José R. Sánchez-Martín

Social stress paradigms in male mice: Variations in behavior, stress and immunology

Male OF1 strain mice were allocated, after 2 weeks of individual housing, to cohabitating (6 or 16 days), fixed dyadic interaction pairs (6 or 16 daily encounters) or control groups (6 or 16 days). These different social stress situations were assessed for their effects on splenic contents of NE, IL-1 and IL-2 and serum levels of corticosterone. Spleen NE contents showed no significant variations, but serum corticosterone titers were generally higher in interacting pairs and subordinates. Splenic IL-2 did not respond in the same way to the treatments as IL-1. The differences in splenic interleukin contents could not be simply related to observed changes in serum corticosterone levels. Different mechanisms appear to regulate changes in glucocorticoids and the measured cytokines. These physiological phenomena do not simply reflect in the animals social status (dominant or submissive). The intensity and duration of the agonistic behavior displayed as well as the interaction experience accumulated may account for the observed differences between the paradigms.

Cognitive abilities, androgen levels, and body mass index in 5-year-old children

This study explores the potential relationship between a series of cognitive abilities and testosterone, dehydroepiandrosterone (DHEA), androstenedione, and body mass index (BMI) measurements in 5-year-old children. 60 boys and 69 girls were administered a test (K-BIT) which provided measurements of fluid intelligence (Matrices subtest), crystallized intelligence (Vocabulary subtest), and IQ composite (the combination of the two subtests); a sub-sample of 48 boys and 61 girls was also subjected to diverse tests related to theory of mind (affective labeling, appearance-reality distinction, display rules, and false belief). Testosterone, DHEA, and androstenedione levels were measured using an enzyme immunoassay technique in saliva samples. An analysis of variance failed to reveal any significant differences between boys and girls in any of the cognitive abilities assessed. The correlation analysis revealed a positive relationship between fluid intelligence and testosterone levels in boys, a negative relationship between crystallized intelligence and androstenedione levels in girls, and between affective labeling and androstenedione levels in boys. A multiple regression analysis indicated that androstenedione and BMI were the best predictors for some of the cognitive abilities assessed.

Social cognitive predictors of peer acceptance at age 5 and the moderating effects of gender

In this study we examined the effects of social intelligence, empathy, verbal ability and appearance-reality distinction on the level of peer acceptance, as well as the moderating role of gender. Participants were 98 five-year-old children (43 boys and 55 girls; mean age 5 years 3 months for boys and girls). Our results showed a main effect of social intelligence on peer acceptance, as well as several other effects that were moderated by gender: a significant and positive effect of verbal ability on social acceptance was found for boys; appearance-reality distinction was found to have a positive effect on social acceptance in the case of girls; and although empathy had a significant positive effect on social acceptance for both boys and girls, this effect was more pronounced among boys. Our results suggest that abilities promoting peer acceptance are different for boys and girls.

Aggression, dominance, and affiliation: Their relationships with androgen levels and intelligence in 5-year-old children

This study explores the potential relationship between social behavior (aggression, dominance, and affiliation) and testosterone, androstenedione, and DHEA measurements in 5-year-old children while also analyzing the moderating effect of IQ on the hormone-behavior relationship. 129 healthy normal Iberian children (60 boys and 69 girls) were videotaped in free play interactions in the school playground. Their behavior was then evaluated with particular emphasis on aggression, government, and affiliation. Testosterone, androstenedione, and DHEA levels were measured using an enzyme immunoassay technique in saliva samples. A test (K-BIT) which provides an IQ measurement for children was also administered to subjects. The correlation analysis revealed a positive relationship between the behavioral factor of Provocation and androstenedione in boys, and a regression analysis indicated that this relationship was moderated in a positive direction by the subjects intelligence. In girls, we observed a positive relationship between testosterone and Affectivity, with this relationship being moderated in a negative direction by intelligence.

Social behavior, cortisol, and sIgA levels in preschool children

OBJECTIVE This study aims to explore the possible existence of behavioral states in early stages of development, which are associated with specific cortisol production profiles and consequently with changes in the immune response [secreted immunoglobulin A (sIgA)]. METHODS The subjects were 27 boys and 21 girls of preschool age whose behavior was videotaped in free play interactions. Their behavior was then evaluated using an ethogram of the social behavior of the child. Cortisol levels were measured using a radioimmunoassay in saliva samples, and sIgA levels were measured by means of an ELISA, also in saliva samples. RESULTS No correlation between cortisol and sIgA levels was found. Variance analysis revealed that the only behavioral pattern, which showed significant differences with regard to cortisol levels, was isolation. CONCLUSIONS There seems to be a connection between cortisol levels and isolation behavior; we found no relation between high cortisol levels and a lower sIgA secretion.

Relations between aggressive behavior, immune activity, and disease susceptibility

Psychoneuroimmunology has sought to analyze the effects of stress on the immune function and the way in which emotional states and other psychological processes influence the immune response. Agonistic interactions may be considered a special form of psychological stress: social stress, thereby constituting a natural stress model that may be useful for studying the effects of this phenomenon on the immune system. The majority of studies in this area were carried out with mammals, mainly rodents. In general, results have shown a reduction in diverse humoral response measurements in submissive subjects and indicated that stress produced by agonistic interaction also results in the decrease of diverse cellular immune parameters, although this inhibitory effect is not global. In short, despite the diversity of paradigms used and the existence of some contradictory results, it may be concluded that low social ranking, submissive social status, or subjection to threat or attack behavior is linked to a state of immunodepression. As regards the influence of this type of social stress on disease susceptibility, some studies indicate that submissive subjects have a lower resistance to tumoral development and viral infections, although not all studies have obtained consistent results in this area.

Developmental trajectories of aggressive behavior in children from ages 8 to 10: The role of sex and hormones.

This study explored the developmental trajectory of aggressive behavior from age 8 to age 10 in school‐aged children, taking into account possible sex differences, as well as the involvement of certain hormones.

Parenting styles and hormone levels as predictors of physical and indirect aggression in boys and girls

This study examines the relationship between parenting style, androgen levels, and measures of physical and indirect aggression. Peer ratings of aggression were obtained from 159 eight-year-old children (89 boys and 70 girls). Parenting styles (authoritative, authoritarian or permissive) were assessed using the Parenting Styles and Dimensions Questionnaire (PSDQ).Saliva samples were obtained from children and assayed for testosterone and androstenedione concentrations. A regression analysis revealed that high testosterone levels were associated with a higher level of physical aggression in boys with authoritarian mothers. Testosterone was also found to moderate the relationship between fathers authoritarian parenting and physical aggression in girls, with both moderate and high levels being significant. In relation to indirect aggression, moderate and high levels of testosterone were associated with higher levels of this type of aggression in girls with permissive mothers. Our results highlight the importance of taking into account the interaction of biological and psychosocial variables when investigating aggressive behavior.

Factors associated with cortisol levels and health in 5–6-year-old children

This study assesses the relationships between social context (family and inter‐peer context), stress, and illness in 5–6‐year‐old children.

Daycare Center Attendance Buffers the Effects of Maternal Authoritarian Parenting Style on Physical Aggression in Children

A maternal authoritarian style has been related to the development of physical aggression during childhood and later future social problems; however, not too many studies have detected other than individual or family factors that may buffer this maternal effect. This work examines whether daycare center attendance may moderate the relationships between a mother authoritarian style and physical aggression. The study sample was 72 (40 girls) kindergarten children from Spain. Parents were asked to complete two questionnaires focused on individual family characteristics and parenting styles. At age 5, children physical aggression was assessed by direct observation at playtime; aggression scores at 6 was obtained by a peer-rated questionnaire. A least squared multiple regression was performed after controlling for children’s level of physical aggression at 5, child sex and siblings. A positive contribution of maternal authoritarian style on physical aggression was detected. Daycare center attendance appears to attenuate the effect of the mother’s authoritarian style on physical aggression, only in boys.