Temperamental Change in Adolescence and Its Predictive Role on Anxious Symptomatology.

Growing evidence supports the hypothesis that temperamental traits are not static throughout adolescence. The known links between both reactive and regulatory temperament and anxiety symptoms should be investigated bearing this hypothesis in mind. This study collected self-reported data on behavioral inhibition system (BIS) sensitivity, attentional control (AC), and anxiety symptomatology, from 296 adolescents (64.2% girls; M = 12.96 years at the first assessment, SD = 0.47) every six months, four times over eighteen months. The relationships between temperament factors (AC and BIS sensitivity), considered longitudinally (by means of their trajectories) and anxiety symptoms were investigated using Multigroup Latent Growth Modeling (MLGM), as well as the mediating effect of sex on trajectories and anxiety. BIS sensitivity decreased over time and showed differential patterns across sexes. AC remained relatively stable and we found no sex influence on its trajectory. On the other hand, we observed that the BIS sensitivity trajectory was a significant predictor of anxiety symptomatology at age 15. In conclusion, temperamental changes between the ages of 13 and 15 seem to play a relevant role in explaining subsequent anxiety symptomatology, under the mediating influence of sex.

Diminished complexity of heart rate time series in adolescents facing negative events during everyday life / Complejidad reducida de las series temporales de frecuencia cardíaca en adolescentes afrontando eventos negativos diarios

Physiological systems need to be flexible in order to adapt to a changing environment. Negative events, however, induce flexibility reductions thatseem necessary for coping purposes. To date, studies have measured linear variability and entropy in heart output, but none have examined thescaling properties of the cardiac system when individuals deal with stressful everyday events. This study was aimed at testing the hypothesis thatthe complexity of the cardiac dynamics is diminished when individuals face negative events in real life. Cardiac variability (linear) and complexity(nonlinear), as well as discomfort and effectiveness of event-related emotion regulation (EER) were ecologically examined in N = 65 adolescents(Mage = 14.80 years; SDage = 0.86; 55.38% girls). Repeated Measures MANOVAs revealed higher heart rate (HR) and lower cardiac complexity(higher long-term scaling exponent, p = .029; lower Fractal Dimension FD, p = .030; and lower Sample Entropy, p = .001) during EER in comparisonwith non-emotion regulation conditions (NER). Wilcoxon non-parametric tests revealed higher Hurst exponents (p = .006) in EER than in NER. Nosignificant correlations were found between discomfort and cardiac variables although the higher the cardiac entropy in NER conditions, the greaterthe self-rated effectiveness of EER (p < .050). EER processes involved increases in HR as well as scaling and FD changes that might reflect thereal-time scale’s predominance in HR output when adolescents are dealing with negative events.(AU)

Los sistemas fisiológicos necesitan ser flexibles para adaptarse a un entorno cambiante. Sin embargo, los eventos negativos disminuyen dicha flexibilidad que parecenecesaria para lograr un afrontamiento exitoso. Hasta entonces, los estudios han medido la variabilidad lineal y la entropía de la frecuencia cardíaca(FC), pero ninguno ha examinado las propiedades de escala del sistema cardíaco cuando se afrontan acontecimientos estresantes diarios. Esteestudio investigó si la complejidad cardíaca disminuye cuando los individuos se enfrentan a eventos negativos cotidianos. La variabilidad cardíaca(lineal) y la complejidad (no lineal), así como el malestar y la eficacia de los episodios de regulación emocional (EER) se examinaron ecológica-mente en N = 65 adolescentes (Medad = 14,80; DEedad = 0,86; 55,38% chicas). Los MANOVA de medidas repetidas revelaron una mayor FC y unamenor complejidad cardíaca (mayor exponente de escala a largo plazo, p = .029; menor dimensión fractal DF, p = .030; y menor entropía muestral,p = .001) durante los EER en comparación con las condiciones de no regulación emocional (NER). Las pruebas de Wilcoxon revelaron mayoresexponentes de Hurst (p = .006) en EER que en NER. No hubo correlaciones significativas entre el malestar y las variables cardíacas, pero a mayorentropía cardíaca en NER, mayor eficacia autocalificada en EER (p < .050). Los EER implicaron aumentos en la FC, así como cambios en la escalay en la DF que podrían reflejar el predominio de la escala en tiempo real del sistema cardíaco cuando los adolescentes afrontan eventos negativos.(AU)

Decrements in Adolescent Cardiac Complexity During Mother-Adolescent Conflicts.

The present study aimed to provide further evidence on the usefulness of non-linear cardiac measures when examining the output of the cardiac system. Scale-invariant self-similarity and entropy, in addition to heart rate variability (HRV) given by time- and frequency-domain measures were calculated in a sample of N = 55 healthy adolescents (Mage = 14.122, SDage = 0.698) during 10-min positive (non-stressful) and negative (stressful) interactions with their mothers. We also explored sex influence in adolescents' cardiac output using both HRV measures and non-linear cardiac measures. Repeated measures MANOVA revealed a marginal within-group effect for HRV measures, F(3,51) = 2.438, p = 0.075, η2p = 0.125), and a significant within-group effect for non-linear cardiac measures, F(6, 48) = 3.296, p = 0.009, η2p = 0.292, showing a significant decrement in adolescents' cardiac complexity during the negative interaction. No significant effect for sex was found in either non-linear cardiac measures or HRV measures, but results suggest lower cardiac scaling in females than in males. These findings suggest a real-time scale predominance in heart rate output when adolescents face an aversive situation and support the importance of non-linear cardiac measures to gain insight into the cardiac system and its regulatory mechanisms. Further research is needed to examine sex-differences in cardiac complexity during aversive situations.

Adolescents' Positive Cognitive Emotion Regulation Predicts Heart Trajectories During a Mother-Adolescent Conflict Interaction.

This paper aimed to (a) validate a novel technique that quantifies the length of the trajectories the cardiac system follows within a two-dimensional state-space, and (b) test its usefulness to better understand how cognitive emotion regulation (CER) style is associated with cardiac output. A positive CER style was assessed in a sample of healthy adolescents (n = 57), and mean and total distances, in addition to heart rate variability (HRV) measures and cardiac entropy (SampEn), were calculated during a conflict discussion with the adolescents' mothers. Associations between distances and HRV measures in time and frequency-domains and SampEn were examined to better understand the physiological meaning of distances; further, whether a positive CER style would predict distances, HRV, and SampEn. Correlation analysis revealed that associations of distances with time-domain HRV measures were stronger than associations with frequency-domain HRV measures, while correlations between distances and SampEn were moderate. Hierarchical multiple regression analysis revealed that a positive CER style predicted distances and SampEn, but not HRV measures. Distances are clearly time-domain measures of HRV, but only partly capture the complexity of the heart signal. The results highlight the importance of assessing heart rate dynamics beyond HRV in the study of CER.

Adolescents at risk of anxiety in interaction with their fathers: Studying non-verbal and physiological synchrony.

Adolescence is a vulnerable period in terms of the onset of anxiety disorders, and dyadic parent-adolescent interactions may play a key role in either increasing or reducing the risk of psychopathologies. This study examines the presence of physiological synchrony (specifically, linkage in interbeat interval series) and non-verbal synchrony in positive and negative interactions between adolescents (aged 13-16) and their fathers. Non-verbal synchrony was quantified through the coordination of the interactants' body movements, using an automated video-analysis algorithm (motion energy analysis). Participants were made up of 53 parent-adolescent dyads, the latter at either low (n = 28) or high (n = 25) risk of anxiety. Adolescents at low risk of anxiety displayed statistically significant levels of non-verbal synchrony with their fathers during positive interactions. Non-verbal synchrony was not found in the father-adolescent dyads featuring adolescents at high risk of anxiety. Physiological synchrony was not significantly present above chance level in either of the groups of adolescents. Overall, the results suggest that adolescents at high risk of anxiety may have difficulties in managing non-distressing interactions with their fathers. The results also suggest that physiological synchrony is not a straightforward phenomenon.

Effects of a transdiagnostic cognitive behaviour therapy-based programme on the natural course of anxiety symptoms in adolescence.

BACKGROUND: Anxiety disorders frequently have an onset during adolescence, which when left untreated could lead to a chronic course and outcome. This study aimed to examine the way in which a cognitive behaviour therapy-based programme (Super Skills for Life - adolescent version; SSL-A) could change the course of anxiety symptoms through adolescent's behavioural performance and cardiac function. METHOD: Sixty-one adolescents at risk of developing an anxiety disorder (45.30% boys; M = 13.76 years, SD = 0.32) were randomly assigned to either an intervention (IG), placebo (PG), or a waitlist group (WG). Adolescents in the IG participated in SSL-A over an 8-week period. Adolescents in the PG participated in an 8-session school-work programme. Adolescents in the WG did not receive any intervention. Anxiety symptoms were assessed every six months, twice before the intervention, as well as at the post-intervention and six months after the intervention. Participants in the IG additionally underwent a stressful task to assess behavioural performance and cardiac adjustment. RESULTS: Adolescents in the IG significantly reported lower levels of social phobia and generalised anxiety symptoms at the follow-up assessment compared to the adolescents in the PG and the WG. They also showed a significant improvement in vocal quality and lower discomfort during a stressful task at post-intervention, and showed attenuated cardiac recovery indexes, in terms of sample entropy. LIMITATIONS: The study has a small sample size. CONCLUSION: SSL-A changed the natural course of anxiety symptoms, as shown by a significant reduction in social phobia and generalised anxiety symptoms, and a significant improvement in behaviour and physiological (cardiac) function during a stressful situation.

Differences in Autonomic Flexibility in Adolescents with Distinct Emotion Regulation Styles during Acute Stress.

An inverted U-shaped pattern in heart rate (HR) and a U-shaped pattern in heart rate variability (HRV) are easily recognizable when individuals experience any acute stressor. How cardiac complexity (scaling and entropy) changes under acute stress is not well known. Psychologically, emotion regulation (ER) style is likely to influence the individual's specific behavioral response when affronting stress. This study tested whether adolescents with distinct ER styles would show different patterns of linear and nonlinear cardiac changes under stressful conditions. We predicted less autonomic flexibility for adolescents with a highly negative emotional regulation (HNER) style (n = 10) than for those adolescents with a highly positive emotional regulation (HPER) style (n=10). Further, associations between linear and nonlinear measures during each condition were examined for each group. Repeated measures ANOVAs revealed that HR and HRV changed according to the predicted pattern. Higuchi's fractal dimension and Sample Entropy followed a U-shaped pattern, whereas the short-term scaling exponent followed the reverse pattern. Cardiac changes across conditions were larger in the HPER group. Significant associations between linear and nonlinear measures were found in the HPER group but not in the HNER group. Results are cautiously discussed within a multiscale framework of fluctuations of the different cardiac features.

Anxiety in Early Adolescence: Heterogeneous Developmental Trajectories, Associations with Risk Factors and Depressive Symptoms.

This study aimed: (1) to identify heterogeneous trajectories of anxiety symptoms in early adolescence; (2) to analyze the relationships between risk factors and identified trajectories; (3) to study the association between anxiety symptom trajectories and depression symptom course. Anxiety and depressive symptoms of 825 participants (44.40% boys; mean initial age = 13.01, SD = 0.56) was assessed every 6 months over an 18-month period. Trajectory identification relied on latent-variable approach. As a result, 2-4 trajectories were identified for social phobia (SP), generalized anxiety (GA) and panic symptoms, revealing at least a low-symptom course and a trajectory of elevated symptoms (at-risk trajectory). Being girl and sibling cohabitation were related to at-risk trajectories, and a course of low effortful control and heightened negative affectivity. Finally, SP and GA symptoms were related to heightened depressive symptom courses. Relevant implications towards tailored prevention and intervention are highlighted to promote a healthy development across adolescence.

Sex differences in adolescents' cardiac reactivity and recovery under acute stress: The importance of nonlinear measures.

How well adolescents can self-regulate in the face of stressors has considerable implications for long-term well-being and risk of psychopathology. This study investigated sex differences in adolescents' cardiac reactivity and recovery during a stressful task. Measures of cardiac variability (linear) and complexity (nonlinear) were obtained from N = 92 adolescents, 41 males (M age = 13.28, SD = 0.69; BMI = 21.9) and 51 females (M age = 13.36, SD = 0.67; BMI = 21.5). The adolescents underwent the Trier Social Stress Test, consisting of five conditions: baseline, anticipation, social exposure, math task, and recovery. Repeated measures ANOVAs revealed that female in comparison to male adolescents showed lower cardiac complexity revealed by higher short-term scaling exponent at baseline (p = .006) and math (p = .013) and lower entropy at exposure (p = .013) and math (p = .012). A marginal between-groups effect was found for Higuchi's fractal dimension, F(1, 90) = 3.67, p = .059, ηp2  = .041, with females showing lower fractal dimension than males in math (p = .037). Linear measures did not reveal sex-related differences. Results suggest that adolescent females show lower cardiac complexity during stress. These findings support the importance of nonlinear cardiac measures for understanding cardiac reactivity during stress. Further research is needed to test the hypothesis that cardiac complexity is useful to detect an increased risk of emotional disorders, disorders that are more prevalent in women.

How Far has Your Heart Travelled? Examining Heart System Trajectories in State Space.

This paper introduces a new measure to evaluate heart output from a dynamical systems approach. The measure is based on the time delay technique for two-dimensional state space reconstruction from time series of interbeat intervals. The system's trajectories within this space are depicted and the mean distance, as well as the total and maximum distances travelled by the system, are calculated in pixels. Preliminary data from adolescents with highly positive emotional regulation (HPER) style (n=10) and adolescents with highly negative (HNER) style (n=10) who underwent a protocol of stress induction show the usefulness of the new metrics to distinguish the dynamical behavior of the heart systems from these groups. Repeated measures ANOVAs revealed that changes in all three distances across conditions (baseline, anticipation of stress, exposure to stress, and recovery) were significant in the HPER group but not in the HNER group. As to the physiological meaning of the new measure a correlational analysis revealed that associations with time-domain HRV measures were stronger than associations with frequency-domain HRV measures in both groups. Because of the small sample size, bootstrap resampling was used to obtain confidence intervals. Distances calculated with the new measure are sensitive to the ER-related cardiac flexibility under acute stress conditions. However, the physiological meaning of the new indices remains unclear.

Reactive Heart Rate Variability and Cardiac Entropy in Children with Internalizing Disorder and Healthy Controls.

Atypical vagal reactivity has been linked to internalizing psychopathology and less adaptive emotion regulation, but reactive cardiac entropy is largely unexplored. Therefore, this study investigated reactive vagally-mediated heart-rate variability (vmHRV) and cardiac entropy in relation to emotion regulation. Electrocardiograms of 32 children (9-13 years) with internalizing difficulties and 25 healthy controls were recorded during a baseline and a sad film. Reactivity-measures were calculated from the root mean square of successive differences (RMSSD) and sample entropy (SampEn). Emotion regulation was assessed using the emotion regulation checklist (ERC). Determinants of reactive SampEn and RMSSD were analyzed with marginal and generalized linear models. The study also modeled the relationship between cardiac reactivity and emotion regulation while controlling for psychopathology. The two groups differed significantly in vmHRV-reactivity, with seemingly higher vagal-withdrawal in the control group. SampEn increased significantly during the film, but less in subjects with higher psychopathology. Higher reactive entropy was a significant predictor of better emotion regulation as measured by the ERC. Internalizing subjects and controls showed significantly different vmHRV-reactivity. Higher reactive cardiac entropy was associated with lower internalizing psychopathology and better emotion regulation and may reflect on organizational features of the neurovisceral system relevant for adaptive emotion regulation.

Negative cognitive emotion regulation as a predictor of adolescent heart rate variability and entropy under social stress.

BACKGROUND AND OBJECTIVES: Negative cognitive emotion regulation (ER) strategies are particularly important within the framework of anxiety problems amongst youths and how they cope with stressful events. The aim of this study was to examine the associations between both negative and positive ER style and cardiac regulation under stressful conditions. DESIGN: Eighty-nine adolescents (M = 13.31 years, SD = 0.68, 44.94% girls) were exposed to a socially relevant stress induction protocol. METHODS: Participants' emotion regulation strategies were assessed and their cardiac function was recorded. RESULTS: A negative ER style predicted heart rate (HR) entropy at the stressful stage after controlling for anxiety scores. In addition, heart rate variability reactivity and recovery and HR entropy recovery were larger (p < .05) in the low negative ER style group (n = 16) than in the high negative ER style group (n = 23). CONCLUSIONS: Results suggest that individuals with a highly negative ER style have diminished autonomic flexibility.

Assessing adolescents' internalizing symptoms using virtual social networks: A format equivalence study of the Revised Child Anxiety and Depression Scale / Evaluación de la sintomatología interiorizada en adolescentes mediante redes sociales: un estudio de equivalencia de formatos de la "Escala revisada de ansiedad y depresión infantil"

The widespread use of virtual social networks (VSN) by adolescents makes it possible to conduct psychological assessments or health promotion using these platforms. However, psychometric properties of them should be validated. This study aimed to test the feasibility of administering the Revised Child Anxiety and Depression Scale (RCADS) over a secure social network, while preserving its original psychometric properties. To do so, a sample of 703 adolescents (M= 13.86 years, SD= 0.49) completed the questionnaire either over a social network or using paper and pencil. We tested a two-way format equivalence: quantitative equivalence (comparing score distributions across versions); and qualitative or conceptual equivalence (comparing the between-factor correlations between versions and measurement invariance). As a result, no difference was found between the score distributions of the two versions and between-factor intercorrelations with similar patterns in both versions. Finally, both methods for administering the RCADS showed an adequate fit with their theoretical latent structure, thus preserving format equivalence. To sum up, VSN may, therefore, constitute appropriate contexts for conducting psychological assessment and research among adolescents

El uso de las redes sociales por parte de adolescentes está bastante extendido actualmente. Esto posibilita el desarrollo de programas de evaluación y promoción de la salud mediante dichas vías, si se conservan garantías psicométricas en su uso. Este estudio pretendía comprobar si la "Escala revisada de ansiedad y depresión infantil" (RCADS) mantenía sus propiedades psicométricas originales cuando era aplicado mediante una red social. Una muestra de 703 adolescentes (M= 13,86 años; DT= 0,49) completaron la escala en formato tradicional o en una red social. Se evaluaron dos tipos de equivalencia entre formatos: equivalencia cuantitativa (distribución de las puntuaciones entre formatos) y cualitativa o conceptual (patrones de intercorrelaciones e invarianza de medida entre formatos). No se encontraron diferencias de las escalas en el formato tradicional y en una red social. Además, el patrón de intercorrelaciones entre factores fue similar y se observó invarianza de medida entre formatos. En conclusión, la versión en red social de la RCADS mostró propiedades psicométricas equivalentes a la tradicional, destacándose la aplicabilidad en estas plataformas

Altered Heart Rate Regulation in Adolescent Girls and the Vulnerability for Internalizing Disorders.

Background: The association between decreased heart rate variability (HRV) and increased internalizing symptoms is well documented. Adolescence is a critical period for the development of mental health problems, in particular internalizing symptoms. Previous research has illustrated sex differences in adolescent HRV, such that females have reduced short-term resting state HRV compared to males. Studies on long-term ecological recordings of HRV in adolescents are scarce. The aims of the present study were, (a) to test if adolescent females show decreased long-term HRV and cardiac complexity (CC) compared to males, and (b) to explore whether sex and HRV and CC measures, as well as their interaction, would predict internalizing symptoms. Materials and Methods: HRV was recorded in n = 166 adolescents (86 girls), on a normal school day. HRV and CC measures were calculated on the interbeat interval time series. Results: Females showed lower HRV and CC in most of the assessed indices. Internalizing symptoms were mainly predicted by HRV whereas sex only predicted symptoms of social anxiety. The interaction between sex and HRV did not predict internalizing symptoms. Conclusions: Results suggest that reduced HRV should be considered as a potential contributor to exacerbating internalizing symptoms in adolescence. Girls with reduced HRV and CC might be prone to the development of internalizing disorders. HRV is a promising tool for the early identification of vulnerability.

Non-linear Heart Rate Variability as a Discriminator of Internalizing Psychopathology and Negative Affect in Children With Internalizing Problems and Healthy Controls.

Background: Internalizing psychopathology and dysregulated negative affect are characterized by dysregulation in the autonomic nervous system and reduced heart rate variability (HRV) due to increases in sympathetic activity alongside reduced vagal tone. The neurovisceral system is however, a complex nonlinear system, and nonlinear indices related to psychopathology are so far less studied in children. Essential nonlinear properties of a system can be found in two main domains: the informational domain and the invariant domain. sample entropy (SampEn) is a much-used method from the informational domain, while detrended fluctuation analysis (DFA) represents a widely-used method from the invariant domain. To see if nonlinear HRV can provide information beyond linear indices of autonomic activation, this study investigated SampEn and DFA as discriminators of internalizing psychopathology and negative affect alongside measures of vagally-mediated HRV and sympathetic activation. Material and Methods: Thirty-Two children with internalizing difficulties and 25 healthy controls (aged 9-13) were assessed with the Child Behavior Checklist and the Early Adolescent Temperament Questionnaire, Revised, giving an estimate of internalizing psychopathology, negative affect and effortful control, a protective factor against psychopathology. Five minute electrocardiogram and impedance cardiography recordings were collected during a resting baseline, giving estimates of SampEn, DFA short-term scaling exponent α1, root mean square of successive differences (RMSSD), and pre-ejection period (PEP). Between-group differences and correlations were assessed with parametric and non-parametric tests, and the relationships between cardiac variables, psychopathology and negative affect were assessed using generalized linear modeling. Results: SampEn and DFA were not significantly different between the groups. SampEn was weakly negatively related to heart rate (HR) in the controls, while DFA was moderately negatively related to RMSSD in both groups, and moderately positively related to HR in the clinical sample. SampEn was significantly associated with internalizing psychopathology and negative affect. DFA was significantly related to internalizing psychopathology. Conclusions: Higher invariant self-similarity was linked to less psychopathology. Higher informational entropy was related to less psychopathology and less negative affect, and may provide an index of the organizational flexibility of the neurovisceral system.

Sustained Anxiety Scores are Associated with the Fractal Dynamics of the Heartbeat in Early Adolescents.

The risk of suffering anxiety disorders is associated with sustained subthreshold symptoms of anxiety. This study evaluated the stability of anxiety scores (high, moderate or low) across a six-month period in early adolescents (N = 95). The associations between sustained anxiety, vagally-mediated heart rate variability (vmHRV), sympathetic activity, and heart rate fractal dynamics in everyday life conditions were analyzed. The anxiety scores from 71.50% of participants remained at the same level. The linear correlations between anxiety and cardiac measures were weak but a group-based approach revealed that the fractal dimension (FD) from stable-low anxiety participants was higher than the FD from participants with stable-moderate anxiety scores but not higher than the FD from the stable-high anxiety group. The short-term correlations' exponent a1 from the stable-high anxiety group was higher than the a1 from the stable-moderate anxiety group but not higher than the exponent from the stable-low anxiety group. No differences were found in the vmHRV nor sympathetic activity. The lack of a direct association between the complexity of the heart rate and the level of sustained anxiety suggests a nonlinear pattern of associations that would be in accordance with the optimum variability principle.

Diminished heart rate complexity in adolescent girls: a sign of vulnerability to anxiety disorders?

BACKGROUND AND OBJECTIVES: Diminished heart rate variability has been found to be associated with high anxiety symptomatology. Since adolescence is the period of onset for many anxiety disorders, this study aimed to determine sex- and anxiety-related differences in heart rate variability and complexity in adolescents. METHODS: We created four groups according to sex and anxiety symptomatology: high-anxiety girls (n = 24) and boys (n = 25), and low-anxiety girls (n = 22) and boys (n = 24) and recorded their cardiac function while they performed regular school activities. A series of two-way (sex and anxiety) MANOVAs were performed on time domain variability, frequency domain variability, and non-linear complexity. RESULTS: We obtained no multivariate interaction effects between sex and anxiety, but highly anxious participants had lower heart rate variability than the low-anxiety group. Regarding sex, girls showed lower heart rate variability and complexity than boys. CONCLUSIONS: The results suggest that adolescent girls have a less flexible cardiac system that could be a marker of the girls' vulnerability to developing anxiety disorders.

Trajectories of anxiety symptoms in adolescents: Testing the model of emotional inertia / Trayectoria de la sintomatología ansiosa en adolescentes: poniendo a prueba el modelo de la inercia emocional

Two predictions derived from a recently introduced model of psychotherapy outcome were tested, assuming the dynamical relationship between the individual's emotional trajectory and the force of intervention necessary to change this trajectory: (a) only a high intensity treatment would succeed to lower the increasing trajectory of anxiety, and (b) high as well as low intensity treatments would equivalently lower the non-increasing trajectory of anxiety. Methods: Seventy-four adolescents (58.40% girls; M=14.65 years, SD=0.53) were randomly assigned to a high intensity treatment condition, a low intensity treatment condition, or a waiting list condition. Results: Only the high intensity treatment reduced the anxiety when participants showed an increasing trajectory (p<.01). None of the treatments reduced anxiety when a previously non-increasing trajectory was shown. Conclusions: These findings support the theoretical predictions and underscore the need to consider not only how severe the anxiety is but also the time course of anxiety in applied treatment settings (AU)

Este informe breve tiene por objetivo poner a prueba dos predicciones derivadas de un reciente modelo sobre los resultados en psicoterapia: (a) solo un tratamiento de alta intensidad sería capaz de cambiar de dirección una trayectoria ascendente de ansiedad, y (b) tanto un tratamiento de alta como de baja intensidad podrían influir en una trayectoria no-ascendente de ansiedad. Método: Setenta y cuatro adolescentes (58,40% chicas; M=14,65 años, DT=0,53) fueron asignados aleatoriamente a una de estas condiciones: tratamiento de alta intensidad, tratamiento de baja intensidad o lista de espera. Resultados: Solo la aplicación del tratamiento de alta intensidad permitió reducir los niveles de ansiedad en los adolescentes con trayectoria creciente de dicha sintomatología (p<0,01). Además, ambos tratamientos redujeron de forma equivalente la sintomatología en individuos con trayectoria no ascendente de ansiedad. Conclusiones: Estos resultados apoyan las predicciones teóricas propuestas y subrayan la necesidad de considerar no solamente la magnitud de la sintomatología ansiosa sino también su curso temporal, en contextos clínicos (AU)

Allometric Control of Affective Fluctuations in Early Adolescents: Their Association with Anxiety Symptoms and Temperament Traits.

Many physiological systems are multistable, i.e. they operate at different time scales under an allometric control process. The multistability of affective fluctuations has been clearly illustrated in a sample of adults, but little is known about their dynamics in adolescents. The main aim of this study was to determine whether affective fluctuations in adolescents show multistability and to explore their relationship with anxiety symptomatology and temperamental factors. Twenty-five early adolescents self-reported their daily mood, anxiety and worry levels twice a day over a 100-day period. The time series were analysed using the allometric aggregation method to obtain the scaling exponent h. Almost all the (Hurst) scaling exponents were 0.5 > h > 1. The worry exponents were related to temperament factors, whereas the anxiety exponents were related to social phobia symptoms. The results substantiate that affective fluctuations in adolescents are multistable, lending support to the presence of allometric control mechanisms.

Impaired cardiac profile in adolescents with an increasing trajectory of anxiety when confronting an acute stressor.

Maladaptive patterns of cardiac adjustment to stress in adolescents may reveal their vulnerability to anxiety disorders (ADs). Traditional research in this field has focused on anxiety levels, whereas the time course of anxiety has rarely been considered. Nevertheless, since overall anxiety decreases as adolescence progresses, increasing time courses are clinically relevant and can be associated with maladaptive contextual adjustment. In this study, the cardiac pattern of adjustment to stress in adolescents with increasing anxiety was analysed. A sample of 44 adolescents (M = 14.88 years, SD = 0.53, 45.45% boys) were exposed to a socially relevant stress induction protocol, and their cardiac functioning was recorded. Participants with a trajectory of increasing anxious symptomatology over a 12-month period (n = 24) showed attenuated heart rate levels in the stage of maximum stress in comparison to their non-increasing anxious counterparts (p < 0.05), as well as a heightened pattern of sample entropy throughout the stress induction (p < 0.05). These findings suggest a loss of cardiac flexibility in those adolescents at risk of ADs when confronting an acute stressor.