (5) obese (37.0% had a lifetime eating disorder). Each profile contained more than 1 type of lifetime eating disorder except for the third profile. Women in the first and third profiles had the best functioning, with women in the fourth and fifth profiles having similarly poorer functioning. The women in the fourth group had a symptom profile distinctive from the other 4 groups in terms of severity; they were also more likely to have had lifetime major depression and suicidality. Conclusion: Lifetime weight ranges and the severity of eating disorder symptoms affected clustering more than the type of eating disorder symptom.

Étude des liens entre la consommation ponctuelle abusive de cocaïne injectée et les facteurs associés à la transmission du VIH

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Étude des liens entre la consommation ponctuelle abusive de cocaïne injectée et les facteurs associés à la transmission du VIH

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.