Validation d'une version abrégée du TCI (TCI-56) sur un échantillon de jeunes fumeurs et non-fumeurs

Introduction: The psychobiological seven-factor model proposed by Cloninger et al. (1993) takes into account temperament and character dimensions to describe personality. Four of the dimensions are linked with biological, genetic and neuroanatomic structures, whereas the three other dimensions are related to the degree of individual, social and spiritual development. A study conducted by Wills et al. (1994) with adolescents showed that substance abuse was associated with high scores on Novelty Seeking and low scores on Harm Avoidance and Reward Dependence. The aim of the present study was, firstly, to create a short form of Cloninger's (1993) Temperament and Character Inventory (TCI) and, secondly, to study the impact of nicotine dependence as well as demographic variables on a sample of young adults. Method: We created a short form of the TCI containing 56 items (TCI-56), 8 for each scale. Responses are made on a five-point Likert type scale. A Swiss sample (n=211), of 116 women and 95 men, aged from 15 to 30 years, participated in this study. Our population was divided into a group of 81 smokers and another of 130 non-smokers, according to their scores on the Fagerstörm test for nicotine dependence (1999). Results: The structural validation consisted of two separate factor analysis with varimax rotations, one for the temperamental items, and the other, for the character ones. The first factor analysis conducted on the items of the temperament scales allowed to extract 4 factors explaining 40.7% of the variance. The correlations between factors and scales are the following: r=.71 for Novelty Seeking, r=.69 for Persistence, r=.95 for Harm Avoidance, r=.94 for Reward Dependence. The second factor analysis conducted on the items of the character scales allowed to extract 3 factors explaining 41.5% of the variance. The correlations between factors and scales are the following: r=.94 for Self-Directedness, r=.91 for Cooperativeness and r=.99 for Self-Transcendence. The internal consistencies range from α=.65 to α=.75 for the temperament scales, and from α=.71 to α=.83 for the three character scales. Concerning, the impact of the nicotine dependence, we observed that smokers have significantly higher scores for Novelty seeking, than non-smokers (p=.01). We found no difference for Harm Avoidance and Reward Dependence. Nevertheless, smokers seem to have the tendency to score higher on Transcendence (p=.06). Moreover, people having smoked more than 100 cigarettes in their life have significantly higher scores on this scale (p.04) and the correlation between Transcendence and the Fagerstörm test is significant (r=.19). We also found gender differences: the women (N=116) obtain significantly higher scores for Harm Avoidance (p<.001), for Reward Dependence (p<.001) and for Cooperation (p=.01). We further found a significant correlation between age and Self-Directedness, r=.34. We observed no interaction between gender and smoking or age and smoking on the dimensions of the TCI-56. Discussion: The TCI short form (TCI-56) seems to be a valid and useful inventory to assess personality differences. Confirming the results of others about the relation between addiction and personality, we found that smokers have significantly higher scores for Novelty seeking, than non-smokers. But we were not able to find any significant differences for Harm Avoidance and Reward Dependence. This might be due to our sample that was made of young adults. This study also shows that Transcendence could be an interesting dimension for studies on Tobacco smoking to consider. Concerning the impact of demographic variables, we observed that age and gender have specific and coherent influence on personality.

Association of candidate genes with phenotypic traits relevant to anorexia nervosa.

This analysis is a follow-up to an earlier investigation of 182 genes selected as likely candidate genetic variations conferring susceptibility to anorexia nervosa (AN). As those initial case-control results revealed no statistically significant differences in single nucleotide polymorphisms, herein, we investigate alternative phenotypes associated with AN. In 1762 females, using regression analyses, we examined the following: (i) lowest illness-related attained body mass index; (ii) age at menarche; (iii) drive for thinness; (iv) body dissatisfaction; (v) trait anxiety; (vi) concern over mistakes; and (vii) the anticipatory worry and pessimism versus uninhibited optimism subscale of the harm avoidance scale. After controlling for multiple comparisons, no statistically significant results emerged. Although results must be viewed in the context of limitations of statistical power, the approach illustrates a means of potentially identifying genetic variants conferring susceptibility to AN because less complex phenotypes associated with AN are more proximal to the genotype and may be influenced by fewer genes. Copyright © 2011 John Wiley & Sons, Ltd and Eating Disorders Association.

Absence of association between specific common variants of the obesity-related FTO gene and psychological and behavioral eating disorder phenotypes.

Extensive population-based genome-wide association studies have identified an association between the FTO gene and BMI; however, the mechanism of action is still unknown. To determine whether FTO may influence weight regulation through psychological and behavioral factors, seven single-nucleotide polymorphisms (SNPs) of the FTO gene were genotyped in 1,085 individuals with anorexia nervosa (AN) and 677 healthy weight controls from the international Price Foundation Genetic Studies of Eating Disorders. Each SNP was tested in association with eating disorder phenotypes and measures that have previously been associated with eating behavior pathology: trait anxiety, harm-avoidance, novelty seeking, impulsivity, obsessionality, compulsivity, and concern over mistakes. After appropriate correction for multiple comparisons, no significant associations between individual FTO gene SNPs and eating disorder phenotypes or related eating behavior pathology were identified in cases or controls. Thus, this study found no evidence that FTO gene variants associated with weight regulation in the general population are associated with eating disorder phenotypes in AN participants or matched controls. © 2011 Wiley-Liss, Inc.

Inbreeding avoidance through kin recognition: choosy females boost male dispersal.

Inbreeding avoidance is predicted to induce sex biases in dispersal. But which sex should disperse? In polygynous species, females pay higher costs to inbreeding and thus might be expected to disperse more, but empirical evidence consistently reveals male biases. Here, we show that theoretical expectations change drastically if females are allowed to avoid inbreeding via kin recognition. At high inbreeding loads, females should prefer immigrants over residents, thereby boosting male dispersal. At lower inbreeding loads, by contrast, inclusive fitness benefits should induce females to prefer relatives, thereby promoting male philopatry. This result points to disruptive effects of sexual selection. The inbreeding load that females are ready to accept is surprisingly high. In absence of search costs, females should prefer related partners as long as delta<r/(1+r) where r is relatedness and delta is the fecundity loss relative to an outbred mating. This amounts to fitness losses up to one-fifth for a half-sib mating and one-third for a full-sib mating, which lie in the upper range of inbreeding depression values currently reported in natural populations. The observation of active inbreeding avoidance in a polygynous species thus suggests that inbreeding depression exceeds this threshold in the species under scrutiny or that inbred matings at least partly forfeit other mating opportunities for males. Our model also shows that female choosiness should decline rapidly with search costs, stemming from, for example, reproductive delays. Species under strong time constraints on reproduction should thus be tolerant of inbreeding.

Peri-insular hemispherotomy: potential pitfalls and avoidance of complications.

Techniques for cerebral hemispherectomy have progressively evolved towards more disconnection and less excision over the last 50 years. Peri-insular hemispherotomy (PIH), as described by the senior author, has the maximal ratio of disconnection to excision among all procedures for hemispheric epilepsy. In this study, we focus on surgical complications and intraoperative anatomical observations during PIH over the last 10 years. Based on this experience, the procedure has undergone some modifications, which we detail herein.

Potential evidence of parasite avoidance in an avian malarial vector

Epidemiological studies of malaria or other vector-transmitted diseases often consider vectors as passive actors in the complex life cycle of the parasites, assuming that vector populations are homogeneous and vertebrate hosts are equally susceptible to being infected during their lifetime. However, some studies based on both human and rodent malaria systems found that mosquito vectors preferentially selected infected vertebrate hosts. This subject has been scarcely investigated in avian malaria models and even less in wild animals using natural host-parasite associations. We investigated whether the malaria infection status of wild great tits, Parus major, played a role in host selection by the mosquito vector Culex pipiens. Pairs of infected and uninfected birds were tested in a dual-choice olfactometer to assess their attractiveness to the mosquitoes. Plasmodium-infected birds attracted significantly fewer mosquitoes than the uninfected ones, which suggest that avian malaria parasites alter hosts' odours involved in vector orientation. Reaction time of the mosquitoes, that is, the time taken to select a host, and activation of mosquitoes, defined as the proportion of individuals flying towards one of the hosts, were not affected by the bird's infection status. The importance of these behavioural responses for the vector is discussed in light of recent advances in related or similar model systems.

"Iatrogenicity cascade": doing harm by treating harm?

An electronic survey on substance-induced epileptic crisis was conducted in order to investigate whether doctors, who recognise their own prescription errors, increase their therapeutic aggressiveness, resulting in a so-called "iatrogenicity cascade". Two pairs of clinical vignettes were constructed, in which a patient suffers from iatrogenic (original version) or non-iatrogenic (control version) epileptic crisis. Vignettes were randomised and sent to doctors at the University Hospital of Lausanne, Switzerland, at an interval of 3 weeks. The results of the present survey in the surveyed population of doctors suggest that inappropriate prescription does not increase therapeutic aggressiveness.

How to prevent overdiagnosis

Overdiagnosis is the diagnosis of an abnormality that is not associated with a substantial health hazard and that patients have no benefit to be aware of. It is neither a misdiagnosis (diagnostic error), nor a false positive result (positive test in the absence of a real abnormality). It mainly results from screening, use of increasingly sensitive diagnostic tests, incidental findings on routine examinations, and widening diagnostic criteria to define a condition requiring an intervention. The blurring boundaries between risk and disease, physicians' fear of missing a diagnosis and patients' need for reassurance are further causes of overdiagnosis. Overdiagnosis often implies procedures to confirm or exclude the presence of the condition and is by definition associated with useless treatments and interventions, generating harm and costs without any benefit. Overdiagnosis also diverts healthcare professionals from caring about other health issues. Preventing overdiagnosis requires increasing awareness of healthcare professionals and patients about its occurrence, the avoidance of unnecessary and untargeted diagnostic tests, and the avoidance of screening without demonstrated benefits. Furthermore, accounting systematically for the harms and benefits of screening and diagnostic tests and determining risk factor thresholds based on the expected absolute risk reduction would also help prevent overdiagnosis.

No evidence that within-group male relatedness reduces harm to females in Drosophila.

Conflict between males and females over whether, when, and how often to mate often leads to the evolution of sexually antagonistic interactions that reduce female reproductive success. Because the offspring of relatives contribute to inclusive fitness, high relatedness between rival males might be expected to reduce competition and result in the evolution of reduced harm to females. A recent study investigated this possibility in Drosophila melanogaster and concluded that groups of brothers cause less harm to females than groups of unrelated males, attributing the effect to kin selection. That study did not control for the rearing environment of males, rendering the results impossible to interpret in the context of kin selection. Here, we conducted a similar experiment while manipulating whether males developed with kin prior to being placed with females. We found no difference between related and unrelated males in the harm caused to females when males were reared separately. In contrast, when related males developed and emerged together before the experiment, female reproductive output was higher. Our results show that relatedness among males is insufficient to reduce harm to females, while a shared rearing environment - resulting in males similar to or familiar with one another - is necessary to generate this pattern.

Preventing contagion with avian influenza: Disease salience, attitudes toward foreigners, and avoidance beliefs

Building on an evolutionary approach to outgroup avoidance, this study shows relations between perceived disease salience and beliefs in the efficacy of avoiding foreigners as protective measures, in the context of a real-life pandemic risk; i.e., avian influenza. People for whom avian influenza was salient and who held unfavourable attitudes toward foreigners were more likely to believe that avoiding contact with foreigners protects against infection. This finding suggests that individual differences in social attitudes moderate evolved mechanisms relating threat of disease to outgroup avoidance.

Experimental evidence of inbreeding avoidance in the hermaphroditic snail Physa acuta

Inbreeding depression should select for inbreeding avoidance behaviours. Here we test this hypothesis in two populations of the simultaneous hermaphroditic freshwater snail Physa acuta. We recorded the copulatory behaviour of 288 pairs of sib-mates, non-kin mates from the same population, or non-kin mates from two different populations. We find that kin discriminatory behaviours exist in this species, exclusively expressed by individuals playing the female role. We discuss the relevance of our finding in the context of the evolution of recognition systems and the consequences of such a behaviour in natural populations.

Phytochrome-mediated inhibition of shade avoidance involves degradation of growth-promoting bHLH transcription factors

Plant growth and development are particularly sensitive to changes in the light environment and especially to vegetational shading. The shade-avoidance response is mainly controlled by the phytochrome photoreceptors. In Arabidopsis, recent studies have identified several related bHLH class transcription factors (PIF, for phytochrome-interacting factors) as important components in phytochrome signaling. In addition to a related bHLH domain, most of the PIFs contain an active phytochrome binding (APB) domain that mediates their interaction with light-activated phytochrome B (phyB). Here we show that PIF4 and PIF5 act early in the phytochrome signaling pathways to promote the shade-avoidance response. PIF4 and PIF5 accumulate to high levels in the dark, are selectively degraded in response to red light, and remain at high levels under shade-mimicking conditions. Degradation of these transcription factors is preceded by phosphorylation, requires the APB domain and is sensitive to inhibitors of the proteasome, suggesting that PIF4 and PIF5 are degraded upon interaction with light-activated phyB. Our data suggest that, in dense vegetation, which is rich in far-red light, shade avoidance is triggered, at least partially, as a consequence of reduced phytochrome-mediated degradation of transcription factors such as PIF4 and PIF5. Consistent with this idea, the constitutive shade-avoidance phenotype of phyB mutants partially reverts in the absence of PIF4 and PIF5