A functional MRI study on how oxytocin affects decision making in social dilemmas: Cooperate as long as it pays off, aggress only when you think you can win.

We investigate if the neuropeptide oxytocin (OT), known to moderate social behaviour, influences strategic decision making in social dilemmas by facilitating the integration of incentives and social cues. Participants (N=29) played two economic games with different incentive structures in the fMRI scanner after receiving OT or placebo (following a double blind, within-subject design). Pictures of angry or neutral faces (the social cues) were displayed alongside the game matrices. Consistent with a priori hypotheses based on the modulatory role of OT in mesolimbic dopaminergic brain regions, the results indicate that, compared to placebo, OT significantly increases the activation of the nucleus accumbens during an assurance (coordination) game that rewards mutual cooperation. This increases appetitive motivation so that cooperative behaviour is facilitated for risk averse individuals. OT also significantly attenuates the amygdala, thereby reducing the orienting response to social cues. The corresponding change in behaviour is only apparent in the chicken (or anti-coordination) game, where aggression is incentivized but fatal if the partner also aggresses. Because of this ambiguity, decision making can be improved by additional information, and OT steers decisions in the chicken game in accordance with the valence of the facial cue: aggress when face is neutral; retreat when it is angry. Through its combined influence on amygdala and nucleus accumbens, OT improves the selection of a cooperative or aggressive strategy in function of the best match between the incentives of the game and the social cues present in the decision environment.

Trust as commodity: social value orientation affects the neural substrates of learning to cooperate.

Individuals differ in their motives and strategies to cooperate in social dilemmas. These differences are reflected by an individual's social value orientation: proselfs are strategic and motivated to maximize self-interest, while prosocials are more trusting and value fairness. We hypothesize that when deciding whether or not to cooperate with a random member of a defined group, proselfs, more than prosocials, adapt their decisions based on past experiences: they 'learn' instrumentally to form a base-line expectation of reciprocity. We conducted an fMRI experiment where participants (19 proselfs and 19 prosocials) played 120 sequential prisoner's dilemmas against randomly selected, anonymous and returning partners who cooperated 60% of the time. Results indicate that cooperation levels increased over time, but that the rate of learning was steeper for proselfs than for prosocials. At the neural level, caudate and precuneus activation were more pronounced for proselfs relative to prosocials, indicating a stronger reliance on instrumental learning and self-referencing to update their trust in the cooperative strategy.

Use of neuraminidase inhibitors in primary health care during pandemic and seasonal influenza between 2009 and 2013.

BACKGROUND: In a context of controversy about influenza antiviral treatments, this study assessed primary health-care physicians' prescription of neuraminidase inhibitors (NIs) in France during pandemic and seasonal influenza between 2009 and 2013. METHODS: This observational study, using data recorded in three national databases, estimated the rate of NI prescription among influenza-like illness (ILI) patients seen in GP and paediatrician consultations, and determined factors associated with this prescription according to a multivariate analysis. NI delivery by pharmacists was also evaluated. RESULTS: Rates of NI prescription were estimated to be 61.1% among ILI patients with a severe influenza risk factor seen in GP consultation during the A(H1N1)pdm2009 pandemic versus an average rate of 25.9% during the three following seasonal influenza epidemics. Factors associated with NI prescription were a chronic disease in patients under 65 years (OR 14.85; 95% CI 13.00, 16.97) and in those aged 65 and older (OR 7.54; 5.86, 9.70), an age ≥65 years in patients without chronic disease (OR 1.35; 1.04, 1.74), a pregnancy (OR 10.63; 7.67, 15.76), obesity (OR 4.67; 3.50, 6.22) and a consultation during the pandemic A(H1N1)pdm2009 (OR 3.19; 2.93, 3.48). The number of antiviral treatments delivered by pharmacists during the A(H1N1)pdm2009 pandemic was 835 per 100,000 inhabitants, and an average of 275 per 100,000 inhabitants during the three following seasonal influenza epidemics. CONCLUSIONS: Although physicians seem to follow the recommended indications for NIs in primary health-care practice, this study confirms the low rate of NI prescription to ILI patients with a severe influenza risk factor, especially during seasonal epidemics.

Oxytocin does not make a face appear more trustworthy but improves the accuracy of trustworthiness judgments.

Previous research on the relation between oxytocin and trustworthiness evaluations has yielded inconsistent results. The current study reports an experiment using artificial faces which allows manipulating the dimension of trustworthiness without changing factors like emotions or face symmetry. We investigate whether (1) oxytocin increases the average trustworthiness evaluation of faces (level effect), and/or whether (2) oxytocin improves the discriminatory ability of trustworthiness perception so that people become more accurate in distinguishing faces that vary along a gradient of trustworthiness. In a double blind oxytocin/placebo experiment (N=106) participants conducted two judgement tasks. First they evaluated the trustworthiness of a series of pictures of artificially generated faces, neutral in the trustworthiness dimension. Next they compared neutral faces with artificially generated faces that were manipulated to vary in trustworthiness. The results indicate that oxytocin (relative to a placebo) does not affect the evaluation of trustworthiness in the first task. However, in the second task, misclassification of untrustworthy faces as trustworthy occurred significantly less in the oxytocin group. Furthermore, oxytocin improved the discriminatory ability of untrustworthy, but not trustworthy faces. We conclude that oxytocin does not increase trustworthiness judgments on average, but that it helps people to more accurately recognize an untrustworthy face.

A method to assess seasonality of urinary tract infections based on medication sales and google trends.

BACKGROUND: Despite the fact that urinary tract infection (UTI) is a very frequent disease, little is known about its seasonality in the community. METHODS AND FINDINGS: To estimate seasonality of UTI using multiple time series constructed with available proxies of UTI. Eight time series based on two databases were used: sales of urinary antibacterial medications reported by a panel of pharmacy stores in France between 2000 and 2012, and search trends on the Google search engine for UTI-related terms between 2004 and 2012 in France, Germany, Italy, the USA, China, Australia and Brazil. Differences between summers and winters were statistically assessed with the Mann-Whitney test. We evaluated seasonality by applying the Harmonics Product Spectrum on Fast Fourier Transform. Seven time series out of eight displayed a significant increase in medication sales or web searches in the summer compared to the winter, ranging from 8% to 20%. The eight time series displayed a periodicity of one year. Annual increases were seen in the summer for UTI drug sales in France and Google searches in France, the USA, Germany, Italy, and China. Increases occurred in the austral summer for Google searches in Brazil and Australia. CONCLUSIONS: An annual seasonality of UTIs was evidenced in seven different countries, with peaks during the summer.

Estimating the excess of inappropriate prescriptions of anti-dopaminergic anti-emetics during acute gastroenteritis epidemics in France.

PURPOSE: Anti-dopaminergic anti-emetics (ADA) use for the treatment of nausea associated with gastroenteritis (GE) can be considered inappropriate, as their effects are not supported by evidence of clinical efficacy and can potentially induce serious adverse events. OBJECTIVE: This study quantifies the suboptimal consumption of ADA attributable to seasonal GE epidemics in France and its cost. METHODS: GE epidemiological data were collected and transmitted by the general practitioners (GPs) of Sentinelles network. Epidemic periods were identified by periodic regression. Drug sales data were obtained from pharmacies, and costs data were obtained from the French National Social Security. The ADA use and costs incurred by seasonal GE epidemics were calculated. RESULTS: During the epidemic periods considered in this study, the median age of patients seen by GPs for GE was 24 years old. During each epidemic, a sale increase by 14% for domperidone, by 15% for metoclopramide and 30% for metopimazine was observed. The average cost attributable to seasonal GE epidemic was 5,030,000 Euros, of which 2,160,000 Euros were incurred by the French National Social Security. CONCLUSION: Linking epidemiological databases helped to identify and quantify inappropriate ADA prescriptions. GE treatment guidelines should be disseminated more widely.

The Chikungunya epidemic on La Réunion Island in 2005-2006: a cost-of-illness study.

BACKGROUND: This study was conducted to assess the impact of chikungunya on health costs during the epidemic that occurred on La Réunion in 2005-2006. METHODOLOGY/PRINCIPAL FINDINGS: From data collected from health agencies, the additional costs incurred by chikungunya in terms of consultations, drug consumption and absence from work were determined by a comparison with the expected costs outside the epidemic period. The cost of hospitalization was estimated from data provided by the national hospitalization database for short-term care by considering all hospital stays in which the ICD-10 code A92.0 appeared. A cost-of-illness study was conducted from the perspective of the third-party payer. Direct medical costs per outpatient and inpatient case were evaluated. The costs were estimated in Euros at 2006 values. Additional reimbursements for consultations with general practitioners and drugs were estimated as € 12.4 million (range: € 7.7 million-€ 17.1 million) and € 5 million (€ 1.9 million-€ 8.1 million), respectively, while the cost of hospitalization for chikungunya was estimated to be € 8.5 million (€ 5.8 million-€ 8.7 million). Productivity costs were estimated as € 17.4 million (€ 6 million-€ 28.9 million). The medical cost of the chikungunya epidemic was estimated as € 43.9 million, 60% due to direct medical costs and 40% to indirect costs (€ 26.5 million and € 17.4 million, respectively). The direct medical cost was assessed as € 90 for each outpatient and € 2,000 for each inpatient. CONCLUSIONS/SIGNIFICANCE: The medical management of chikungunya during the epidemic on La Réunion Island was associated with an important economic burden. The estimated cost of the reported disease can be used to evaluate the cost/efficacy and cost/benefit ratios for prevention and control programmes of emerging arboviruses.

A method for selecting and monitoring medication sales for surveillance of gastroenteritis.

PURPOSE: Monitoring appropriate categories of medication sales can provide early warning of certain disease outbreaks. This paper presents a methodology for choosing and monitoring medication sales relevant for the surveillance of gastroenteritis and assesses the operational characteristics of the selected medications for early warning. METHODS: Acute diarrhoea incidences in mainland France were obtained from the Sentinelles network surveillance system for the period 2000-2009. Medication sales grouped by therapeutic classes were obtained on the same period. Hierarchical clustering was used to select therapeutic classes correlating with disease incidence over the period. Alert thresholds were defined for the selected therapeutic classes. Single and multiple voter algorithms were investigated for outbreak detection based on sales crossing the thresholds. Sensitivity and specificity were calculated respective to known outbreaks periods. RESULTS: Four therapeutic classes were found to cluster with acute diarrhoea incidence. The therapeutic class other antiemetic and antinauseants had the best sensitivity (100%) and timeliness (1.625 weeks before official alerts), for a false alarm rate of 5%. Multiple voter algorithm was the most efficient with the rule: 'Emit an outbreak alert when at least three therapeutic classes are over their threshold' (sensitivity 100%, specificity 95%, timeliness 1.750 weeks before official alerts). CONCLUSIONS: The presented method allowed selection of relevant therapeutic classes for surveillance of a specific condition. Multiple voter algorithm based on several therapeutic classes performed slightly better than the best therapeutic class alone, while improving robustness against abrupt changes occurring in a single therapeutic class.

Medication sales and syndromic surveillance, France.

Although syndromic surveillance systems using nonclinical data have been implemented in the United States, the approach has yet to be tested in France. We present the results of the first model based on drug sales that detects the onset of influenza season and forecasts its trend. Using weekly lagged sales of a selected set of medications, we forecast influenzalike illness (ILI) incidence at the national and regional level for 3 epidemic seasons (2000-01, 2001-02, and 2002-03) and validate the model with real-time updating on the fourth (2003-04). For national forecasts 1-3 weeks ahead, the correlation between observed ILI incidence and forecast was 0.85-0.96, an improvement over the current surveillance method in France. Our findings indicate that drug sales are a useful additional tool to syndromic surveillance, a complementary and independent source of information, and a potential improvement for early warning systems for both epidemic and pandemic planning.