Social anxiety and the cortisol response to social evaluation in children and adolescents.

Contradictory findings have been reported on the relation between social anxiety and the cortisol response to social evaluation in youth. The present longitudinal study aimed to clarify this relation by taking pubertal development into account. Data were collected in two waves, two years apart, for a community sample of 196 participants, aged 8-17 years at Time 1. Pubertal development and social anxiety were assessed with self-report questionnaires. Salivary cortisol was obtained before and after participants completed the Leiden Public Speaking Task. Data were analyzed using regression analysis with clustered bootstrap. The dependent variable was the cortisol area under the curve. Social anxiety and pubertal development scores were decomposed into between- and within-participants components. Between participants, the relation between social anxiety and the cortisol response to public speaking varied with pubertal development: socially anxious individuals showed higher responses at low levels of pubertal development, but lower responses at high levels of pubertal development. Within participants, an increase in social anxiety over time was associated with a lower cortisol response. The results are in line with the suggestion that the responses of socially anxious individuals change from elevated in childhood to attenuated in adolescence and adulthood. Attenuation of the cortisol response is explained by theories proposing that the stress response changes with the duration of the stressor.

Effects of adolescent sociocognitive development on the cortisol response to social evaluation.

Adolescents become increasingly sensitive to social evaluation. Some previous studies have related this change to pubertal development. The present longitudinal study examined the role of sociocognitive development. We investigated whether or not the transition to recursive thinking, the ability to think about (others') thoughts, would be associated with changes in the magnitude and timing of the cortisol response to social evaluation. Salivary cortisol was obtained during the Leiden Public Speaking Task. The task was administered twice with a 2-year interval to 221 participants, aged 9-17 years at Time 1. The area under the curve was computed to assess the magnitude of the overall cortisol response. Two difference scores, reflecting speech anticipation and speech delivery, were computed to assess the timing of the cortisol response. Recursive thinking was measured with a cartoon description task. Regression analyses with clustered bootstrap controlling for pubertal development, age, and general cognitive functioning showed that the transition to recursive thinking predicted an increase in the cortisol response to speech anticipation, but was unrelated to the magnitude of the overall cortisol response. This is in line with the view that increasing sensitivity to social evaluation in adolescence is mainly due to the effects of pubertal hormones on affective regions of the brain. Sociocognitive development affected the timing rather than the magnitude of the cortisol response. The results suggest that recursive thinking enables earlier realization of social-evaluative threat. (PsycINFO Database Record

In vitro interaction of Zajdela ascites hepatoma cells with lipid vesicles.

We studied the in vitro interaction between Zajdela ascites hepatoma cells and small unilamellar vesicles, consisting of 14C-labeled phosphatidylacholine, cholesterol, and phosphatidylserine (molar ratio 5 : 4 : 1), containing high intravesicular concentrations of carboxyfluorescein or fluorescein isothiocyanate tagged dextran. The entrapped markers were found to be associated with the cells to a lesser degree than the vesicle membrane marker. This discrepancy, which is slightly less pronounced for fluorescein isothiocyanate tagged dextran than for carboxyfluorescein, increases with incubation time and decreases with increasing vesicle lipid concentration in the incubation mixture. Vesicle-plasma membrane exchange of the vesicle lipid marker could not entirely explain the observed discrepancy. It is tentatively concluded that the gap mainly arises from a selective loss of entrapped dyes from vesicles actually interacting with the cell surface. Both spectrofluorimetry and fluorescence microscopic observations, as well as the relative insensitivity of vesicle uptake towards the presence of metabolic inhibitors, exclude a major contribution of endocytosis as a vesicle uptake route. We therefore conclude that vesicles are primarily internalized by a vesicle-cell fusion-like process. The observed discrepancy in uptake between entrapped materials and vesicle lipid is discussed in terms of a two-site vesicle-cell surface interaction model.

Two-year stability of individual differences in (para)sympathetic and HPA-axis responses to public speaking in childhood and adolescence.

Long-term stability of individual differences in stress responses has repeatedly been demonstrated in adults, but few studies have investigated the development of stability in adolescence. The present study was the first to investigate the stability of individual differences in heart rate, parasympathetic (RMSSD, pNN50, HF), sympathetic (LF/HF, SC), and HPA-axis (salivary cortisol) responses in a youth sample (8-19 years). Responses to public speaking were measured twice over 2 years. Stability was moderate for absolute responses and task delta responses of HR, RMSSD, pNN50, and HF. Stability was lower for SC and task delta responses of LF/HF and cortisol. Anticipation delta responses showed low stability for HR and cortisol. The latter was moderated by age or puberty, so that individual differences were more stable in more mature individuals. The results support the suggestion that stress responses may be reset during adolescence, but only for the HPA axis.

Age and puberty differences in stress responses during a public speaking task: do adolescents grow more sensitive to social evaluation?

During adolescence pubertal development is said to lead to an increase in general stress sensitivity which might create a vulnerability for the emergence of psychopathology during this period. However, the empirical evidence for increasing stress sensitivity is scarce and mixed. Biological responses (salivary cortisol and alpha-amylase) were investigated during a social-evaluative stressor, the Leiden Public Speaking Task, in 295 nine to 17-year olds. Specific attention was paid to different elements of the task, that is anticipation to and delivery of the speech. Biological reactivity to the speech task increased with age and puberty, particularly during anticipation. Current findings support the idea that biological stress sensitivity increases during adolescence, at least in response to a social-evaluative situation. The increasing stress sensitivity appears related to both age and pubertal maturation, but unique contribution could not be distinguished. The importance of measuring anticipation is discussed.

A prepared speech in front of a pre-recorded audience: subjective, physiological, and neuroendocrine responses to the Leiden Public Speaking Task.

This study describes a new public speaking protocol for youth. The main question asked whether a speech prepared at home and given in front of a pre-recorded audience creates a condition of social-evaluative threat. Findings showed that, on average, this task elicits a moderate stress response in a community sample of 83 12- to 15-year-old adolescents. During the speech, participants reported feeling more nervous and having higher heart rate and sweatiness of the hands than at baseline or recovery. Likewise, physiological (heart rate and skin conductance) and neuroendocrine (cortisol) activity were higher during the speech than at baseline or recovery. Additionally, an anticipation effect was observed: baseline levels were higher than recovery levels for most variables. Taking the anticipation and speech response together, a substantial cortisol response was observed for 55% of participants. The findings indicate that the Leiden Public Speaking Task might be particularly suited to investigate individual differences in sensitivity to social-evaluative situations.