Explaining Fairness : Results from an Experiment in Guinea.

Fairness is undoubtedly an essential normative concept in humans and promotes cooperation in human societies. The fact that fairness exists is puzzling, however, because it works against the short-term interest of individuals. Theories of genetic evolution, cultural evolution, and gene-culture coevolution identify plausible mechanisms for the evolution of fairness in humans. Such mechanisms include kin selection, the support of group-beneficial moral norms through ethnic markers, free partner choice with equal outside options, and free partner choice with reputation as well as spite in small populations. Here, we present the results of a common-pool resource game experiment on sharing. Based on data from 37 multiethnic villages in a subsistence agricultural population in Foutah Djallon, Guinea, we show that fair behavior in our experiment increased with increasing ethnic homogeneity and market integration. Group size and kinship had the opposite effect. Overall, fair behavior was not conditional on reputation. Instead, the ability of the different village populations to support individuals' fairness in situations lacking the opportunity to build a positive reputation varied significantly. Our results suggest that evolutionary theory provides a useful framework for the analysis of fairness in humans.

Cannabis use in Switzerland 2015-2045: A population survey based model.

BACKGROUND: Alternative cannabis regulation models are discussed and implemented worldwide. A baseline scenario under the assumption of no policy or market changes may prove useful to forecast cannabis use and treatment demand and evaluate changes in legislation. METHODS: Based on data of the Continuous Rolling Survey of Addictive Behaviours and Related Risks on cannabis use, age, gender and nationality from 2011 to 2015, we used general estimating equation analysis to model lifetime and 30-days prevalence from 2015 to 2045 in Switzerland accounting for demographic trends. RESULTS: Lifetime prevalence of cannabis use is projected to grow from 28.3% (CI 95% 27.8-28.8) in 2015 to 42.0% (CI 95% 41.0-43.0) in 2045. 30-days prevalence would increase slightly from 2.70% (CI 95% 2.53-2.88) to 3.39% (CI 95% 3.11-3.66). Due to population growth, absolute numbers with past 30-day cannabis use are estimated to increase from 202,784 (CI 95% 189,534-216,035) to 314,302 (CI 95% 288,504-340,100). Among those aged under 30 years no substantial change in lifetime and 30-days prevalence of cannabis use is projected. Larger changes are estimated to occur in the age group 30+. The mean age of past 30-day cannabis users would increase for men with Swiss nationality from 30.3 to 38.7 years. DISCUSSION: Population-based survey data and demographic projections can be used to develop baseline scenarios of future cannabis use. Assuming no changes in cannabis legislation, growing absolute numbers of users will likely increase treatment demand. Cannabis use is estimated to increase among the group aged >30 years, which is currently underrepresented in clinical treatment and research. Our findings highlight the need for prospective baseline scenarios to evaluate the impact of legislative changes on cannabis use. Moreover, in Switzerland effective prevention and treatment interventions for cannabis use disorders are required even if cannabis legislation remains unchanged.

Impact of a single oral dose of 100,000 IU vitamin D3 on profiles of serum 25(OH)D3 and its metabolites 24,25(OH)2D3, 3-epi-25(OH)D3, and 1,25(OH)2D3 in adults with vitamin D insufficiency.

BACKGROUND: We investigate the effect of a high dose of vitamin D3 on circulating concentrations of 25(OH)D3 and its metabolites 24,25(OH)2D3, 3-epi-25(OH)D3, and 1,25(OH)2D3 in healthy individuals with self-perceived fatigue and vitamin D insufficiency [25(OH)D3<50 nmol/L]. METHODS: One hundred and seven study participants (age 20-50 years) were randomized to receive a single 100,000 IU dose of vitamin D3 (n=52) or placebo (n=55). Vitamin D metabolite concentrations in serum were measured before, and 4 weeks after, supplementation. RESULTS: Overall, 52% of participants receiving vitamin D3 attained a serum 25(OH)D3 level >75 nmol/L. Among individuals who received vitamin D3, there were significant increases in serum concentrations of 25(OH)D3 and its metabolites 24,25(OH)2D3, 3-epi-25(OH)D3, and 1,25(OH)2D3 at 4 weeks; however, inter-individual variability in these changes was substantial. Positive correlations between serum 25(OH)D3 and 24,25(OH)2D3 and 3-epi-25(OH)D3, and a significant negative correlation between serum 1,25(OH)2D3 and 3-epi-25(OH)D3, were found 4 weeks after supplementation. The 24,25(OH)2D3/25(OH)D3 and 24,25(OH)2D3/1,25(OH)2D3 ratios were significantly increased, compared with baseline, in participants receiving vitamin D3. Baseline 25(OH)D3 concentration was the only factor predictive of the change in 25(OH)D3 after supplementation. CONCLUSIONS: Administration of a single high dose of vitamin D3 leads to a significant increase in concentrations of 25(OH)D3, 24,25(OH)2D3, 3-epi-25(OH)D3 and 1,25(OH)2D3; induction of the catabolic pathway predominates over the production of 1,25(OH)2D3. Due to the high inter-individual variation in the 25(OH)D3 response to supplementation, any given dose of vitamin D is unlikely to achieve optimal vitamin D status in all treated individuals.

The socio-economic drivers of bushmeat consumption during the West African Ebola crisis.

Bushmeat represents an important source of animal protein for humans in tropical Africa. Unsustainable bushmeat hunting is a major threat to wildlife and its consumption is associated with an increased risk of acquiring zoonotic diseases, such as Ebola virus disease (EVD). During the recent EVD outbreak in West Africa, it is likely that human dietary behavior and local attitudes toward bushmeat consumption changed in response to the crisis, and that the rate of change depended on prevailing socio-economic conditions, including wealth and education. In this study, we therefore investigated the effects of income, education, and literacy on changes in bushmeat consumption during the crisis, as well as complementary changes in daily meal frequency, food diversity and bushmeat preference. More specifically, we tested whether wealthier households with more educated household heads decreased their consumption of bushmeat during the EVD crisis, and whether their daily meal frequency and food diversity remained constant. We used Generalized Linear Mixed Models to analyze interview data from two nationwide household surveys across Liberia. We found an overall decrease in bushmeat consumption during the crisis across all income levels. However, the rate of bushmeat consumption in high-income households decreased less than in low-income households. Daily meal frequency decreased during the crisis, and the diversity of food items and preferences for bushmeat species remained constant. Our multidisciplinary approach to study the impact of EVD can be applied to assess how other disasters affect social-ecological systems and improve our understanding and the management of future crises.

Effect of vitamin D3 on self-perceived fatigue: A double-blind randomized placebo-controlled trial.

BACKGROUND: Vitamin D deficiency is frequent and has been associated with fatigue in uncontrolled trials. METHODS: This is the first double-blind placebo-controlled clinical trial to investigate the efficacy of per os vitamin D3 (cholecalciferol) in treating fatigue among otherwise healthy persons with low serum 25-hydroxyvitamin D (25(OH)D) levels. We enrolled 120 individuals (mean age 29 ±â€Š6 years, 53% women) presenting with fatigue and vitamin D deficiency (serum 25(OH)D < 20 µg/L). Participants were randomized to a single oral dose of 100,000 units of vitamin D or placebo. The primary endpoint was intra-individual change in the fatigue assessment scale (FAS) at 4 weeks after treatment. RESULT: The mean age of the participants was 29 ±â€Š6 years, 53% were women. Mean FAS decreased significantly more in the vitamin D group (-3.3 ±â€Š5.3; 95% confidence interval [CI] for change -14.1 to 4.1) compared with placebo (-0.8 ±â€Š5.3; 95% CI for change -9.0 to 8.7); (P = 0.01). Amelioration of fatigue was reported more frequently in vitamin D than in placebo group (42 [72%] vs. 31 [50%]; P = 0.01; odds ratio [OR] 2.63, 95% CI for OR 1.23-5.62). Among all participants, improvement in fatigue score correlated with the rise in 25(OH)D level (R = -0.22, P = 0.02). CONCLUSION: Vitamin D treatment significantly improved fatigue in otherwise healthy persons with vitamin D deficiency.This study was registered at the www.ClinicalTrials.gov Protocol ID NCT02022475.

QTc prolongation in methadone maintenance--the role of HCV infection.

OBJECTIVES: Several studies have reported prolonged QTc intervals in patients under methadone maintenance treatment, including development of torsade-de-pointes arrhythmia and death. It is still not clear why some patients develop critical QTc extensions while others do not. METHODS: ECG findings in a convenience sample of 210 methadone-maintained heroin-dependent patients, taking HCV-infection status and methadone dosage into account simultaneously by means of a multiple linear regression model with QTc-interval as the dependent variable. RESULTS: Prolonged QTc-time is associated with hepatitis C infections (p = 0.005) and higher doses of racemic methadone (p = 0.012). CONCLUSION: Infection with hepatitis C increases the likelihood of critical QTc prolongation in patients in methadone maintenance treatment.

Agonist substitution--a treatment alternative for high-dose benzodiazepine-dependent patients?

There is vast evidence for the superiority of agonist treatments (methadone, buprenorphine) over a withdrawal approach in opioid-dependent populations. Little research, however, has been conducted on the same approach for the treatment of high-dose benzodiazepine (BZD) dependence. Even large-scale reviews and meta-analyses discussing treatment strategies for benzodiazepine-dependent patients focus solely upon approaches that aim at achieving abstinence, namely on complete BZD withdrawal. While the types of interventions differ (e.g. gradual benzodiazepine taper with a long or a short half-life benzodiazepine, switching to non-benzodiazepine anxiolytics or prescribing adjunctive medications such as antidepressants or anticonvulsants on an in- or out-patient basis), the common aim of treatment still is total abstinence from benzodiazepines. However, the majority of patients suffering from high-dose BZD dependence do not succeed with long-term abstinence, irrespective of the procedure, and clinicians have been using BZD 'substitution' treatment in such cases for decades. Therefore, we suggest the evaluation of a substitution approach in this group, consisting of maintenance treatment with a slow-onset, long-acting BZD. Advantages of such a procedure may be improved health, less craving, fewer withdrawal complications, reduced anxiety, increased treatment retention, improvements in social functioning and less illegal activity. Cognitive impairments, the most problematic side effects of substitution treatment with benzodiazepines, could possibly be minimized by using an optimal agonist.

The barriers to smoking cessation in Swiss methadone and buprenorphine-maintained patients.

BACKGROUND: Smoking rates in methadone-maintained patients are almost three times higher than in the general population and remain elevated and stable. Due to the various negative health effects of smoking, nicotine dependence contributes to the high mortality in this patient group. The purpose of the current study was to investigate Swiss methadone and buprenorphine-maintained patients' willingness to stop smoking and to clarify further smoking cessation procedures. METHODS: Substance abuse history, nicotine dependence, and readiness to stop smoking were assessed in a sample of 103 opiate-dependent patients in the metropolitan area of Zurich, Switzerland. Patients were asked to document their smoking patterns and readiness to quit. RESULTS: Only a small number of patients were willing to quit smoking cigarettes (10.7%) and, even though bupropione or nicotine replacement therapy was included in the fixed daily treatment care, only one patient received nicotine replacement therapy for smoking cessation. A diagnosis of depression in patients' clinical records was associated with readiness to stop smoking. No significant associations were found between readiness to quit smoking and age, methadone treatment characteristics, and presence of co-dependencies. CONCLUSION: The current prescription level of best medicine for nicotine dependence in Swiss methadone and buprenorphine-maintained patients is far from adequate. Possible explanations and treatment-relevant implications are discussed.

Association between aggressiveness, schizotypal personality traits and cannabis use in Swiss psychology students.

Associations between aggressiveness, schizotypal traits, and self-declared cannabis consumption were explored in Swiss psychology students (n = 205). Higher hostility levels were strongly associated with more pronounced schizotypal traits, whereas frequency of cannabis use was not. Therefore, earlier reported correlations might be due to a subgroup of hostile consumers.