Children with social phobia have lower quality friendships than children with other anxiety disorders.

BACKGROUND AND OBJECTIVE: Whilst shy, socially anxious or socially withdrawn children in nonclinical community samples report lower friendship quality (FQ) than nonanxious children, no study has examined the FQ of clinically anxious children. The aim of the study was to examine the FQ of children with anxiety disorders; and whether it differs for clinical children with or without a diagnosis of social phobia (SP). DESIGN: The study design was cross-sectional self-report. METHODS: Clinical children - 39 anxiety-disordered children with SP and 28 anxiety-disordered children without SP (No-SP) - presented for psychological treatment, and 29 nonclinical children were recruited from the community. Same-sex close friends were invited to participate using an unrestricted nomination procedure. All children were aged between 7 and 13 years. Both target child and friend completed the Friendship Quality Questionnaire and the Spence Children's Anxiety Scale. RESULTS: Using multilevel modeling within the framework of the Actor-Partner Interdependence Model, SP dyads were found to report lower overall FQ than No-SP dyads. SP dyads did not report lower overall FQ than nonclinical dyads. CONCLUSION: Children with SP in their diagnostic profile may be unique in their friendship experiences relative to children with other anxiety disorders.

Serotonin transporter [corrected] methylation and response to cognitive behaviour therapy in children with anxiety disorders.

Anxiety disorders that are the most commonly occurring psychiatric disorders in childhood, are associated with a range of social and educational impairments and often continue into adulthood. Cognitive behaviour therapy (CBT) is an effective treatment option for the majority of cases, although up to 35-45% of children do not achieve remission. Recent research suggests that some genetic variants may be associated with a more beneficial response to psychological therapy. Epigenetic mechanisms such as DNA methylation work at the interface between genetic and environmental influences. Furthermore, epigenetic alterations at the serotonin transporter (SERT) promoter region have been associated with environmental influences such as stressful life experiences. In this study, we measured DNA methylation upstream of SERT in 116 children with an anxiety disorder, before and after receiving CBT. Change during treatment in percentage DNA methylation was significantly different in treatment responders vs nonresponders. This effect was driven by one CpG site in particular, at which responders increased in methylation, whereas nonresponders showed a decrease in DNA methylation. This is the first study to demonstrate differences in SERT methylation change in association with response to a purely psychological therapy. These findings confirm that biological changes occur alongside changes in symptomatology following a psychological therapy such as CBT.

An investigation into the lower peer liking of anxious than nonanxious children.

Peer dislike of anxious behaviour was investigated in 7-12 year olds. Child actors delivered an identical verbal presentation: once in an anxious manner and once confidently. The videos were rated for liking and seven potential mediators by three groups of children: 32 anxiety-disordered peers with social phobia; 16 anxiety-disordered peers without social phobia; and 48 nonclinical peers. A mediation model with moderation effects was tested within a within-subjects framework. "Anxious" actors were liked significantly less than "confident" actors. This effect differed by group rater, in that relative dislike of the anxious actor was significantly greater for the nonclinical than socially phobic raters. Physical attractiveness and friend acceptance mediated the effect for all group raters. Other identified mediators differed depending upon the group rater. The findings direct future efforts to help anxiety-disordered children circumvent an increased risk of negative peer relations, and testify to consideration of the rater in sociometric studies.

Friendship quality and social information processing in clinically anxious children.

The association between perceived friendship quality (FQ) and social information processing (SIP) was examined in three groups of children and their close friends aged 7-12 years: 16 anxiety disordered children with social phobia (SP); 12 anxiety disordered children without SP (No-SP); and 32 nonclinical children. Positive and negative FQ positively associated with target children's positive and negative responding on a vignette measure of SIP. SP children reported lower positive SIP than No-SP but not nonclinical children; and this was the only group difference in SIP. Target children and their friends were similar in negative but not positive SIP. Following discussion about the vignette with a close friend, all target children increased in positive SIP; negative SIP did not change. Lower FQ and a more socially anxious friend predicted higher negative target child SIP postdiscussion. Close friendships play an important role in the SIP of both clinical and nonclinical children.

Display of consistent ictal networks in refractory mesial temporal lobe epilepsy.

OBJECTIVE: Exploration of emergent ictal networks was performed in homogeneous subjects with refractory medial temporal lobe epilepsy. METHODS: Maximal Synchrony Index (SI) values were calculated for all electrode pairs for each second during 25 seizures and displayed as connectivity animations. Consistent temporal patterns of SI value and spatial connectivity were observed across seizures and subjects, and used to define a sequence of network stages. RESULTS: Highest SI values were found in electrodes within the area of surgical resection. Analysis of these electrodes by network stage demonstrated lateral temporal cortex dominance at seizure initiation, giving way to hippocampal synchrony during the major portion of the seizure, with lateral temporal regions re-emerging as the seizure terminated. SI values also corresponded to behavioral severity of seizures, and lower SI values were associated with post-surgical seizure freedom. CONCLUSION: SI based methods of network characterization consistently display the intrinsic MTLE ictal network and may be sensitive to clinical features. SIGNIFICANCE: Consistency of EEG-derived network patterns is an important step as network features are applied towards improvement of clinical management. These data confirm consistency of network patterns within and across subjects and support the potential for these methods to distinguish relevant clinical variables.

Friendship quality predicts treatment outcome in children with anxiety disorders.

It was examined whether friendship quality (FQ) and friends' anxiety predicted treatment outcome in 116 children with anxiety disorders (72.3% Australian) receiving cognitive behavioural therapy (CBT). Target children and an identified close friend aged between 7 and 13 years (50% female) completed the Friendship Quality Questionnaire (Parker & Asher, 1993) before treatment, and child diagnoses were based on the Anxiety Disorders Interview Schedule for DSM-IV-Child/Parent Version (Silverman & Albano, 1996). Children who reported higher FQ were significantly more likely to be free of their initial primary anxiety disorder and of any anxiety disorder at posttreatment and 6-month follow-up; friend report of FQ and friend's anxiety as measured by the Spence Child Anxiety Scale (Spence, 1998) did not predict treatment outcome. Children with anxiety disorders reporting higher FQ responded better to CBT than children with anxiety disorders reporting lower FQ. FQ measures could help identify anxious children at heightened risk of poor treatment response. Further, good quality friendships may be an important aid in anxious children's treatment response.

Neurotrophic gene polymorphisms and response to psychological therapy.

Therapygenetics, the study of genetic determinants of response to psychological therapies, is in its infancy. Here, we investigate whether single-nucleotide polymorphisms in nerve growth factor (NGF) (rs6330) and brain-derived neutrotrophic factor (BDNF) (rs6265) genes predict the response to cognitive behaviour therapy (CBT). Neurotrophic genes represent plausible candidate genes: they are implicated in synaptic plasticity, response to stress, and are widely expressed in brain areas involved in mood and cognition. Allelic variation at both loci has shown associations with anxiety-related phenotypes. A sample of 374 anxiety-disordered children with white European ancestry was recruited from clinics in Reading, UK, and in Sydney, Australia. Participants received manualised CBT treatment and DNA was collected from buccal cells using cheek swabs. Treatment response was assessed at post-treatment and follow-up time points. We report first evidence that children with one or more copies of the T allele of NGF rs6330 were significantly more likely to be free of their primary anxiety diagnosis at follow-up (OR = 0.60 (0.42-0.85), P = 0.005). These effects remained even when other clinically relevant covariates were accounted for (OR = 0.62 (0.41-0.92), P = 0.019). No significant associations were observed between BDNF rs6265 and response to psychological therapy. These findings demonstrate that knowledge of genetic markers has the potential to inform clinical treatment decisions for psychotherapeutic interventions.

An automated algorithm for the generation of dynamically reconstructed trajectories.

The lack of long enough data sets is a major problem in the study of many real world systems. As it has been recently shown [C. Komalapriya, M. Thiel, M. C. Romano, N. Marwan, U. Schwarz, and J. Kurths, Phys. Rev. E 78, 066217 (2008)], this problem can be overcome in the case of ergodic systems if an ensemble of short trajectories is available, from which dynamically reconstructed trajectories can be generated. However, this method has some disadvantages which hinder its applicability, such as the need for estimation of optimal parameters. Here, we propose a substantially improved algorithm that overcomes the problems encountered by the former one, allowing its automatic application. Furthermore, we show that the new algorithm not only reproduces the short term but also the long term dynamics of the system under study, in contrast to the former algorithm. To exemplify the potential of the new algorithm, we apply it to experimental data from electrochemical oscillators and also to analyze the well-known problem of transient chaotic trajectories.

The Cool Teens CD-ROM for anxiety disorders in adolescents : a pilot case series.

Five adolescents received a multimedia CD-ROM containing a self-help treatment program for young people with an anxiety disorder. Participants used the 8-module Cool Teens CD-ROM over a 12-week period on a home computer. Every 2 weeks, they received a brief telephone call from a clinical psychologist to monitor symptoms and progress and to discuss any problems with understanding content or implementing techniques. Based on structured interviews, two participants (40%) no longer met diagnostic criteria (self-report ADIS) for at least one clinical anxiety disorder immediately following treatment and these same participants no longer met diagnostic criteria for any clinical anxiety disorder at 3-month follow-up. Two other participants failed to make gains based on diagnostic criteria, but showed improvement in anxiety symptoms for one main fear. Participants were generally satisfied with the multimedia content, the modules, and the delivery format of the program.

Adaptive control of unknown unstable steady states of dynamical systems.

A simple adaptive controller based on a low-pass filter to stabilize unstable steady states of dynamical systems is considered. The controller is reference-free; it does not require knowledge of the location of the fixed point in the phase space. A topological limitation similar to that of the delayed feedback controller is discussed. We show that the saddle-type steady states cannot be stabilized by using the conventional low-pass filter. The limitation can be overcome by using an unstable low-pass filter. The use of the controller is demonstrated for several physical models, including the pendulum driven by a constant torque, the Lorenz system, and an electrochemical oscillator. Linear and nonlinear analyses of the models are performed and the problem of the basins of attraction of the stabilized steady states is discussed. The robustness of the controller is demonstrated in experiments and numerical simulations with an electrochemical oscillator, the dissolution of nickel in sulfuric acid; a comparison of the effect of using direct and indirect variables in the control is made. With the use of the controller, all unstable phase-space objects are successfully reconstructed experimentally.

Sudden onset of pitting corrosion on stainless steel as a critical phenomenon.

Stainless steels undergo a sharp rise in pitting corrosion rate as the potential, solution concentration, or temperature is changed only slightly. We report experiments using real-time microscopic in situ visualizations that resolve the nucleation and evolution of individual pits during the transition. They suggest that the sudden onset of corrosion is explained by an explosive autocatalytic growth in the number of metastable pits and that stabilization of individual pits takes place only later. This finding agrees with a theoretical approach treating the onset of pitting corrosion as a cooperative critical phenomenon resulting from interactions among metastable pits, and it extends perspectives on the control and prevention of corrosion onset.

Cooperative action of coherent groups in broadly heterogeneous populations of interacting chemical oscillators.

We present laboratory experiments on the effects of global coupling in a population of electrochemical oscillators with a multimodal frequency distribution. The experiments show that complex collective signals are generated by this system through spontaneous emergence and joint operation of coherently acting groups representing hierarchically organized resonant clusters. Numerical simulations support these experimental findings. Our results suggest that some forms of internal self-organization, characteristic for complex multiagent systems, are already possible in simple chemical systems.

Spatial learning deficits induced by muscimol and CL218,872: lack of effect of prenatal malnutrition.

The sensitivity of prenatal protein malnourished rats to the amnestic properties of the direct GABAA receptor agonist muscimol and the selective benzodiazepine (BZ) receptor agonist, CL218,872, was studied in the male offspring of rats provided with a protein deficient diet (6% casein) for 5 weeks prior to mating and throughout pregnancy. At postnatal day 90, rats were tested during acquisition of the submerged platform version of the Morris water maze task using four systemic doses of muscimol (0.1, 0.3, 1.0 and 1.8 mg/kg i.p.) or three systemic doses of CL218,872 (1.0, 3.2, and 5.6 mg/kg i.p.). In a dose dependent manner both drugs impaired acquisition of the task and impaired accuracy of the search pattern on the probe trial (platform removed). However, neither drug dissociated the performance of the two nutritional groups. These data are important in light of previous findings of differential behavioral effects of the non-specific BZ agonist, chlordiazepoxide (CDP), on spatial learning and on drug discrimination in prenatally malnourished rats and in the context of previous findings of reduced sensitivity to the anxiolytic effects of non-specific BZ receptor agonists across a wide variety of models of malnutrition. The present findings also support the concept that prenatal malnutrition does not affect the global functioning of the GABAA receptor, but fundamentally alters the way in which a subset of GABAA receptors (i.e. those containing the alpha2, alpha3 and/or the alpha5 but not the alpha1 subunit) is modulated by BZs.

Stabilizing and tracking unknown steady States of dynamical systems.

An adaptive dynamic state feedback controller for stabilizing and tracking unknown steady states of dynamical systems is proposed. We prove that the steady state can never be stabilized if the system and controller in sum have an odd number of real positive eigenvalues. For two-dimensional systems, this topological limitation states that only an unstable focus or node can be stabilized with a stable controller, and stabilization of a saddle requires the presence of an unstable degree of freedom in a feedback loop. The use of the controller to stabilize and track saddle points (as well as unstable foci) is demonstrated both numerically and experimentally with an electrochemical Ni dissolution system.

Suppressing spatiotemporal disorder via local perturbations in an electrochemical cell.

We report experimental results depicting suppression of complex spatiotemporal dynamics under the influence of local periodic stimulations. In an experimental electrochemical system, applying a continuous forcing signal to one of the sites in an array of eight coupled oscillators, the naturally complex behavior of the remaining seven electrodes can be converted to periodic responses. The oscillations remain periodic as long as the forcing is active and revert back to exhibiting chaotic dynamics after the control is switched off. These results can also be interpreted as experimental realization of "phase-synchronization" induced via local driving in an extended system. A possible relevance to the experimentally observed calcium wave patterns is pointed out.

Phase synchronization and suppression of chaos through intermittency in forcing of an electrochemical oscillator.

External periodic forcing was applied to a chaotic chemical oscillator in experiments on the electrodissolution of Ni in sulfuric acid solution. The amplitude and the frequency (Omega) of the forcing signal were varied in a region around Omega=omega(0), where omega(0) is the frequency of the unforced signal. Phase synchronization occurred with increase in the amplitude of the forcing. For Omega/omega(0) near 1 the signal remained chaotic after the transition to the phase-locked state; for Omega/omega(0) somewhat farther from 1 the transition was to a periodic state via intermittency. The experimental results are supported by numerical simulations using a general model for electrochemical oscillations.

Controlling spatiotemporal chemical chaos using delayed feedback.

Control of chemical chaos in a spatially extended system mimicking CO oxidation on a Pt(110) single-crystal surface is achieved using delayed feedback techniques. For appropriate parameter values the uncontrolled model system exhibits both amplitude and phase turbulence. Superimposing a delayed feedback on the natural dynamics, suppression of spatiotemporal complexity is attained via stabilization of ordered states consisting of stable patterns.

Clustering of arrays of chaotic chemical oscillators by feedback and forcing.

Feedback and external forcing are applied to an array of chaotic electrochemical oscillators through variations in the applied potential. We see transitions from intermittent clusters to stable chaotic clusters to stable periodic clusters to synchronized states as the feedback gain and forcing amplitude, respectively, are varied. With forcing up to four clusters are observed in stable states. The transition to synchronization with feedback occurs by the increase in the size of one cluster at the expense of the others.

Spatiotemporal patterns and symmetry breaking on a ring electrode.

A series of experiments on a ring electrode with changes in a parameter, the applied potential, are described. Spatiotemporal patterns are investigated in a region of parameter space in which relaxation oscillations occur. The simplest state is a period 2Pi oscillation that has full O(2) symmetry so that at each instant the pattern is unchanged by rotations or reflections of the ring. With change in parameter a spatiotemporal period doubling occurs to period 4Pi. This is followed by a symmetry breaking to another state with period 4Pi and subsequently by a second period doubling to period 8Pi. Proper orthogonal decomposition is used as an aid in elucidating the nature of the transitions.