Fear conditioning and extinction in anxious and nonanxious youth and adults: examining a novel developmentally appropriate fear-conditioning task

BACKGROUND

Fear conditioning and extinction have been implicated in the pathogenesis of anxiety disorders. However, due to ethical and methodological limitations, few studies have examined these learning processes across development, particularly among anxious individuals. The present study examined differences in fear conditioning and extinction in anxious and nonanxious youth and adults using a novel task designed to be more tolerable for children than existing paradigms.

METHODS

Twenty-two anxious adults, 15 anxious youth, 30 healthy adults, and 17 healthy youth completed two discriminative fear-conditioning tasks. A well-validated task paired a woman's fearful face with a scream as the unconditioned stimulus. The novel task paired a bell with an aversive alarm as the unconditioned stimulus. Self-reported fear, skin conductance response, and fear-potentiated startle eye blink were measured.

RESULTS

Both tasks were well tolerated and elicited fear responses with moderate stability. Anxious youth and adults reported overall greater fear than healthy participants during the tasks, although no group differences occurred in discriminative fear conditioning or extinction, as assessed by self-report or physiology.

CONCLUSION

The novel bell-conditioning task is potent in eliciting fear responses but tolerable for pediatric and anxious populations. Our findings are consistent with prior studies that have shown comparable fear learning processes in anxious and nonanxious youth, but dissimilar from studies exhibiting between-group differences in extinction. Given the limited research on fear conditioning in youth, methodological issues and suggestions for future work are discussed.

Incidental threat during visuospatial working memory in adolescent anxiety: an emotional memory-guided saccade task

BACKGROUND

Pediatric anxiety disorders are among the most common psychiatric mental illnesses in children and adolescents, and are associated with abnormal cognitive control in emotional, particularly threat, contexts. In a series of studies using eye movement saccade tasks, we reported anxiety-related alterations in the interplay of inhibitory control with incentives, or with emotional distractors. The present study extends these findings to working memory (WM), and queries the interaction of spatial WM with emotional stimuli in pediatric clinical anxiety.

METHODS

Participants were 33 children/adolescents diagnosed with an anxiety disorder, and 22 age-matched healthy comparison youths. Participants completed a novel eye movement task, an affective variant of the memory-guided saccade task. This task assessed the influence of incidental threat on spatial WM processes during high and low cognitive load.

RESULTS

Healthy but not anxious children/adolescents showed slowed saccade latencies during incidental threat in low-load but not high-load WM conditions. No other group effects emerged on saccade latency or accuracy.

CONCLUSIONS

The current data suggest a differential pattern of how emotion interacts with cognitive control in healthy youth relative to anxious youth. These findings extend data from inhibitory processes, reported previously, to spatial WM in pediatric anxiety.

A neurobehavioral account for individual differences in resilience to chronic military stress

BACKGROUND

Military training is a chronic stressful period that often induces stress-related psychopathology. Stress vulnerability and resilience depend on personality trait anxiety, attentional threat bias and prefrontal-limbic dysfunction. However, how these neurobehavioral elements interact with regard to the development of symptoms following stress remains unclear.

METHOD

Fifty-five healthy combat soldiers undergoing intensive military training completed functional magnetic resonance imaging (fMRI) testing while performing the dot-probe task (DPT) composed of angry (threat) and neutral faces. Participants were then stratified according to their bias tendency to avoidance (n = 25) or vigilance (n = 30) groups, categorized as high or low trait anxiety and assessed for post-stress symptom severity.

RESULTS

Avoidance compared to vigilance tendency was associated with fewer post-trauma symptoms and increased hippocampal response to threat among high anxious but not low anxious individuals. Importantly, mediation analysis revealed that only among high anxious individuals did hippocampal activity lead to lower levels of symptoms through avoidance bias tendency. However, in the whole group, avoidance bias was modulated by the interplay between the hippocampus and the dorsal anterior cingulate cortex (dACC).

CONCLUSIONS

Our results provide a neurobehavioral model to explain the resilience to post-trauma symptoms following chronic exposure. The model points to the importance of considering threat bias tendency in addition to personality traits when investigating the brain response and symptoms of trauma. Such a multi-parametric approach that accounts for individual behavioral sensitivities may also improve brain-driven treatments of anxiety, possibly by targeting the interplay between the hippocampus and the dACC.

Attentional bias to food cues in youth with loss of control eating

Emerging data indicate that adults with binge eating may exhibit an attentional bias toward highly palatable foods, which may promote obesogenic eating patterns and excess weight gain. However, it is unknown to what extent youth with loss of control (LOC) eating display a similar bias. We therefore studied 76 youth (14.5 ± 2.3 years; 86.8% female; BMI-z 1.7 ± .73) with (n = 47) and without (n = 29) reported LOC eating. Following a breakfast to reduce hunger, youth participated in a computerized visual probe task of sustained attention that assessed reaction time to pairs of pictures consisting of high palatable foods, low palatable foods, and neutral household objects. Although sustained attentional bias did not differ by LOC eating presence and was unrelated to body weight, a two-way interaction between BMI-z and LOC eating was observed (p = .01), such that only among youth with LOC eating, attentional bias toward high palatable foods versus neutral objects was positively associated with BMI-z. These findings suggest that LOC eating and body weight interact in their association with attentional bias to highly palatable foods cues, and may partially explain the mixed literature linking attentional bias to food cues with excess body weight.

Neural activation during anticipated peer evaluation and laboratory meal intake in overweight girls with and without loss of control eating

The interpersonal model of loss of control (LOC) eating proposes that socially distressing situations lead to anxious states that trigger excessive food consumption. Self-reports support these links, but the neurobiological underpinnings of these relationships remain unclear. We therefore examined brain regions associated with anxiety in relation to LOC eating and energy intake in the laboratory. Twenty-two overweight and obese (BMIz: 1.9±0.4) adolescent (15.8±1.6y) girls with LOC eating (LOC+, n=10) and without LOC eating (LOC-, n=12) underwent functional magnetic resonance imaging (fMRI) during a simulated peer interaction chatroom paradigm. Immediately after the fMRI scan, girls consumed lunch ad libitum from a 10,934-kcal laboratory buffet meal with the instruction to "let yourself go and eat as much as you want." Pre-specified hypotheses regarding activation of five regions of interest were tested. Analysis of fMRI data revealed a significant group by peer feedback interaction in the ventromedial prefrontal cortex (vmPFC), such that LOC+ had less activity following peer rejection (vs. acceptance), while LOC- had increased activity (p<.005). Moreover, functional coupling between vmPFC and striatum for peer rejection (vs. acceptance) interacted with LOC status: coupling was positive for LOC+, but negative in LOC- (p<.005). Activity of fusiform face area (FFA) during negative peer feedback from high-value peers also interacted with LOC status (p<.005). A positive association between FFA activation and intake during the meal was observed among only those with LOC eating. In conclusion, overweight and obese girls with LOC eating may be distinguished by a failure to engage regions of prefrontal cortex implicated in emotion regulation in response to social distress. The relationship between FFA activation and food intake supports the notion that heightened sensitivity to incoming interpersonal cues and perturbations in socio-emotional neural circuits may lead to overeating in order to cope with negative affect elicited by social discomfort in susceptible youth.

Infant attachment security and early childhood behavioral inhibition interact to predict adolescent social anxiety symptoms

Insecure attachment and behavioral inhibition (BI) increase risk for internalizing problems, but few longitudinal studies have examined their interaction in predicting adolescent anxiety. This study included 165 adolescents (ages 14-17 years) selected based on their reactivity to novelty at 4 months. Infant attachment was assessed with the Strange Situation. Multimethod BI assessments were conducted across childhood. Adolescents and their parents independently reported on anxiety. The interaction of attachment and BI significantly predicted adolescent anxiety symptoms, such that BI and anxiety were only associated among adolescents with histories of insecure attachment. Exploratory analyses revealed that this effect was driven by insecure-resistant attachment and that the association between BI and social anxiety was significant only for insecure males. Clinical implications are discussed.

Aberrant amygdala intrinsic functional connectivity distinguishes youths with bipolar disorder from those with severe mood dysregulation

It remains unclear the degree to which youths with episodic mania (bipolar disorder; BD) vs. those with chronic, severe irritability (severe mood dysregulation, SMD) should be placed in similar or distinct diagnostic groups. Addressing this clinically meaningful question requires greater understanding of the neural alterations underlying both disorders. We evaluated resting state functional magnetic resonance imaging data of 53 youths (14 BD, 20 healthy volunteers (HV), and 19 SMD, ages 9-18.5 years). Seed regions of interest were the bilateral basolateral, superficial and centromedial amygdala, defined using the Juelich probabilistic atlas. We found a significant between-group difference in functional connectivity between the left basolateral amygdala and the medial aspect of the left frontal pole plus the posterior cingulate/precuneus. This finding was driven by hyperconnectivity among BD vs. HV or SMD youths. As with earlier data, these findings suggest that the pathophysiology of BD and SMD may differ.

An fMRI study of emotional face encoding in youth at risk for bipolar disorder

Face memory deficits may be a bipolar disorder (BD) endophenotype. BD (n=27) and unaffected youth at risk (n=13) exhibited middle frontal gyrus hypoactivation during successful vs. unsuccessful encoding. Parahippocampal gyrus dysfunction was found in BD and at-risk youth (vs. low-risk, n=37). Middle occipital gyrus hypoactivation was only present in BD.

Behavioral inhibition and developmental risk: a dual-processing perspective

Behavioral inhibition (BI) is an early-appearing temperament characterized by strong reactions to novelty. BI shows a good deal of stability over childhood and significantly increases the risk for later diagnosis of social anxiety disorder (SAD). Despite these general patterns, many children with high BI do not go on to develop clinical, or even subclinical, anxiety problems. Therefore, understanding the cognitive and neural bases of individual differences in developmental risk and resilience is of great importance. The present review is focused on the relation of BI to two types of information processing: automatic (novelty detection, attention biases to threat, and incentive processing) and controlled (attention shifting and inhibitory control). We propose three hypothetical models (Top-Down Model of Control; Risk Potentiation Model of Control; and Overgeneralized Control Model) linking these processes to variability in developmental outcomes for BI children. We argue that early BI is associated with an early bias to quickly and preferentially process information associated with motivationally salient cues. When this bias is strong and stable across development, the risk for SAD is increased. Later in development, children with a history of BI tend to display normative levels of performance on controlled attention tasks, but they demonstrate exaggerated neural responses in order to do so, which may further potentiate risk for anxiety-related problems. We conclude by discussing the reviewed studies with reference to the hypothetical models and make suggestions regarding future research and implications for treatment.

The neural correlates of emotional face-processing in adolescent depression: a dimensional approach focusing on anhedonia and illness severity

Deficits in emotion processing, a known clinical feature of major depressive disorder (MDD), have been widely investigated using emotional face paradigms and neuroimaging. However, most studies have not accounted for the high inter-subject variability of symptom severity. Similarly, only sparse research has focused on MDD in adolescence, early in the course of the illness. Here we sought to investigate neural responses to emotional faces using both categorical and dimensional analyses with a focus on anhedonia, a core symptom of MDD associated with poor outcomes. Nineteen medication-free depressed adolescents and 18 healthy controls (HC) were scanned during presentation of happy, sad, fearful, and neutral faces. ANCOVAs and regressions assessed group differences and relationships with illness and anhedonia severity, respectively. Findings included a group by valence interaction with depressed adolescents exhibiting decreased activity in the superior temporal gyrus (STG), putamen and premotor cortex. Post-hoc analyses confirmed decreased STG activity in MDD adolescents. Dimensional analyses revealed associations between illness severity and altered responses to negative faces in prefrontal, cingulate, striatal, and limbic regions. However, anhedonia severity was uniquely correlated with responses to happy faces in the prefrontal, cingulate, and insular regions. Our work highlights the need for studying specific symptoms dimensionally in psychiatric research.

Conduct disorder and callous-unemotional traits in youth

The term “conduct problems” refers to a pattern of repetitive rule-breaking behavior, aggression, and disregard for others. Such problems have received increased attention recently, owing to violent events perpetrated by youth and modifications in the Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria for conduct disorder, a syndrome involving recurrent conduct problems in children and adolescents. Youth conduct problems are predictive of an increased risk of substance abuse, criminal behavior, and educational disruption; they also incur a considerable societal burden from interpersonal suffering and financial costs. This review summarizes current data on youth conduct problems and highlights promising avenues for research. Prior reviews have summarized either the clinical literature on outcome, treatment, and familial aggregation or the neurocognitive literature on mechanisms and pathophysiology.^– The current review differs by more tightly integrating clinical and neurocognitive perspectives.

Oxytocin and vasopressin modulate risk-taking

The modulation of risk-taking is critical for adaptive and optimal behavior. This study examined how oxytocin (OT) and arginine vasopressin (AVP) influence risk-taking in function of three parameters: sex, risk-valence, and social context. Twenty-nine healthy adults (14 males) completed a risk-taking task, the Stunt task, both in a social-stress (evaluation by unfamiliar peers) and non-social context, in three separate drug treatment sessions. During each session, one of three drugs, OT, AVP, or placebo (PLC), was administered intra-nasally. OT and AVP relative to PLC reduced betting-rate (risk-averse effect). This risk-averse effect was further qualified: AVP reduced risk-taking in the positive risk-valence (high win-probability), and regardless of social context or sex. In contrast, OT reduced risk-taking in the negative risk-valence (low win-probability), and only in the social-stress context and men. The reduction in risk-taking might serve a role in defensive behavior. These findings extend the role of these neuromodulators to behaviors beyond the social realm. How the behavioral modulation of risk-taking maps onto the function of the neural targets of OT and AVP may be the next step in this line of research.

Parametric modulation of neural activity during face emotion processing in unaffected youth at familial risk for bipolar disorder

OBJECTIVES

Both patients with pediatric bipolar disorder (BD) and unaffected youth at familial risk (AR) for the illness show impairments in face emotion labeling. Few studies, however, have examined brain regions engaged in AR youth when processing emotional faces. Moreover, studies have yet to explore neural responsiveness to subtle changes in face emotion in AR youth.

METHODS

Sixty-four unrelated youth, including 20 patients with BD, 15 unaffected AR youth, and 29 healthy comparisons (HC), completed functional magnetic resonance imaging. Neutral faces were morphed with angry or happy faces in 25% intervals. In specific phases of the task, youth alternatively made explicit (hostility) or implicit (nose width) ratings of the faces. The slope of blood oxygenated level-dependent activity was calculated across neutral to angry and neutral to happy face stimuli.

RESULTS

Behaviorally, both subjects with BD (p ≤ 0.001) and AR youth (p ≤ 0.05) rated faces as less hostile relative to HC. Consistent with this, in response to increasing anger on the face, patients with BD and AR youth showed decreased modulation in the amygdala and inferior frontal gyrus (IFG; BA 46) compared to HC (all p ≤ 0.05). Amygdala dysfunction was present across both implicit and explicit rating conditions, but IFG modulation deficits were specific to the explicit condition. With increasing happiness, AR youth showed aberrant modulation in the IFG, which was also sensitive to task demands (all p ≤ 0.05).

CONCLUSIONS

Decreased amygdala and IFG modulation in patients with BD and AR youth may be pathophysiological risk markers for BD, and may underlie the social cognition and face emotion labeling deficits observed in BD and AR youth.

Neural changes with attention bias modification for anxiety: a randomized trial

Attention bias modification (ABM) procedures typically reduce anxiety symptoms, yet little is known about the neural changes associated with this behavioral treatment. Healthy adults with high social anxiety symptoms (n = 53) were randomized to receive either active or placebo ABM. Unlike placebo ABM, active ABM aimed to train individuals' attention away from threat. Using the dot-probe task, threat-related attention bias was measured during magnetic resonance imaging before and after acute and extended training over 4 weeks. A subset of participants completed all procedures (n = 30, 15 per group). Group differences in neural activation were identified using standard analyses. Linear regression tested predictive factors of symptom reduction (i.e., training group, baseline indices of threat bias). The active and placebo groups exhibited different patterns of right and left amygdala activation with training. Across all participants irrespective of group, individuals with greater left amygdala activation in the threat-bias contrast prior to training exhibited greater symptom reduction. After accounting for baseline amygdala activation, greater symptom reduction was associated with assignment to the active training group. Greater left amygdala activation at baseline predicted reductions in social anxiety symptoms following ABM. Further research is needed to clarify brain-behavior mechanisms associated with ABM training.

Evaluating the risks of clinical research: direct comparative analysis

OBJECTIVES

Many guidelines and regulations allow children and adolescents to be enrolled in research without the prospect of clinical benefit when it poses minimal risk. However, few systematic methods exist to determine when research risks are minimal. This situation has led to significant variation in minimal risk judgments, raising concern that some children are not being adequately protected. To address this concern, we describe a new method for implementing the widely endorsed "risks of daily life" standard for minimal risk. This standard defines research risks as minimal when they do not exceed the risks posed by daily life activities or routine examinations.

METHODS

This study employed a conceptual and normative analysis, and use of an illustrative example.

RESULTS

Different risks are composed of the same basic elements: Type, likelihood, and magnitude of harm. Hence, one can compare the risks of research and the risks of daily life by comparing the respective basic elements with each other. We use this insight to develop a systematic method, direct comparative analysis, for implementing the "risks of daily life" standard for minimal risk. The method offers a way of evaluating research procedures that pose the same types of risk as daily life activities, such as the risk of experiencing anxiety, stress, or other psychological harm. We thus illustrate how direct comparative analysis can be applied in practice by using it to evaluate whether the anxiety induced by a respiratory CO2 challenge poses minimal or greater than minimal risks in children and adolescents.

CONCLUSIONS

Direct comparative analysis is a systematic method for applying the "risks of daily life" standard for minimal risk to research procedures that pose the same types of risk as daily life activities. It thereby offers a method to protect children and adolescents in research, while ensuring that important studies are not blocked because of unwarranted concerns about research risks.

Cognitive control moderates early childhood temperament in predicting social behavior in 7-year-old children: an ERP study

Behavioral inhibition (BI) is a temperament associated with heightened vigilance and fear of novelty in early childhood, and social reticence and increased risk for anxiety problems later in development. However, not all behaviorally inhibited children develop signs of anxiety. One mechanism that might contribute to the variability in developmental trajectories is the recruitment of cognitive-control resources. The current study measured N2 activation, an ERP (event-related potential) associated with cognitive control, and modeled source-space activation (LORETA; Low Resolution Brain Electromagnetic Tomography) at 7 years of age while children performed a go/no-go task. Activation was estimated for the entire cortex and then exported for four regions of interest: ventromedial prefrontal cortex (VMPFC), ventrolateral prefrontal cortex (VLPFC), dorsal anterior cingulate cortex (dorsal ACC), and dorsal lateral prefrontal cortex (DLPFC). BI was measured in early childhood (ages 2 and 3 years). Anxiety problems and social reticence were measured at 7 years of age to ascertain stability of temperamental style. Results revealed that BI was associated with increased performance accuracy, longer reaction times, greater (more negative) N2 activation, and higher estimated dorsal ACC and DLPFC activation. Furthermore, early BI was only associated with social reticence at age 7 at higher (more negative) levels of N2 activation or higher estimated dorsal ACC or DLPFC activation. Results are discussed in the context of overcontrolled behavior contributing to social reticence and signs of anxiety in middle childhood.

Age-related changes in the intrinsic functional connectivity of the human ventral vs. dorsal striatum from childhood to middle age

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Striatal resting state iFC in 106 healthy individuals ranging from 9 to 44 years.

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Findings cohere with a dorsal–ventral functional dissociation of the striatum.

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Ventral striatal (VS) iFC with insula and anterior cingulate decreased with age.

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Dorsal striatal (DS) iFC with posterior cingulate increased with age.

The striatum codes motivated behavior. Delineating age-related differences within striatal circuitry can provide insights into neural mechanisms underlying ontogenic behavioral changes and vulnerabilities to mental disorders. To this end, a dual ventral/dorsal model of striatal function was examined using resting state intrinsic functional connectivity (iFC) imaging in 106 healthy individuals, ages 9–44. Broadly, the dorsal striatum (DS) is connected to prefrontal and parietal cortices and contributes to cognitive processes; the ventral striatum (VS) is connected to medial orbitofrontal and anterior cingulate cortices, and contributes to affective valuation and motivation. Findings revealed patterns of age-related changes that differed between VS and DS iFCs. We found an age-related increase in DS iFC with posterior cingulate cortex (pCC) that stabilized after the mid-twenties, but a decrease in VS iFC with anterior insula (aIns) and dorsal anterior cingulate cortex (dACC) that persisted into mid-adulthood. These distinct developmental trajectories of VS vs. DS iFC might underlie adolescents’ unique behavioral patterns and vulnerabilities to psychopathology, and also speaks to changes in motivational networks that extend well past 25 years old.

Evolutionarily conserved prefrontal-amygdalar dysfunction in early-life anxiety

Some individuals are endowed with a biology that renders them more reactive to novelty and potential threat. When extreme, this anxious temperament (AT) confers elevated risk for the development of anxiety, depression and substance abuse. These disorders are highly prevalent, debilitating and can be challenging to treat. The high-risk AT phenotype is expressed similarly in children and young monkeys and mechanistic work demonstrates that the central (Ce) nucleus of the amygdala is an important substrate. Although it is widely believed that the flow of information across the structural network connecting the Ce nucleus to other brain regions underlies primates' capacity for flexibly regulating anxiety, the functional architecture of this network has remained poorly understood. Here we used functional magnetic resonance imaging (fMRI) in anesthetized young monkeys and quietly resting children with anxiety disorders to identify an evolutionarily conserved pattern of functional connectivity relevant to early-life anxiety. Across primate species and levels of awareness, reduced functional connectivity between the dorsolateral prefrontal cortex, a region thought to play a central role in the control of cognition and emotion, and the Ce nucleus was associated with increased anxiety assessed outside the scanner. Importantly, high-resolution 18-fluorodeoxyglucose positron emission tomography imaging provided evidence that elevated Ce nucleus metabolism statistically mediates the association between prefrontal-amygdalar connectivity and elevated anxiety. These results provide new clues about the brain network underlying extreme early-life anxiety and set the stage for mechanistic work aimed at developing improved interventions for pediatric anxiety.

Perturbed threat monitoring following a traumatic event predicts risk for post-traumatic stress disorder

BACKGROUND

Post-traumatic stress disorder (PTSD) is a chronic and difficult to treat psychiatric disorder. Objective, performance-based diagnostic markers that uniquely index risk for PTSD above and beyond subjective self-report markers could inform attempts to improve prevention and early intervention. We evaluated the predictive value of threat-related attention bias measured immediately after a potentially traumatic event, as a risk marker for PTSD at a 3-month follow-up. We measured the predictive contribution of attentional threat bias above and beyond that of the more established marker of risk for PTSD, self-reported psychological dissociation.

METHOD

Dissociation symptoms and threat-related attention bias were measured in 577 motor vehicle accident (MVA) survivors (mean age = 35.02 years, 356 males) within 24 h of admission to an emergency department (ED) of a large urban hospital. PTSD symptoms were assessed at a 3-month follow-up using the Clinician-Administered PTSD Scale (CAPS).

RESULTS

Self-reported dissociation symptoms significantly accounted for 16% of the variance in PTSD at follow-up, and attention bias toward threat significantly accounted for an additional 4% of the variance in PTSD.

CONCLUSIONS

Threat-related attention bias can be reliably measured in the context of a hospital ED and significantly predicts risk for later PTSD. Possible mechanisms underlying the association between threat bias following a potentially traumatic event and risk for PTSD are discussed. The potential application of an attention bias modification treatment (ABMT) tailored to reduce risk for PTSD is suggested.

Attention bias to threat faces in severe mood dysregulation

BACKGROUND

We used a dot-probe paradigm to examine attention bias toward threat (i.e., angry) and happy face stimuli in severe mood dysregulation (SMD) versus healthy comparison (HC) youth. The tendency to allocate attention to threat is well established in anxiety and other disorders of negative affect. SMD is characterized by the negative affect of irritability, and longitudinal studies suggest childhood irritability predicts adult anxiety and depression. Therefore, it is important to study pathophysiologic connections between irritability and anxiety disorders.

METHODS

SMD patients (N = 74) and HC youth (N = 42) completed a visual probe paradigm to assess attention bias to emotional faces. Diagnostic interviews were conducted and measures of irritability and anxiety were obtained in patients.

RESULTS

SMD youth differed from HC youth in having a bias toward threatening faces (P < .01). Threat bias was positively correlated with the severity of the SMD syndrome and depressive symptoms; degree of threat bias did not differ between SMD youth with and without co-occurring anxiety disorders or depression. SMD and HC youth did not differ in bias toward or away from happy faces.

CONCLUSIONS

SMD youth demonstrate an attention bias toward threat, with greater threat bias associated with higher levels of SMD symptom severity. Our findings suggest that irritability may share a pathophysiological link with anxiety and depressive disorders. This finding suggests the value of exploring further whether attention bias modification treatments that are effective for anxiety are also helpful in the treatment of irritability.

Irritability in child and adolescent anxiety disorders

BACKGROUND

Our objective was to compare self- and parent-reported irritability in youths with anxiety disorders, healthy youths, and those with mood disorders characterized by irritability. Irritability is a common but relatively understudied psychiatric symptom in child and adolescent anxiety disorders. In anxious youths, little is known about the severity of irritability, its impact on functioning, or the effect of informant source on reports of irritability.

METHODS

We compared parent- and self-report forms of the Affective Reactivity Index (ARI), a validated measure of irritability, in youths ages 8-17 years with no psychopathology (healthy comparison, HC; n = 38), anxiety disorders (ANX; n = 42), bipolar disorder (BD; n = 35), or severe mood dysregulation (SMD; n = 61; a phenotype characterized by chronic, severely impairing irritability).

RESULTS

Irritability was significantly higher in ANX than HC youths by both parent and self-report (partial η(2) = 0.24 and 0.22, respectively, P's < 0.001). Informant effects differed among ANX, BD, and SMD. Overall, parent-reported irritability was higher in BD with comorbid anxiety disorders and SMD with or without comorbid anxiety disorders than ANX (P's < 0.007), but self-reported irritability was not significantly different among the three patient groups.

DISCUSSION

By both parent and self-report, youths with anxiety disorders exhibit significantly more irritability and associated impairment than healthy subjects. Self-reported irritability in youths with anxiety disorders is comparable to that observed in youths with severe mood disorders, although parental reports of irritability differ among the disorders. Future research should examine the pathophysiology of anxiety-associated irritability, as well as its prognostic and treatment implications.

Generalized anxiety disorder is associated with overgeneralization of classically conditioned fear

BACKGROUND

Meta-analytic results of fear-conditioning studies in the anxiety disorders implicate generalization of conditioned fear to stimuli resembling the conditioned danger cue as one of the more robust conditioning markers of anxiety pathology. Due to the absence of conditioning studies assessing generalization in generalized anxiety disorder (GAD), results of this meta-analysis do not reveal whether such generalization abnormalities also apply to GAD. The current study fills this gap by behaviorally and psychophysiologically assessing levels of conditioned fear generalization across adults with and without GAD.

METHODS

Twenty-two patients with a DSM-IV-Text Revision diagnosis of GAD and 26 healthy comparison subjects were recruited and tested. The employed generalization paradigm consisted of quasi-randomly presented rings of gradually increasing size, with extreme sizes serving as conditioned danger cues (CS+) and conditioned safety cues. The rings of intermediary size served as generalization stimuli, creating a continuum of similarity between CS+ and conditioned safety cues across which to assess response slopes, referred to as generalization gradients. Primary outcome variables included slopes for fear-potentiated startle (electromyography) and self-reported risk ratings.

RESULTS

Behavioral and psychophysiological findings demonstrated overgeneralization of conditioned fear among patients with GAD. Specifically, generalization gradients were abnormally shallow among GAD patients, reflecting less degradation of the conditioned fear response as the presented stimulus differentiated from the CS+.

CONCLUSIONS

Overgeneralization of conditioned fear to safe encounters resembling feared situations may contribute importantly to the psychopathology of GAD by proliferating anxiety cues in the individual's environment that are then capable of evoking and maintaining anxiety and worry associated with GAD.

Identification of emotional facial expressions among behaviorally inhibited adolescents with lifetime anxiety disorders

The current study examined differences in emotion expression identification between adolescents characterised with behavioural inhibition (BI) in childhood with and without a lifetime history of anxiety disorder. Participants were originally assessed for BI during toddlerhood and for social reticence during childhood. During adolescence, participants returned to the laboratory and completed a facial emotion identification task and a clinical psychiatric interview. Results revealed that behaviorally inhibited adolescents with a lifetime history of anxiety disorder displayed a lower threshold for identifying fear relative to anger emotion expressions compared to non-anxious behaviorally inhibited adolescents and non-inhibited adolescents with or without anxiety. These findings were specific to behaviorally inhibited adolescents with a lifetime history of social anxiety disorder. Thus, adolescents with a history of both BI and anxiety, specifically social anxiety, are more likely to differ from other adolescents in their identification of fearful facial expressions. This offers further evidence that perturbations in the processing of emotional stimuli may underlie the aetiology of anxiety disorders.