Developmental changes in startle reactivity in school-age children at risk for and with actual anxiety disorder

Effects of early childhood behavioral inhibition and parental anxiety disorder on adolescents' startle response to predictable and unpredictable threat

Numerous studies in children, adolescents and adults have reported that anxiety disorders and symptoms are associated with greater threat-potentiated startle responses. This suggests that it may also be related to risk factors that have been implicated in the genesis of anxiety disorders. Therefore, we examined the roles of early childhood temperamental behavioral inhibition (BI) and parental history of anxiety disorders in predicting threat-potentiated startle response in a community sample of 346 adolescents. Parental history of anxiety disorders moderated the effects of BI on subsequent startle responses. For both total startle response and unpredictable threat startle potentiation, higher levels of BI at age 3 predicted larger startle responses at age 15, but only among offspring of parents with a history of anxiety disorders. Among offspring of parents with no lifetime history of anxiety disorder, BI was unrelated to startle magnitude. These findings were evident even after adjusting for youth's biological sex, concurrent anxiety symptoms, and lifetime history of anxiety disorders. In contrast, neither BI nor parental anxiety significantly predicted startle potentiation to predictable threat. These findings have implications for tracing pathways to the development of anxiety disorders.

Role of the Neuropeptide S System in Emotionality, Stress Responsiveness and Addiction-Like Behaviours in Rodents: Relevance to Stress-Related Disorders

The neuropeptide S (NPS) and its receptor (NPSR1) have been extensively studied over the last two decades for their roles in locomotion, arousal/wakefulness and anxiety-related and fear-related behaviours in rodents. However, the possible implications of the NPS/NPSR1 system, especially those of the single nucleotide polymorphism (SNP) rs324981, in stress-related disorders and substance abuse in humans remain unclear. This is possibly due to the fact that preclinical and clinical research studies have remained separated, and a comprehensive description of the role of the NPS/NPSR1 system in stress-relevant and reward-relevant endpoints in humans and rodents is lacking. In this review, we describe the role of the NPS/NPSR1 system in emotionality, stress responsiveness and addiction-like behaviour in rodents. We also summarize the alterations in the NPS/NPSR1 system in individuals with stress-related disorders, as well as the impact of the SNP rs324981 on emotion, stress responses and neural activation in healthy individuals. Moreover, we discuss the therapeutic potential and possible caveats of targeting the NPS/NPSR1 system for the treatment of stress-related disorders. The primary goal of this review is to highlight the importance of studying some rodent behavioural readouts modulated by the NPS/NPSR1 system and relevant to stress-related disorders.

The effect of polymorphisms in startle-related genes on anxiety symptom severity

Given the limited effectiveness of treatments for pathological anxiety, there is a pressing need to identify genetic markers that can aid the precise selection of treatments and optimize treatment response. Anxiety and startle response levels demonstrate a direct relationship, and previous literature suggests that exaggerated startle reactivity may serve as an endophenotype of pathological anxiety. In addition, genetic variants related to startle reactivity may play a role in the etiology of pathological anxiety. In the current study, we selected 22 single nucleotide polymorphisms (SNPs) related to startle reactivity in the literature, and examined their association with anxiety symptom severity across psychiatric disorders (n = 508), and in a subset of patients with an anxiety disorder (n = 298). Overall, none of the SNPs pass correction for multiple independent tests. However, across psychiatric patients, rs6323 from the monoamine oxidase A (MAOA) gene and rs324981 from the neuropeptide S receptor 1 (NPSR1) gene were nominally associated with baseline anxiety symptom severity (p = 0.017, 0.023). These preliminary findings provide support for investigating startle-related genetic variants to identify biomarkers of anxiety symptom severity.

Towards precision medicine in generalized anxiety disorder: Review of genetics and pharmaco(epi)genetics

Generalized anxiety disorder (GAD) is a prevalent and chronic mental disorder that elicits widespread functional impairment. Given the high degree of non-response/partial response among patients with GAD to available pharmacological treatments, there is a strong need for novel approaches that can optimize outcomes, and lead to medications that are safer and more effective. Although investigations have identified interesting targets predicting treatment response through pharmacogenetics (PGx), pharmaco-epigenetics, and neuroimaging methods, these studies are often solitary, not replicated, and carry several limitations. This review provides an overview of the current status of GAD genetics and PGx and presents potential strategies to improve treatment response by combining better phenotyping with PGx and improved analytical methods. These strategies carry the dual benefit of delivering data on biomarkers of treatment response as well as pointing to disease mechanisms through the biology of the markers associated with response. Overall, these efforts can serve to identify clinical, genetic, and epigenetic factors that can be incorporated into a pharmaco(epi)genetic test that may ultimately improve treatment response and reduce the socioeconomic burden of GAD.

Developmental Contributors to Trauma Response: The Importance of Sensitive Periods, Early Environment, and Sex Differences

This review considers early factors that interact with development to contribute to later trauma responses, including developmental sensitive periods, the effects of early environment, and the emergence of sex differences. We also describe development of neural substrates that have been associated with posttraumatic stress disorder and specifically focus on fear behavior and circuitry. Emerging evidence suggests that there may be developmental shifts around age 10 in these underlying circuits that may contribute to vulnerability. We also discuss age-related changes in the importance of caregiver availability as positive buffering factors. Hormonal changes later in development with onset during puberty appear to further shape development trajectories toward risk or resilience. We highlight these recent findings as well as the great need for further longitudinal research from middle childhood through early adulthood.

Wearable sensors detect childhood internalizing disorders during mood induction task

There is a significant need to develop objective measures for identifying children under the age of 8 who have anxiety and depression. If left untreated, early internalizing symptoms can lead to adolescent and adult internalizing disorders as well as comorbidity which can yield significant health problems later in life including increased risk for suicide. To this end, we propose the use of an instrumented fear induction task for identifying children with internalizing disorders, and demonstrate its efficacy in a sample of 63 children between the ages of 3 and 7. In so doing, we extract objective measures that capture the full six degree-of-freedom movement of a child using data from a belt-worn inertial measurement unit (IMU) and relate them to behavioral fear codes, parent-reported child symptoms and clinician-rated child internalizing diagnoses. We find that IMU motion data, but not behavioral codes, are associated with parent-reported child symptoms and clinician-reported child internalizing diagnosis in this sample. These results demonstrate that IMU motion data are sensitive to behaviors indicative of child psychopathology. Moreover, the proposed IMU-based approach has increased feasibility of collection and processing compared to behavioral codes, and therefore should be explored further in future studies.

Movements Indicate Threat Response Phases in Children at Risk for Anxiety

Temporal phases of threat response, including potential threat (anxiety), acute threat (startle, fear), and post-threat response modulation, have been identified as the underlying markers of anxiety disorders. Objective measures of response during these phases may help identify children at risk for anxiety; however, the complexity of current assessment techniques prevent their adoption in many research and clinical contexts. We propose an alternative technology, an inertial measurement unit (IMU), that enables noninvasive measurement of the movements associated with threat response, and test its ability to detect threat response phases in young children at a heightened risk for developing anxiety. We quantified the motion of 18 children (3-7 years old) during an anxiety-/fear-provoking behavioral task using an IMU. Specifically, measurements from a single IMU secured to the child's waist were used to extract root-mean-square acceleration and angular velocity in the horizontal and vertical directions, and tilt and yaw range of motion during each threat response phase. IMU measurements detected expected differences in child motion by threat phase. Additionally, potential threat motion was positively correlated to familial anxiety risk, startle range of motion was positively correlated with child internalizing symptoms, and response modulation motion was negatively correlated to familial anxiety risk. Results suggest differential theory-driven threat response phases and support previous literature connecting maternal child risk to anxiety with behavioral measures using more feasible objective methods. This is the first study demonstrating the utility of an IMU for characterizing the motion of young children to mark the phases of threat response modulation. The technique provides a novel and objective measure of threat response for mental health researchers.

Contextual startle responses moderate the relation between behavioral inhibition and anxiety in middle childhood

Behavioral inhibition (BI), a temperament characterized in early childhood by wariness and avoidance of novelty, is a risk factor for anxiety disorders. An enhanced startle response has been observed in adolescents characterized with BI in childhood, particularly when they also manifest concurrent symptoms of anxiety. However, no prior study has examined relations among BI, startle responsivity, and anxiety in a prospective manner. Data for the present study were from a longitudinal study of infant temperament. Maternal reports and observations of BI were assessed at ages 2 and 3. At age 7, participants completed a startle procedure, while electromyography was collected, where participants viewed different colors on a screen that were associated with either the delivery of an aversive stimulus (i.e., puff of air to the larynx; threat cue) or the absence of the aversive stimulus (i.e., safety cue). Parental reports of child anxiety were collected when children were 7 and 9 years of age. Results revealed that startle responses at age 7 moderated the relation between early BI and 9-year anxiety. These findings provide insight into one potential mechanism that may place behaviorally inhibited children at risk for anxiety.

Habituation of parasympathetic-mediated heart rate responses to recurring acoustic startle

Startle habituation is a type of implicit and automatic emotion regulation. Diminished startle habituation is linked to several psychiatric or neurological disorders. Most previous studies quantified startle habituation by assessing skin conductance response (SCR; reflecting sympathetic-mediated sweating), eye-blink reflex, or motor response. The habituation of parasympathetic-mediated heart rate responses to recurrent startle stimuli is not well understood. A variety of methods and metrics have been used to quantify parasympathetic activity and its effects on the heart. We hypothesized that these different measures reflect unique psychological and physiological processes that may habituate differently during repeated startle stimuli. We measured cardiac inter-beat intervals (IBIs) to recurring acoustic startle probes in 75 eight year old children. Eight acoustic stimuli of 500 ms duration were introduced at intervals of 15-25 s. Indices of parasympathetic effect included: (1) the initial rapid decrease in IBI post-startle mediated by parasympathetic inhibition (PI); (2) the subsequent IBI recovery mediated by parasympathetic reactivation (PR); (3) rapid, beat-to-beat heart rate variability (HRV) measured from the first seven IBIs following each startle probe. SCR and motor responses to startle were also measured. Results showed that habituation of PR (IBI recovery and overshoot) and SCRs were rapid and robust. In addition, changes in PR and SCR were significantly correlated. In contrast, habituation of PI (the initial decrease in IBI) was slower and relatively modest. Measurement of rapid HRV provided an index reflecting the combination of PI and PR. We conclude that different measures of parasympathetic-mediated heart rate responses to repeated startle probes habituate in a differential manner.

Developmental investigation of fear-potentiated startle across puberty

The goal of this study was to examine the association between affective development, puberty, and gender using the startle reflex as a marker of defensive mechanisms. Thirty-one male and thirty-five female adolescents aged ten to thirteen participated in a prospective study with up to five assessments. Longitudinal analyses revealed a significant effect of sex, with girls showing stronger fear-potentiation at all pubertal stages. Post hoc tests revealed that fear-potentiation increased in girls but not boys over the course of puberty. Furthermore, baseline startle decreased over the course of puberty. Because age was included as a covariate in all analyses, the puberty effect cannot be accounted for by age. To the best of our knowledge, this study provides the first evidence for a significant increase in fear-potentiated startle across the pubertal transition. Attribution of these changes to pubertal status rather than age has important implications for our understanding of the neurobiology of anxiety and affect regulation.

Who is predisposed to insomnia: a review of familial aggregation, stress-reactivity, personality and coping style

Insomnia is a common health complaint world-wide. Insomnia is a risk factor in the development of other psychological and physiological disorders. Therefore understanding the mechanisms which predispose an individual to developing insomnia has great transdiagnostic value. However, whilst it is largely accepted that a vulnerable phenotype exists there is a lack of research which aims to systematically assess the make-up of this phenotype. This review outlines the research to-date, considering familial aggregation and the genetics and psychology of stress-reactivity. A model will be presented in which negative affect (neuroticism) and genetics (5HTTLPR) are argued to lead to disrupted sleep via an increase in stress-reactivity, and further that the interaction of these variables leads to an increase in learned negative associations, which further increase the likelihood of poor sleep and the development of insomnia.

Individual differences in fear potentiated startle in behaviorally inhibited children

Behavioral inhibition (BI) is a temperament characterized during early childhood by increased fearfulness to novelty, social reticence to unfamiliar peers, and heightened risk for the development of anxiety. Heightened startle responses to safety cues have been found among behaviorally inhibited adolescents who have an anxiety disorder suggesting that this measure may serve as a biomarker for the development of anxiety amongst this risk population. However, it is unknown if these aberrant startle patterns emerge prior to the manifestation of anxiety in this temperament group. The current study examined potentiated startle in 7-year-old children characterized with BI early in life. High behaviorally inhibited children displayed increased startle magnitude to safety cues, particularly during the first half of the task, and faster startle responses compared to low behaviorally inhibited children. These findings suggest that aberrant startle responses are apparent in behaviorally inhibited children during early childhood prior to the onset of a disorder and may serve as a possible endophenotype for the development of anxiety.

The School Anxiety Scale-Teacher Report (SAS-TR): translation and psychometric properties of the Iranian version

BACKGROUND

The School Anxiety Scale-Teacher Report (SAS-TR) was designed to assess anxiety in children at school. The SAS-TR is a proxy rated measure and could assess social anxiety, generalized anxiety and also gives a total anxiety score. This study aimed to translate and validate the SAS-TR in Iran.

METHODS

The translation and cultural adaptation of the original questionnaire were carried out in accordance with the published guidelines. A sample of students participated in the study. Reliability was estimated using internal consistency and test-retest analysis. Validity was assessed using content validity. The factor structure of the questionnaire was extracted by performing both exploratory and confirmatory factor analyses.

RESULTS

In all 200 elementary students aged 6 to 10 years were studied. Considering the recommended cut-off values, overall the prevalence of high anxiety condition in elementary students was found to be 21 %. Cronbach's alpha coefficient for the Iranian SAS-TR was 0.92 and intraclass correlation coefficient (ICC) was found to be 0.81. The principal component analysis indicated a two-factor structure for the questionnaire (generalized and social anxiety) that jointly accounted for 55.3 % of variances observed. The confirmatory factory analysis also indicated a good fit to the data for the two-latent structure of the questionnaire.

CONCLUSION

In general the findings suggest that the Iranian version of SAS-TR has satisfactory reliability, and validity for measuring anxiety in 6 to 10 years old children in Iran. It is simple and easy to use and now can be applied in future studies.

Reconceptualizing antisocial deviance in neurobehavioral terms

We propose that neuroscientific understanding of antisocial behavior can be advanced by focusing programmatic efforts on neurobehavioral trait constructs, that is, individual difference constructs with direct referents in neurobiology as well as behavior. As specific examples, we highlight inhibitory control and defensive reactivity as two such constructs with clear relevance for understanding antisocial behavior in the context of development. Variations in inhibitory control are theorized to reflect individual differences in the functioning of brain systems that operate to guide and inhibit behavior and regulate emotional response in the service of nonimmediate goals. Variations in defensive reactivity are posited to reflect individual differences in the sensitivity of the brain's aversive motivational (fear) system. We describe how these constructs have been conceptualized in the adult and child literatures and review work pertaining to traditional psychometric (rating and behaviorally based) assessment of these constructs and their known physiological correlates at differing ages as well as evidence linking these constructs to antisocial behavior problems in children and adults. We outline a psychoneurometric approach, which entails systematic development of neurobiological measures of target trait constructs through reference to psychological phenotypes, as a paradigm for linking clinical disorders to neurobiological systems. We provide a concrete illustration of this approach in the domain of externalizing proneness and discuss its broader implications for research on conduct disorder, antisocial personality, and psychopathy.

Physiological markers of anxiety are increased in children of abused mothers

BACKGROUND

A growing number of studies indicate that low income, African American men and women living in urban environments are at high risk for trauma exposure, which may have intergenerational effects. The current study employed psychophysiological methods to describe biomarkers of anxiety in children of traumatized mothers.

METHODS

Study participants were recruited from a highly traumatized urban population, comprising mother-child pairs (n=36) that included school-age children. Mothers were assessed for childhood abuse with the Childhood Trauma Questionnaire, as well as symptoms of depression and posttraumatic stress disorder (PTSD). The children were measured for dark-enhanced startle responses and heart-rate variability.

RESULTS

Dark-enhanced startle was found to be higher in children whose mothers had high levels of childhood physical abuse, as compared to children whose mothers had low levels of physical abuse. During the habituation phase of the startle experiment, children whose mothers had high levels of childhood emotional abuse had higher sympathetic system activation compared to children of mothers with low emotional abuse. These effects remained significant after accounting for maternal symptoms of PTSD and depression, as well as for the child's trauma exposure.

CONCLUSION

These results demonstrate that children of mothers who have history of childhood physical and emotional abuse have higher dark-enhanced startle as well as greater sympathetic nervous system activation than children of mothers who do not report a history of childhood physical and emotional abuse, and emphasize the utility of physiological measures as pervasive biomarkers of psychopathology that can easily be measured in children.

Emotion-modulated startle in anxiety disorders is blunted by co-morbid depressive episodes

BACKGROUND

While anxiety has been associated with exaggerated emotional reactivity, depression has been associated with blunted, or context insensitive, emotional responding. Although anxiety and depressive disorders are frequently co-morbid, surprisingly little is known about emotional reactivity when the two disorders co-occur.

METHOD

We utilized the emotion-modulated startle (EMS) paradigm to examine the effects of a concurrent depressive episode on emotional reactivity in young adults with anxiety disorders. Using an archival dataset from a multi-disciplinary project on risk factors in childhood-onset depression, we examined eye-blink startle reactions to late-onset auditory startle probes while participants viewed pictures with affectively pleasant, unpleasant and neutral content. EMS response patterns were analyzed in 33 individuals with a current anxiety (but no depressive) disorder, 24 individuals with a current anxiety disorder and co-morbid depressive episode and 96 healthy controls.

RESULTS

Control participants and those with a current anxiety disorder (but no depression) displayed normative linearity in startle responses, including potentiation by unpleasant pictures. By contrast, individuals with concurrent anxiety and depression displayed blunted EMS.

CONCLUSIONS

An anxiety disorder concurrent with a depressive episode is associated with reactivity that more closely resembles the pattern of emotional responding that is typical of depression (i.e. context insensitive) rather than the pattern that is typical for anxiety (i.e. exaggerated).

The startle response: developmental effects and a paradigm for children and adults

A film paradigm was developed to examine baseline and emotion modulated startle across a broad age range from preschool to adulthood. The paradigm was tested in children (3-, 5-, 7-, and 9-year-olds) and adults (total N = 122). The paradigm elicited a similar startle potentiation pattern across age groups; however, baseline startle changed with age: 3- and 5-year-olds showed lower response probability and magnitude of baseline startle than adults. Females exhibited larger baseline startle response probability and overall magnitude than did males; however, no sex by emotion modulated startle interaction was noted. Anxiety measures were obtained for all children. Individual differences in anxiety were associated with baseline startle magnitude among older but not younger children. No association of anxiety with startle potentiation was noted. Overall the film paradigm was applicable across a wide developmental span, revealing potential developmental and gender differences in baseline startle magnitude and response probability.

Phasic vs sustained fear in rats and humans: role of the extended amygdala in fear vs anxiety

Data will be reviewed using the acoustic startle reflex in rats and humans based on our attempts to operationally define fear vs anxiety. Although the symptoms of fear and anxiety are very similar, they also differ. Fear is a generally adaptive state of apprehension that begins rapidly and dissipates quickly once the threat is removed (phasic fear). Anxiety is elicited by less specific and less predictable threats, or by those that are physically or psychologically more distant. Thus, anxiety is a more long-lasting state of apprehension (sustained fear). Rodent studies suggest that phasic fear is mediated by the amygdala, which sends outputs to the hypothalamus and brainstem to produce symptoms of fear. Sustained fear is also mediated by the amygdala, which releases corticotropin-releasing factor, a stress hormone that acts on receptors in the bed nucleus of the stria terminalis (BNST), a part of the so-called 'extended amygdala.' The amygdala and BNST send outputs to the same hypothalamic and brainstem targets to produce phasic and sustained fear, respectively. In rats, sustained fear is more sensitive to anxiolytic drugs. In humans, symptoms of clinical anxiety are better detected in sustained rather than phasic fear paradigms.