Shared and Anxiety-Specific Pediatric Psychopathology Dimensions Manifest Distributed Neural Correlates

BACKGROUND

Imaging research has not yet delivered reliable psychiatric biomarkers. One challenge, particularly among youth, is high comorbidity. This challenge might be met through canonical correlation analysis designed to model mutual dependencies between symptom dimensions and neural measures. We mapped the multivariate associations that intrinsic functional connectivity manifests with pediatric symptoms of anxiety, irritability, and attention-deficit/hyperactivity disorder (ADHD) as common, impactful, co-occurring problems. We evaluate the replicability of such latent dimensions in an independent sample.

METHODS

We obtained ratings of anxiety, irritability, and ADHD, and 10 minutes of resting-state functional magnetic resonance imaging data, from two independent cohorts. Both cohorts (discovery: n = 182; replication: n = 326) included treatment-seeking youth with anxiety disorders, with disruptive mood dysregulation disorder, with ADHD, or without psychopathology. Functional connectivity was modeled as partial correlations among 216 brain areas. Using canonical correlation analysis and independent component analysis jointly we sought maximally correlated, maximally interpretable latent dimensions of brain connectivity and clinical symptoms.

RESULTS

We identified seven canonical variates in the discovery and five in the replication cohort. Of these canonical variates, three exhibited similarities across datasets: two variates consistently captured shared aspects of irritability, ADHD, and anxiety, while the third was specific to anxiety. Across cohorts, canonical variates did not relate to specific resting-state networks but comprised edges interconnecting established networks within and across both hemispheres.

CONCLUSIONS

Findings revealed two replicable types of clinical variates, one related to multiple symptom dimensions and a second relatively specific to anxiety. Both types involved a multitude of broadly distributed, weak brain connections as opposed to strong connections encompassing known resting-state networks.

Across-subjects multiple baseline trial of exposure-based cognitive-behavioral therapy for severe irritability: a study protocol

INTRODUCTION

Irritability is defined as a tendency towards anger in response to frustration. Clinically, impairing irritability is a significant public health problem. There is a need for mechanism-based psychotherapies targeting severe irritability as it manifests in the context of disruptive mood dysregulation disorder (DMDD). This study protocol describes a randomised multiple baseline design testing the preliminary efficacy of a new treatment, exposure-based cognitive-behavioral therapy for severe irritability in youth, which also integrates components of parent management training. We will investigate associations of this intervention with primary clinical measures, as well as ecological momentary assessment measures.

METHODS AND ANALYSIS

Forty youth will be enrolled. Participants, aged 8-17 years, must present at least one of two core symptoms of DMDD: abnormal mood or increased reactivity to negative emotional stimuli, with severe impairment in one domain (home, school, peers) and moderate in another, or moderate impairment in at least two domains. Each participant is randomised to a 2-week, 4-week or 6-week baseline observation period, followed by 12 active treatment sessions. Clinical ratings are conducted at baseline, biweekly (clinician), weekly (parent/child) throughout treatment, post-treatment, and 3-month and 6-month follow-up (clinician). Clinician ratings on the Affective Reactivity Index and Clinical Global Impressions-Improvement scale for DMDD are our primary outcome measures. Secondary outcome measures include parent and child reports of irritability. Post hoc additional symptom measures include clinician, parent and self-ratings of depression, anxiety and overall functional impairment. Prospective, digitally based event sampling of symptoms is acquired for a week pre-treatment, mid-treatment and post-treatment. Based on our pathophysiological model of irritability implicating frustrative non-reward, aberrant threat processing and instrumental learning, we probe these three brain-based targets using functional MRI paradigms to assess target engagement.

ETHICS AND DISSEMINATION

The research project and all related materials were submitted and approved by the appropriate Institutional Review Board (IRB) of the National Institute of Mental Health (NIMH).

TRIAL REGISTRATION NUMBERS

NCT02531893 and NCT00025935.

Toward a Developmental Nosology for Disruptive Mood Dysregulation Disorder in Early Childhood

OBJECTIVE

Disruptive mood dysregulation disorder (DMDD) in DSM, characterized by severe, chronic irritability, currently excludes children <6 years of age. However, capitalizing on a burgeoning developmental science base to differentiate clinically salient irritability in young children may enable earlier identification. The objective of this study was to advance an empirically derived framework for early childhood DMDD (EC-DMDD) by modeling and validating DMDD patterns in early childhood and generating clinically informative, optimized behaviors with thresholds.

METHOD

Data (N = 425) were from 3 longitudinal assessments of the MAPS Study, spanning preschool (means = 4.7 and 5.5 years) to early school age (mean = 6.8 years). The Multidimensional Assessment Profile of Disruptive Behavior (MAP-DB) Temper Loss scale captured irritability, the Family Life Impairment Scale (FLIS) assessed cross-domain impairment at the preschool time points and the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS) was used to assess clinical status at early school age. Latent transition analyses differentiated children with EC-DMDD from children with low, transient, or nonimpairing irritability.

RESULTS

Developmental patterning of irritability proved important for normal:abnormal differentiation. Of children, 27% had initially high irritability, but only two-thirds of these were persistently highly irritable. Thus, "false positives" based on a single screen would be substantial. Yet, "false negatives" are low, as <1% of children with baseline low irritability demonstrated later high irritability. Based on the sequential preschool-age time points, 6.7% of children were identified with EC-DMDD, characterized by persistent irritability with pervasive impairment, similar to prevalence at older ages. Specific behaviors included low frustration tolerance; dysregulated, developmentally unexpectable tantrums; and sustained irritable mood, all of which sensitively (0.85-0.96) and specifically (0.80-0.91) identified EC-DMDD. EC-DMDD predicted irritability-related syndromes (DMDD, oppositional defiant disorder) at early school age better than downward extension of DSM DMDD criteria to preschool age.

CONCLUSION

These findings provide empirical thresholds for preschool-age clinical identification of DMDD patterns. The results lay the foundation for validation of DMDD in early childhood and inform revision of DSM criteria.

Differentiating irritable mood and disruptive behavior in adults

Introduction

Irritability has both mood and behavioral manifestations. These frequently co-occur, and it is unclear to what extent they are dissociable domains. We used confirmatory factor analysis and external validators to investigate the independence of mood and behavioral components of irritability.

Methods

The sample comprised 246 patients (mean age 45 years; 63% female) from four outpatient programs (depression, anxiety, bipolar, and schizophrenia) at a tertiary hospital. A clinical instrument rated by trained clinicians was specifically designed to capture irritable mood and disruptive behavior dimensionally, as well as current categorical diagnoses i.e., intermittent explosive disorder (IED); oppositional defiant disorder (ODD); and an adaptation to diagnose disruptive mood dysregulation disorder (DMDD) in adults. Confirmatory factor analysis (CFA) was used to test the best fitting irritability models and regression analyses were used to investigate associations with external validators.

Results

Irritable mood and disruptive behavior were both frequent, but diagnoses of disruptive syndromes were rare (IED, 8%; ODD, 2%; DMDD, 2%). A correlated model with two dimensions, and a bifactor model with one general dimension and two specific dimensions (mood and behavior) both had good fit indices. The correlated model had root mean square error of approximation (RMSEA) = 0.077, with 90% confidence interval (90%CI) = 0.071-0.083; comparative fit index (CFI) = 0.99; and Tucker-Lewis index (TLI) = 0.99, while the bifactor model had RMSEA = 0.041; CFI = 0.99; and TLI = 0.99 respectively). In the bifactor model, external validity for differentiation of the mood and behavioral components of irritability was also supported by associations between irritable mood and impairment and clinical measures of depression and mania, which were not associated with disruptive behavior.

Conclusions

Psychometric and external validity data suggest both overlapping and specific features of the mood vs. disruptive behavior dimensions of irritability.

Emotional distractors and attentional control in anxious youth: eye tracking and fMRI data

Attentional control theory suggests that high cognitive demands impair the flexible deployment of attention control in anxious adults, particularly when paired with external threats. Extending this work to pediatric anxiety, we report two studies utilising eye tracking (Study 1) and functional magnetic resonance imaging (Study 2). Both studies use a visual search paradigm to examine anxiety-related differences in the impact of threat on attentional control at varying levels of task difficulty. In Study 1, youth ages 8-18 years (N = 109), completed the paradigm during eye tracking. Results indicated that youth with more severe anxiety took longer to fixate on and identify the target, specifically on difficult trials, compared to youth with less anxiety. However, no anxiety-related effects of emotional distraction (faces) emerged. In Study 2, a separate cohort of 8-18-year-olds (N = 72) completed a similar paradigm during fMRI. Behaviourally, youth with more severe anxiety were slower to respond on searches following non-threatening, compared to threatening, distractors, but this effect did not vary by task difficulty. The same interaction emerged in the neuroimaging analysis in the superior parietal lobule and precentral gyrus-more severe anxiety was associated with greater brain response following non-threatening distractors. Theoretical implications of these inconsistent findings are discussed.

Genetic and environmental risk structure of internalizing psychopathology in youth

BACKGROUND

Internalizing disorders (IDs), consisting of syndromes of anxiety and depression, are common, debilitating conditions often beginning early in life. Various trait-like psychological constructs are associated with IDs. Our prior analysis identified a tripartite model of Fear/Anxiety, Dysphoria, and Positive Affect among symptoms of anxiety and depression and the following constructs in youth: anxiety sensitivity, fearfulness, behavioral activation and inhibition, irritability, neuroticism, and extraversion. The current study sought to elucidate their overarching latent genetic and environmental risk structure.

METHODS

The sample consisted of 768 juvenile twin subjects ages 9-14 assessed for the nine, abovementioned measures. We compared two multivariate twin models of this broad array of phenotypes.

RESULTS

A hypothesis-driven, common pathway twin model reflecting the tripartite structure of the measures were fit to these data. However, an alternative independent pathway model provided both a better fit and more nuanced insights into their underlying genetic and environmental risk factors.

CONCLUSIONS

Our findings suggest a complex latent genetic and environmental structure to ID phenotypes in youth. This structure, which incorporates both clinical symptoms and various psychological traits, informs future phenotypic approaches for identifying specific genetic and pathophysiological mechanisms underlying ID risk.

Self-Efficacy As a Target for Neuroscience Research on Moderators of Treatment Outcomes in Pediatric Anxiety

Objective: Despite the advances in the field of neuroscience, many questions remain regarding the mechanisms of anxiety, as well as moderators of treatment outcome. Long-term adverse outcomes for anxious youth may relate to pathophysiologically based information processing patterns and self-referential beliefs, such as self-efficacy. In fact, there are no studies highlighting the relationship between self-efficacy and neurocircuitry in youth. The purpose of this study was to explore the relationships between self-efficacy, brain morphometry, and youth anxiety. Methods: Parent, child, and clinician ratings of anxiety symptoms and child-reported self-efficacy were analyzed in a sample of 8- to 17-year-old youth (n = 51). Measures were collected from all youth at baseline and during and after treatment for the patients. Anxious patients (n = 26) received 12 sessions of cognitive behavioral therapy (CBT). Moreover, imaging data obtained from all participants before treatment were utilized in analyses. Results: Patients reported lower self-efficacy than healthy volunteers. Across the entire sample, anxiety was negatively related to total, social, and emotional efficacy. Both social and emotional efficacy predicted anxiety posttreatment. In addition, social efficacy predicted social anxiety symptoms posttreatment and social efficacy increased across treatment. There were no significant relations between self-efficacy and neurocircuitry. Conclusions: Self-efficacy is an important treatment target for anxious youth. Although self-efficacy was not related to brain morphometry, self-efficacy beliefs may constitute an important mechanism through which CBT and psychopharmacological interventions decrease fear and anxiety symptoms in youth.

A Double-Blind Randomized Placebo-Controlled Trial of Citalopram Adjunctive to Stimulant Medication in Youth With Chronic Severe Irritability

OBJECTIVE

Despite the clinical importance of chronic and severe irritability, there is a paucity of controlled trials for its pharmacological treatment. Here, we examine the effects of adding citalopram (CTP) to methylphenidate (MPH) in the treatment of chronic severe irritability in youth using a double-blind randomized placebo-controlled design.

METHOD

After a lead-in phase of open treatment with stimulant, 53 youth meeting criteria for severe mood dysregulation (SMD) were randomly assigned to receive CTP or placebo (PBO) for 8 weeks. A total of 49 participants, 48 of them (98%) meeting disruptive mood dysregulation disorder (DMDD) criteria, were included in the intent-to-treat analysis. The primary outcome measure was the proportion of response based on improvements of irritability at the week 8 of the trial.

RESULTS

At the end of the trial, a significantly higher proportion of response was seen in those participants randomly assigned to CTP+MPH compared to PBO+MPH (35% CTP+MPH versus 6% PBO+MPH; odds ratio = 11.70, 95% CI = 2.00-68.16, p = 0.006). However, there were no differences in functional impairment between groups at the end of the trial. No differences were found in any adverse effect between treatment groups, and no trial participant exhibited hypomanic or manic symptoms.

CONCLUSION

Adjunctive CTP might be efficacious in the treatment of chronic severe irritability in youth resistant to stimulant treatment alone.

CLINICAL TRIAL REGISTRATION INFORMATION

A Controlled Trial of Serotonin Reuptake Inhibitors Added to Stimulant Medication in Youth With Severe Mood Dysregulation; https://clinicaltrials.gov; NCT00794040.

The Clinician Affective Reactivity Index: Validity and Reliability of a Clinician-Rated Assessment of Irritability

Irritability is impairing in youth and is the core feature of disruptive mood dysregulation disorder (DMDD). Currently, there are no established clinician-rated instruments to assess irritability in pediatric research and clinical settings. Clinician-rated measures ensure consistency of assessment across patients and are important specifically for treatment research. Here, we present data on the psychometric properties of the Clinician Affective Reactivity Index (CL-ARI), the first semistructured interview focused on pediatric irritability. The CL-ARI was administered to a transdiagnostic sample of 98 youth (M age = 12.66, SD = 2.47; 41% female). With respect to convergent validity, CL-ARI scores were (a) significantly higher for youth with DMDD than for any other diagnostic group, and (b) showed uniquely strong associations with other clinician-, parent-, and youth-report measures of irritability compared to measures of related constructs, such as anxiety. The three subscales of the CL-ARI (temper outbursts, irritable mood, impairment) showed excellent internal consistency. Test-retest reliability of the CL-ARI was adequate. These data support that irritability can be feasibly, validly, and reliably assessed by clinicians using the CL-ARI. A validated, gold-standard assessment of pediatric irritability is critical in advancing research and treatment efforts.

Anxious-Irritable Children: A Distinct Subtype of Childhood Anxiety?

Children with anxiety disorders often present with other co-occurring symptom clusters, of which irritability is among the most highly co-occurring. Despite compelling clinical and pathophysiological evidence linking anxiety and irritability, little is known regarding the clinical presentation and associated impairment of children with both anxiety and irritability. In this study, our aims were to confirm the preponderance of irritability in clinically anxious children and compare clinically anxious children with irritability to those without irritability across sociodemographic, clinical, psychosocial, and family domains. Participants were 230 children with anxiety disorders (ages 6-14 years) and their mothers, and 91 healthy controls (ages 6-17 years) and their mothers. Of the clinically anxious children, 121 were anxious and irritable; 109 were anxious but not irritable. Irritability levels were significantly higher in the clinically anxious children compared with the healthy controls. Children with anxiety disorders and irritability presented with greater severity and impairment across clinical phenomenology, psychosocial, and family domains relative to anxious children without irritability. Regression analysis findings were convergent in that greater severity and impairment across these same domains predicted higher irritability levels in the children with anxiety disorders. Results support the meaningful distinction between anxious children with and without irritability. Implications of the findings are discussed particularly in regard to assessment and treatment and future research directions are delineated.

White matter microstructure in youth with and at risk for bipolar disorder

OBJECTIVES

Bipolar disorder (BD) and familial risk for BD have been associated with aberrant white matter (WM) microstructure in the corpus callosum and fronto-limbic pathways. These abnormalities might constitute trait or state marker and have been suggested to result from aberrant maturation and to relate to difficulties in emotion regulation.

METHODS

To determine whether WM alterations represent a trait, disease or resilience marker, we compared youth at risk for BD (n = 36 first-degree relatives, REL) to youth with BD (n = 36) and healthy volunteers (n = 36, HV) using diffusion tensor imaging.

RESULTS

Individuals with BD and REL did not differ from each other in WM microstructure and, compared to HV, showed similar aberrations in the superior corona radiata (SCR)/corticospinal tract (CST) and the body of the corpus callosum. WM microstructure of the anterior CC showed reduced age-related in-creases in BD compared to REL and HV. Further, individuals with BD and REL showed in-creased difficulties in emotion regulation, which were associated with the microstructure of the anterior thalamic radiation.

DISCUSSION

Alterations in the SCR/CST and the body of the corpus callosum appear to represent a trait marker of BD, whereas changes in other WM tracts seem to be a disease state marker. Our findings also support the role of aberrant developmental trajectories of WM microstructure in the risk architecture of BD, although longitudinal studies are needed to confirm this association. Finally, our findings show the relevance of WM microstructure for difficulties in emotion regulation-a core characteristic of BD.

Exposure-Based Cognitive-Behavioral Therapy for Disruptive Mood Dysregulation Disorder: An Evidence-Based Case Study

Severe, chronic irritability is one of the most frequently reported problems in youth referred for psychiatric care. Irritability predicts adult depressive and anxiety disorders, and long-term impairment. Reflecting this pressing public health need, severe, chronic, and impairing irritability is now codified by the DSM-5 diagnosis of disruptive mood dysregulation disorder (DMDD). Since DMDD has only recently been added as its own nosological class, efficacious treatments that specifically target severe irritability as it presents in DMDD are still being developed. In a recent pilot study, we described the general concept of exposure-based cognitive-behavioral therapy (CBT) for irritability. This mechanism-driven treatment is based on our pathophysiological model of irritability that postulates two underlying mechanisms, which potentiate each other: (1) heightened reactivity to frustrative nonreward, and (2) aberrant approach responses to threat. In this case report, we describe and illustrate the specific therapeutic techniques used to address severe irritability in an 11-year-old boy with a primary diagnosis of DMDD. Specific techniques within this CBT include motivational interviewing to build commitment and target oppositionality; creation of an anger hierarchy; in-session controlled, gradual exposure; and parent training focusing on contingency management to counteract the instrumental learning deficits in irritable youth. Parents learn to tolerate their own emotional responses to their youth's irritability (e.g., parents engage in their own exposure) and increase their adaptive contingencies for their youth's behavior (e.g., withdraw attention during unwanted behavior, praise desirable behavior). Future directions in the context of this CBT, such as leveraging technology, computational modeling, and pathophysiological targets, are discussed.

Combining fMRI during resting state and an attention bias task in children

Neuroimaging studies typically focus on either resting state or task-based fMRI data. Prior research has shown that similarity in functional connectivity between rest and cognitive tasks, interpreted as reconfiguration efficiency, is related to task performance and IQ. Here, we extend this approach from adults to children, and from cognitive tasks to a threat-based attention task. The goal of the current study was to examine whether similarity in functional connectivity during rest and an attention bias task relates to threat bias, IQ, anxiety symptoms, and social reticence. fMRI was measured during resting state and during the dot-probe task in 41 children (M = 13.44, SD = 0.70). Functional connectivity during rest and dot-probe was positively correlated, suggesting that functional hierarchies in the brain are stable. Similarity in functional connectivity between rest and the dot-probe task only related to threat bias (puncorr < .03). This effect did not survive correction for multiple testing. Overall, children who allocate more attention towards threat also may possess greater reconfiguration efficiency in switching from intrinsic to threat-related attention states. Finally, functional connectivity correlated negatively across the two conditions of the dot-probe task. Opposing patterns of modulation of functional connectivity by threat-congruent and threat-incongruent trials may reflect task-specific network changes during two different attentional processes.

Heritability, stability, and prevalence of tonic and phasic irritability as indicators of disruptive mood dysregulation disorder

BACKGROUND

Little is known about genetic and environmental influences on the components of disruptive mood dysregulation disorder (DMDD), tonic irritability (i.e., irritable mood) and phasic irritability (i.e., temper outbursts). This study examined prevalence, stability, and heritability of tonic irritability, phasic irritability, and a DMDD proxy (pDMDD) based on DSM-5 criteria.

METHODS

pDMDD was derived using data from clinical interviews of parents and their twins (N = 1,431 twin pairs), ages 8-17, participating in Waves 1 and 2 of the Virginia Twin Study of Adolescent Behavioral Development. Biometrical modeling was used to compare a common pathway model (CPM) and an independent pathway model (IPM), and heritability estimates were obtained for pDMDD using the symptoms of irritable mood (tonic irritability; DMDD Criterion D), intense temper outbursts (phasic irritability; DMDD Criterion A), and frequent temper outbursts (phasic irritability; DMDD Criterion C).

RESULTS

Lifetime prevalence of pDMDD was 7.46%. The stability of DMDD symptoms and the pDMDD phenotype across approximately one year were moderate (.30-.69). A CPM was a better fit to the data than an IPM. Phasic irritability loaded strongly onto the pDMDD latent factor (.89-.96) whereas tonic irritability did not (.28). Genetic influences accounted for approximately 59% of the variance in the latent pDMDD phenotype, with the remaining 41% of the variance due to unique environmental effects. The heritability of tonic irritability (54%) was slightly lower than that of frequent and intense temper (components of phasic irritability; 61% and 63%, respectively).

CONCLUSIONS

Compared to tonic irritability, phasic irritability appears to be slightly more stable and heritable, as well as a stronger indicator of the latent factor. Furthermore, environmental experiences appear to play a substantial role in the development of irritability and DMDD, and researchers should seek to elucidate these mechanisms in future work.

Efficacy and mechanisms underlying a gamified attention bias modification training in anxious youth: protocol for a randomized controlled trial

BACKGROUND

Attention bias modification training (ABMT) and cognitive behavioral therapy (CBT) likely target different aspects of aberrant threat responses in anxiety disorders and may be combined to maximize therapeutic benefit. However, studies investigating the effect of ABMT in the context of CBT have yielded mixed results. Here, we propose an enhanced ABMT to target the attentional bias towards threat, in addition to classic CBT for anxiety disorders in youth. This enhanced ABMT integrates the modified dot-probe task used in previous studies, where a target is always presented at the previous location of the neutral and not the simultaneously presented threatening stimulus, with a visual search, where the targets are always presented distally of threatening distractors. These two training elements (modified dot-probe and visual search) are embedded in an engaging game to foster motivation and adherence. Our goal is to determine the efficacy of the enhanced ABMT in the context of CBT. Further, we aim to replicate two previous findings: (a) aberrant amygdala connectivity being the neurobiological correlate of the attentional bias towards threat at baseline; and (b) amygdala connectivity being a mediator of the ABMT effect. We will also explore moderators of treatment response (age, sex, depressive symptoms and irritability) on a behavioral and neuronal level.

METHODS

One hundred and twenty youth (8-17 years old) with a primary anxiety disorder diagnosis all receive CBT and are randomized to nine weeks of either active or control ABMT and symptom improvement will be compared between the two study arms. We will also recruit 60 healthy comparison youth, who along with eligible anxious youth, will be assessed with the dot-probe task during fMRI (anxious youth: before and after training; healthy volunteers: second measurement twelve weeks after initial assessment).

DISCUSSION

The present study will contribute to the literature by (1) potentially replicating that aberrant amygdala connectivity mediates the attentional bias towards threat in anxious youth; (2) determining the efficacy of enhanced ABMT; and (3) advancing our understanding of the mechanisms underlying ABMT.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT03283930 Trial registration date: September 14th 2017. The trial registration took place retrospectively. Data acquisition started February 1st 2017.

Advancing clinical neuroscience through enhanced tools: Pediatric social anxiety as an example

BACKGROUND

Clinical researchers face challenges when trying to quantify diverse processes engaged during social interactions. We report results from two studies, each demonstrating the potential utility of tools for examining processes engaged during social interactions.

METHOD

In the first study, youth (n = 57) used a smartphone-based tool to rate mood and responses to social events. A subset (n = 20) completed the second, functional magnetic resonance imaging study. This second study related anxiety to error-evoked brain responses in two social conditions-while being observed and when alone. We also combined these tools to bridge clinical, social-contextual, and neural levels of measurement.

RESULTS

Results from the first study showed an association between negatively-perceived social experiences and a range of negative emotions. In the second study there was a positive correlation during error monitoring between social-anxiety severity and context-specific activation of the pregenual anterior cingulate cortex. Finally, during imaging, the perceived quality of peer interactions as assessed using the smartphone-based tool, interacted with social context to predict levels of activation in the hippocampus and superior frontal gyrus.

CONCLUSIONS

By improving measurement, enhanced tools may provide new means for studying relationships among anxiety, brain function, and social interactions.

Exposure therapy for pediatric irritability: Theory and potential mechanisms

Pediatric irritability is prevalent and impairing, yet little is known about its pathophysiology and treatment. In this article, we build on our and others' previous work to posit core mechanisms of irritability operating across the brain, behavior, and environment. Specifically, we propose proximal processes that surround the symptomatology of irritability and are potential targets for an exposure-based cognitive-behavioral therapy (CBT) for irritability that our group has developed. The heart of this model focuses on neurocognitive processes: youth's encoding of nonreward and threat stimuli, which involves prediction error signaling in the brain, and cognitive control in the context of frustration. Alterations in these processes are theorized to be central to chronic, severe irritability. Environmental responses to youth's symptom expression are also examined. Exposure-based CBT for irritability utilizes controlled, in vivo exposure to nonreward and threat stimuli with the aim to engage cognitive control and target top-down regulation of frustration. This intervention integrates selected parent management training techniques to target symptom reinforcement processes. Continued pathophysiological and treatment studies of irritability will not only refine our emerging understanding of the phenotype, but also inform broader questions on the brain and behavioral mechanisms of CBT efficacy.

Genetic underpinnings of callous-unemotional traits and emotion recognition in children, adolescents, and emerging adults

BACKGROUND

Callous-Unemotional (CU) and psychopathic traits are consistently associated with impaired recognition of others' emotions, specifically fear and sadness. However, no studies have examined whether the association between CU traits and emotion recognition deficits is due primarily to genetic or environmental factors.

METHODS

The current study used data from 607 Caucasian twin pairs (N = 1,214 twins) to examine the phenotypic and genetic relationship between the Inventory of Callous-Unemotional Traits (ICU) and facial emotion recognition assessed via the laboratory-based Facial Expression Labeling Task (FELT).

RESULTS

The uncaring/callous dimension of the ICU was significantly associated with impaired recognition of happiness, sadness, fear, surprise, and disgust. The unemotional ICU dimension was significantly associated with improved recognition of surprise and disgust. Total ICU score was significantly associated with impaired recognition of sadness. Significant genetic correlations were found for uncaring/callous traits and distress cue recognition (i.e. fear and sadness). The observed relationship between uncaring/callous traits and deficits in distress cue recognition was accounted for entirely by shared genetic influences.

CONCLUSIONS

The results of the current study replicate previous findings demonstrating impaired emotion recognition among youth with elevated CU traits. We extend these findings by replicating them in an epidemiological sample not selected or enriched for pathological levels of CU traits. Furthermore, the current study is the first to investigate the genetic and environmental etiology of CU traits and emotion recognition, and results suggest genetic influences underlie the specific relationship between uncaring/callous traits and distress cue (fear/sadness) recognition in others.

Neural mechanisms of face emotion processing in youths and adults with bipolar disorder

OBJECTIVES

Little is known about potential differences in the pathophysiology of bipolar disorder (BD) across development. The present study aimed to characterize age-related neural mechanisms of BD.

METHODS

Youths and adults with and without BD (N = 108, age range = 9.8-55.9 years) completed an emotional face labeling task during fMRI acquisition. We leveraged three different fMRI analytic tools to identify age-related neural mechanisms of BD, investigating (a) change in neural responses over the course of the task, (b) neural activation averaged across the entire task, and (c) amygdala functional connectivity.

RESULTS

We found converging Age Group × Diagnosis patterns across all three analytic methods. Compared to healthy youths vs adults, youths vs adults with BD show an altered pattern in response to repeated presentation of emotional faces in medial prefrontal, amygdala, and temporoparietal regions, as well as amygdala-temporoparietal connectivity. Specifically, medial prefrontal and lingual activation decreases over the course of repeated emotional face presentations in healthy youths vs adults but increases in youths with BD compared to adults with BD. Moreover, youths vs adults with BD show less medial prefrontal activation and amygdala-temporoparietal junction connectivity averaged over the task, but this difference is not found for healthy youths vs adults.

CONCLUSION

Although longitudinal confirmation and replication will be necessary, these findings suggest that neural development may be aberrant in BD and that some neural mechanisms mediating BD may differ in adults vs children with the illness.

The genetic and environmental structure of fear and anxiety in juvenile twins

Fear and anxiety are conceptualized as responses to acute or potential threat, respectively. Adult twin studies found substantial interplay between genetic and environmental factors influencing fear disorders (phobias) and anxiety disorders. Research in children, however, has largely examined these factors independently. Thus, there exists a substantial knowledge gap regarding the underlying etiologic structure of these closely-related constructs during development. Symptom counts for five fear (criticism, the unknown, death, animal, medical) and four anxiety (generalized, panic, separation, social) dimensions were obtained for 373 twin pairs ages 9-14. Multivariate twin modeling was performed to elucidate the genetic and environmental influences distributed amongst these dimensions. The best fitting model contained one genetic, two familial environmental, and two unique environmental factors shared between fear and anxiety symptoms plus dimension-specific genetic and unique environmental factors. Although several environmental factors were shared between fear and anxiety dimensions, one latent factor accounted for genetic influences across both domains. While adult studies find somewhat distinct etiological differences between anxiety and phobic disorders, the current results suggest that their relative genetic and environmental influences are not as clearly demarcated in children. These etiological distinctions are more nuanced, likely contributing to the highly diffuse symptom patterns seen during development.

Temporally sensitive neural measures of inhibition in preschool children across a spectrum of irritability

Irritability is a prominent feature of chronic mental disorders and a developmental marker of their early emergence. The most salient feature of irritability in early childhood is temper tantrums. While temper tantrums are normative in young children, they can be clinically concerning when they are dysregulated, very frequent, and/or occur in unexpected contexts. The present study uses behavioral and event-related brain potential (ERP) measures to characterize the relationship between irritability and neural markers of response inhibition in very young children. Forty-six children (ages 4-7 years) completed a go/no-go task under nonfrustrating and frustrating conditions. ERPs elicited by go and no-go stimuli were examined as a function of frustration condition and irritability, operationalized via the well-validated Temper Loss scale of the Multidimensional Assessment Profile of Disruptive Behavior (MAP-DB). Higher Temper Loss scores were associated with larger N2no-go amplitudes and reduced no-go accuracy during frustration. This suggests that higher levels of irritability corresponded with increased conflict monitoring and poorer task performance during frustration. These findings add to a developing literature identifying the neurocognitive markers of varying levels of irritability in young children.

Fear-potentiated startle response as an endophenotype: Evaluating metrics and methods for genetic applications

The modulation of the startle response (SR) by threatening stimuli (fear-potentiated startle; FPS) is a proposed endophenotype for disorders of the fearful-fearlessness spectrum. FPS has failed to show evidence of heritability, raising concerns. However, metrics used to index FPS-and, importantly, other conditional phenotypes that are dependent on a baseline-may not be suitable for the approaches used in genetic epidemiology studies. Here, we evaluated multiple metrics of FPS in a population-based sample of preadolescent twins (N = 569 from 320 twin pairs, M_age = 11.4) who completed a fear-conditioning paradigm with airpuff-elicited SR on two occasions (~1 month apart). We applied univariate and multivariate biometric modeling to estimate the heritability of FPS using several proposed standardization procedures. This was extended with data simulations to evaluate biases in heritability estimates of FPS (and similar metrics) under various scenarios. Consistent with previous studies, results indicated moderate test-retest reliability (r = 0.59) and heritability of the overall SR (h² = 34%) but poor reliability and virtually no unique genetic influences on FPS when considering a raw or standardized differential score that removes baseline SR. Simulations demonstrated that the use of differential scores introduces bias in heritability estimates relative to jointly analyzing baseline SR and FPS in a multivariate model. However, strong dependency of FPS on baseline levels makes unique genetic influences virtually impossible to detect regardless of methodology. These findings indicate that FPS and other conditional phenotypes may not be well suited to serve as endophenotypes unless such codependency can be disentangled.

Brain Mechanisms of Attention Orienting Following Frustration: Associations With Irritability and Age in Youths

OBJECTIVE

Childhood irritability is a common, impairing problem with changing age-related manifestations that predict long-term adverse outcomes. However, more investigation of overall and age-specific neural correlates is needed. Because youths with irritability exhibit exaggerated responses to frustrating stimuli, the authors used a frustration functional MRI (fMRI) paradigm to examine associations between irritability and neural activation and tested the moderating effect of age.

METHOD

The authors studied a transdiagnostic sample of 195 youths with varying levels of irritability (disruptive mood dysregulation disorder, N=52; anxiety disorder, N=42; attention deficit hyperactivity disorder, N=40; and healthy volunteers, N=61). Irritability was measured by parent and child reports on the Affective Reactivity Index. The fMRI paradigm was a cued-attention task differentiating neural activity in response to frustration (rigged feedback) from activity during attention orienting in the trial following frustration.

RESULTS

Whole-brain activation analyses revealed associations with irritability during attention orienting following frustration. Irritability was positively associated with frontal-striatal activation, specifically in the dorsolateral prefrontal cortex, inferior frontal gyrus, and caudate. Age moderated the association between irritability and activation in some frontal and posterior regions (the anterior cingulate cortex, medial frontal gyrus, cuneus, precuneus, and superior parietal lobule [F=19.04-28.51, df=1, 189, partial eta squared=0.09-0.13]). Specifically, higher irritability was more strongly related to increased activation in younger youths compared with older youths.

CONCLUSIONS

Following frustration, levels of irritability correlated with activity in neural systems mediating attention orienting, top-down regulation of emotions, and motor execution. Although most associations were independent of age, dysfunction in the anterior cingulate cortex and posterior regions was more pronounced in young children with irritability.

Deficits in emotion recognition are associated with depressive symptoms in youth with disruptive mood dysregulation disorder

BACKGROUND

Although severe irritability is a predictor of future depression according to recent meta-analytic evidence, other mechanisms for this developmental transition remain unclear. In this study, we test whether deficits in emotion recognition may partially explain this specific association in youth with severe irritability, defined as disruptive mood dysregulation disorder (DMDD).

METHODS

Participants aged 8-20 years (M = 13.3, SD = 2.8) included youth with DMDD, split by low depressive (DMDD/LD; n = 52) and high depressive (DMDD/HD; n = 25) symptoms, and healthy controls (HC; n = 39). A standardized computer task assessed emotion recognition of faces and voices of adults and children expressing happiness, fear, sadness, and anger. A Group (3) × Emotion (4) × Actor (2) × Modality (2) repeated measures analysis of covariance examined the number of errors and misidentification of emotions. Linear regression was then used to assess whether deficits in emotion recognition were predictive of depressive symptoms at a 1 year follow-up.

RESULTS

DMDD/HD youth were more likely to interpret happy stimuli as angry and fearful compared to DMDD/LD (happy as angry: p = 0.018; happy as fearful: p = 0.008) and HC (happy as angry: p = 0.014; happy as fearful: p = 0.024). In youth with DMDD, the misidentification of happy stimuli as fearful was associated with higher depressive symptoms at follow-up (β = 0.43, p = 0.017), independent of baseline depressive and irritability symptoms.

CONCLUSIONS

Deficits in emotion recognition are associated, cross-sectionally and longitudinally, with depressive symptoms in youth with severe irritability. Future studies should examine the neural correlates that contribute to these associations.

A Developmental Twin Study of Emotion Recognition and Its Negative Affective Clinical Correlates

OBJECTIVE

Youth with psychiatric disorders distinguished by irritability, including depression and associated trait neuroticism, show deficits in the ability to recognize facial expressions of emotion, particularly happiness. However, the contribution of genetic and environmental factors to this ability remains unknown. The present study examined this trait in twins to assess the genetic and environmental influences on face-emotion recognition abilities and their association with irritability, neuroticism, and depression.

METHOD

Child and adolescent twins (N = 957 from 496 families) 9 to 17 years old rated their irritability (on the Affective Reactivity Index), neuroticism (on the Junior Eysenck Personality Questionnaire), and depression (on the Short Mood and Feelings Questionnaire) and completed a face-emotion labeling task. Faces depicting anger, disgust, fear, happiness, sadness, and surprise were morphed with a neutral face, yielding 10 levels of increasing emotional expressivity. Biometrical twin analyses evaluated contributions of genetic and environmental factors to the etiology of face-emotion recognition and its association with irritability, neuroticism, and depression.

RESULTS

Recognition of each emotion was heritable; common and specific sets of genetic factors influenced all emotions and individual emotions, respectively. Irritability, neuroticism, and depression were modestly and negatively correlated with emotion recognition, particularly the recognition of happiness. For irritability and neuroticism, this correlation appeared largely due to genetic factors.

CONCLUSION

This study maps genetic and environmental contributions to face-emotion recognition and its association with irritability, neuroticism, and depression. Findings implicate common genetic factors in deficits regarding the recognition of happiness associated with irritability and neuroticism in childhood and adolescence.

A double-blind, randomized, placebo-controlled trial of a computer-based Interpretation Bias Training for youth with severe irritability: a study protocol

Background

Severe, chronic, and impairing irritability is a common presenting clinical problem in youth. Indeed, it was recently operationalized as disruptive mood dysregulation disorder (DMDD) in the DSM-5. However, to date, there are no evidence-based treatments that were specifically developed for DMDD. The current randomized controlled trial assesses the efficacy of a computer-based cognitive training intervention (Interpretation Bias Training; IBT) in youth with DMDD. IBT aims to reduce irritability by altering judgments of ambiguous face-emotions through computerized feedback. IBT is based on previous findings that youth with irritability-related psychopathology rate ambiguous faces as more hostile and fear producing.

Methods/design

This is a double-blind, randomized controlled trial of IBT in 40 youth with DMDD. Participants will be randomized to receive four IBT sessions (Active vs. Sham training) over 4 days. Active IBT provides computerized feedback to change ambiguous face-emotion interpretations towards happy interpretations. Face-emotion judgments are performed pre and post training, and for 2 weeks following training. Blinded clinicians will conduct weekly clinical ratings. Primary outcome measures assess changes in irritability using the clinician-rated Affective Reactivity Index (ARI) and Clinical Global Impressions-Improvement (CGI-I) scale for DMDD, as well as parent and child reports of irritability using the ARI. Secondary outcome measures include clinician ratings of depression, anxiety, and overall impairment. In addition, parent and child self-report measures of depression, anxiety, anger, social status, and aggression will be collected.

Discussion

The study described in this protocol will perform the first RCT testing the efficacy of IBT in reducing irritability in youth with DMDD. Developing non-pharmacological treatment options for youth suffering from severe, chronic irritability is important to potentially augment existing treatments.

Trial registration

ClinicalTrials.gov, ID: NCT02531893. Registered on 25 August 2015.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2960-5) contains supplementary material, which is available to authorized users.

Reward Processing in Depression: A Conceptual and Meta-Analytic Review Across fMRI and EEG Studies

OBJECTIVE

A role for aberrant reward processing in the pathogenesis of depression has long been proposed. However, no review has yet examined its role in depression by integrating conceptual and quantitative findings across functional MRI (fMRI) and EEG methodologies. The authors quantified these effects, with an emphasis on development.

METHOD

A total of 38 fMRI and 12 EEG studies were entered into fMRI and EEG meta-analyses. fMRI studies primarily examined reward anticipation and reward feedback. These were analyzed using the activation likelihood estimation method. EEG studies involved mainly the feedback-related negativity (FRN) event-related potential, and these studies were analyzed using random-effects meta-analysis of the association between FRN and depression.

RESULTS

Analysis of fMRI studies revealed significantly reduced striatal activation in depressed compared with healthy individuals during reward feedback. When region-of-interest analyses were included, reduced activation was also observed in reward anticipation, an effect that was stronger in individuals under age 18. FRN was also significantly reduced in depression, with pronounced effects in individuals under age 18. In longitudinal studies, reduced striatal activation in fMRI and blunted FRN in EEG were found to precede the onset of depression in adolescents.

CONCLUSIONS

Taken together, the findings show consistent neural aberrations during reward processing in depression, namely, reduced striatal signal during feedback and blunted FRN. These aberrations may underlie the pathogenesis of depression and have important implications for development of new treatments.

A Population-Based Twin Study of Childhood Irritability and Internalizing Syndromes

Childhood irritability exhibits significant theoretical and empirical associations with depression and anxiety syndromes. The current study used the twin design to parse genetic and environmental contributions to these relationships. Children ages 9-14 from 374 twin pairs were assessed for irritability and symptoms of depression, generalized anxiety, panic, social phobia, and separation anxiety using dimensional self-report instruments. Multivariate structural equation modeling decomposed the correlations between these syndromes into genetic and environmental components to examine shared and specific risk domains. Irritability had significant associations with each internalizing symptom domain. Genetic contributions to irritability are moderately correlated with genetic risk for symptoms of depression, generalized anxiety, and separation anxiety with weaker overlap with the other anxiety syndromes. Familial and specific environmental risk factors explained covariation among syndromes and indicated potential syndrome-specific risk. There is substantial overlap among the genetic and environmental factors that influence individual differences in irritability and those that increase liability for depression and anxiety symptoms in children. These findings deepen the current understanding of childhood internalizing risk factors and provide important implications for syndrome prediction and susceptibility gene discovery efforts.

Practitioner Review: Definition, recognition, and treatment challenges of irritability in young people

BACKGROUND

Irritability is one of the most common reasons for referral to child and adolescent mental health services and is the main characteristic of the new diagnosis of disruptive mood dysregulation disorder (DMDD). However, the recognition and management of irritability presents a major challenge in clinical practice and may be partly responsible for the dramatic increase in antipsychotic prescribing in recent years.

METHODS

In this review, we provide up-to-date information on the definition and mechanisms underlying irritability, and its assessment in clinical practice. We aim to discuss the latest research on DMDD, and the presence of severe irritability in the context of other disorders, as well as to recommend a treatment algorithm.

RESULTS

Severe irritability is associated with aberrant reward processing and bias toward threatening stimuli. Several measures are available to easily assess irritability. The recent diagnosis of DMDD captures children whose main problem is severe irritability and differ from those with bipolar disorder in longitudinal outcomes, family history, and behavioral and neural correlates. Treatment of irritability might depend on the context it appears. Indirect evidence suggests that parent management training (PMT) and cognitive behavioral therapy (CBT) are the most supported psychological treatments for irritability.

CONCLUSIONS

Irritability, recognized as a mood problem rather than a purely behavioral manifestation, is a common condition for young people. Practitioners should not ignore irritability as it is associated with substantial morbidity and impairment. Although there are no trials with irritability as main outcome, clinicians can apply several existing pharmacological and psychological interventions for its treatment. Also, new promising approaches relying on pathophysiological findings, such as exposure-based cognitive behavioral therapy techniques and interpretation bias training (IBT), are being currently investigated.

A Latent Variable Approach to Differentiating Neural Mechanisms of Irritability and Anxiety in Youth

IMPORTANCE

Comorbidity is ubiquitous in psychiatry, but it is unclear how to differentiate neural mechanisms of co-occurring symptoms. Pediatric irritability and anxiety symptoms are prevalent and frequently co-occur. Threat orienting is pertinent to both phenotypes and is an ideal context in which to examine their unique and common neural mechanisms.

OBJECTIVES

To decompose the unique and shared variances of pediatric irritability and anxiety symptoms and to determine neural correlates of these differentiated phenotypes during threat orienting.

DESIGN, SETTING, AND PARTICIPANTS

This investigation was a cross-sectional functional magnetic resonance imaging study. The setting was a research clinic at the National Institute of Mental Health. Participants were youth aged 8 to 18 years spanning multiple diagnostic categories (141 youth with disruptive mood dysregulation disorder, anxiety disorder, and/or attention-deficit/hyperactivity disorder and 56 healthy youth). This combination provided wide variation in levels of irritability and anxiety symptoms. Data were acquired between June 30, 2012, and June 28, 2016.

MAIN OUTCOMES AND MEASURES

Participants and parents rated youth's irritability on the Affective Reactivity Index and anxiety on the Screen for Child Anxiety Related Emotional Disorders. Bifactor analysis decomposed the unique and shared variances. A functional magnetic resonance imaging dot-probe task assessed attention orienting to angry (ie, threat) vs neutral faces. Whole-brain analyses examined associations between the bifactor-derived phenotypes and both neural activity and amygdala functional connectivity.

RESULTS

Among 197 participants included in the final analysis, the mean (SD) age was 13.1 (2.7) years, and 91 (46.2%) were female. The best-fit bifactor model (Comparative Fit Index, 0.959; Root Mean Square Error of Approximation, 0.066) included unique factors of parent-reported irritability, youth-reported irritability, and anxiety, as well as a common factor of negative affectivity. When the task required attention away from threat, higher parent-reported irritability was associated with increased activity in the insula, caudate, dorsolateral and ventrolateral prefrontal cortex, and inferior parietal lobule (t189≥4.15 for all, P < .001 for all). In contrast, higher anxiety was associated with decreased amygdala connectivity to the cingulate, thalamus, and precentral gyrus (t189≤-4.19 for all, P < .001 for all). These distinctive neural correlates did not emerge using a diagnostic approach.

CONCLUSIONS AND RELEVANCE

A latent variable approach to parsing co-occurring symptom dimensions revealed a novel double dissociation. During orientation away from threat, only irritability was associated with neural activity, whereas only anxiety was associated with amygdala connectivity. Despite the challenges of symptom co-occurrence for clinical neuroscience, data-driven phenotyping may facilitate a path forward.

Reliability of neural activation and connectivity during implicit face emotion processing in youth

Face emotion imaging paradigms are widely used in both healthy and psychiatric populations. Here, in children and adolescents, we evaluate the test-retest reliability of blood oxygenation-level dependent (BOLD) activation and task-based functional connectivity on a widely used implicit face emotion processing task (i.e., gender labeling). Twenty-five healthy youth (M age = 13.97 year s; 60% female) completed two functional magnetic resonance imaging (fMRI) scan sessions approximately two months apart. Participants identified the gender of faces displaying angry, fearful, happy, and neutral emotions. A Bayesian adaptation of the intraclass correlation (ICC) assessed reliability of evoked BOLD activation and amygdala seed-based functional connectivity on task events vs. baseline as well as contrasts between face emotions. For each face emotion vs. baseline, good reliability of activation was demonstrated across key emotion processing regions including middle, medial, and inferior frontal gyri. However, contrasts between face emotions yielded variable results. Contrasts of angry to neutral or happy faces exhibited good reliability of amygdala connectivity to prefrontal regions. Contrasts of fearful to happy faces exhibited good reliability of activation in the anterior cingulate. Findings inform the reproducibility literature and emphasize the need for continued evaluation of task reliability.

Psychosocial Treatment of Irritability in Youth

PURPOSE OF REVIEW

Chronic, severe irritability is a common presenting problem in children and adolescents. Disruptive mood dysregulation disorder (DMDD) was added to the DSM-5 in recognition of this public health need. Currently there are no well-established, evidence-based pharmacological or psychosocial treatments specifically for DMDD. Here, we focus on psychosocial interventions. In addition to reviewing published research, we present preliminary, open trial data on a novel exposure-based cognitive-behavioral therapy (CBT) targeting severe irritability, as is present in DMDD.

RECENT FINDINGS

In the published literature, parent management training (PMT) comprises parent-based interventions designed to treat youth disruptive behavior. Child-based interventions for disruptive behavior include CBT focused on social cognition and problem-solving. Based on identified treatment gaps for severe irritability in children and adolescents, novel psychosocial interventions are being developed. We have developed a CBT for severe irritability that integrates exposure techniques, drawn from anxiety treatment, with selected PMT techniques. Data from an open pilot trial (N=10) suggest feasibility.

SUMMARY

Promising psychosocial treatments are being developed for DMDD. Future directions include testing these new therapies against extant interventions. Increased research on the biological and psychological mechanisms mediating irritability will further bridge the treatment gap for youth and families.

Identifying Clinically Significant Irritability in Early Childhood

OBJECTIVE

Advances in developmentally sensitive measurement have enabled differentiation of normative versus clinically salient irritability in early childhood. However, clinical application of these measures is still nascent. The authors developed an optimized model of clinically salient irritable behaviors at preschool age. Based on this model, the authors derived an empirically based cutoff in relation to concurrent DSM-5 irritability-related disorders (i.e., oppositional defiant disorder, disruptive mood dysregulation disorder, other depressive disorders) and used longitudinal models to test the predictive validity of the cutoff for impairment and irritability trajectories and later DSM disorders.

METHOD

Preschool children oversampled for irritability were followed over 3 time points into early school age (N = 425; mean age at baseline 4.7 years, mean follow-up 2.9 years). Mothers reported on children's irritability using the developmentally validated Multidimensional Assessment of Profile of Disruptive Behavior (MAP-DB) Temper Loss scale, impairment using the Family Life Impairment Scale, and DSM categories using the Preschool Age Psychiatric Assessment and the Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version.

RESULTS

Of 22 MAP-DB Temper Loss behaviors, 2 behaviors-1 normative (easily frustrated) and 1 rare dysregulated (destructive tantrums)-were uniquely related to cross-domain impairment. At baseline, these 2 irritability items identified diagnostic status (oppositional defiant disorder, disruptive mood dysregulation disorder, other depressive disorders) with good sensitivity (70-73%) and specificity (74-83%). Children above the irritability cutoff at baseline also exhibited more persistent irritability and impairment and greater likelihood of DSM disorders in early school age.

CONCLUSION

Clinical identification of early-onset irritability can be enhanced using brief, developmentally optimized indicators. Further research to apply these findings to tiered early intervention is important.

Intraclass correlation: Improved modeling approaches and applications for neuroimaging

Intraclass correlation (ICC) is a reliability metric that gauges similarity when, for example, entities are measured under similar, or even the same, well-controlled conditions, which in MRI applications include runs/sessions, twins, parent/child, scanners, sites, and so on. The popular definitions and interpretations of ICC are usually framed statistically under the conventional ANOVA platform. Here, we provide a comprehensive overview of ICC analysis in its prior usage in neuroimaging, and we show that the standard ANOVA framework is often limited, rigid, and inflexible in modeling capabilities. These intrinsic limitations motivate several improvements. Specifically, we start with the conventional ICC model under the ANOVA platform, and extend it along two dimensions: first, fixing the failure in ICC estimation when negative values occur under degenerative circumstance, and second, incorporating precision information of effect estimates into the ICC model. These endeavors lead to four modeling strategies: linear mixed-effects (LME), regularized mixed-effects (RME), multilevel mixed-effects (MME), and regularized multilevel mixed-effects (RMME). Compared to ANOVA, each of these four models directly provides estimates for fixed effects and their statistical significances, in addition to the ICC estimate. These new modeling approaches can also accommodate missing data and fixed effects for confounding variables. More importantly, we show that the MME and RMME approaches offer more accurate characterization and decomposition among the variance components, leading to more robust ICC computation. Based on these theoretical considerations and model performance comparisons with a real experimental dataset, we offer the following general-purpose recommendations. First, ICC estimation through MME or RMME is preferable when precision information (i.e., weights that more accurately allocate the variances in the data) is available for the effect estimate; when precision information is unavailable, ICC estimation through LME or the RME is the preferred option. Second, even though the absolute agreement version, ICC(2,1), is presently more popular in the field, the consistency version, ICC(3,1), is a practical and informative choice for whole-brain ICC analysis that achieves a well-balanced compromise when all potential fixed effects are accounted for. Third, approaches for clear, meaningful, and useful result reporting in ICC analysis are discussed. All models, ICC formulations, and related statistical testing methods have been implemented in an open source program 3dICC, which is publicly available as part of the AFNI suite. Even though our work here focuses on the whole-brain level, the modeling strategy and recommendations can be equivalently applied to other situations such as voxel, region, and network levels.

Test-retest reliability of the facial expression labeling task

Recognizing others' emotional expressions is vital for socioemotional development; impairments in this ability occur in several psychiatric disorders. Further study is needed to map the development of this ability and to evaluate its components as potential transdiagnostic endophenotypes. Before doing so, however, research is required to substantiate the test-retest reliability of scores of the face emotion identification tasks linked to developmental psychopathology. The current study estimated test-retest reliability of scores of one such task, the facial expression labeling task (FELT) among a sample of twin children (N = 157; ages 9-14). Participants completed the FELT at two visits two to five weeks apart. Participants discerned the emotion presented of faces depicting six emotions (i.e., happiness, anger, sadness, fear, surprise, and disgust) morphed with a neutral face to provide 10 levels of increasing emotional expressivity. The present study found strong test-retest reliability (Pearson r) of the FELT scores across all emotions. Results suggested that data from this task may be effectively analyzed using a latent growth curve model to estimate overall ability (i.e., intercept; r's = 0.76-0.85) and improvement as emotions become clearer (i.e., linear slope; r's = 0.69-0.83). Evidence of high test-retest reliability of this task's scores informs future developmental research and the potential identification of transdiagnostic endophenotypes for child psychopathology. (PsycINFO Database Record

Clinical Correlates of Carbon Dioxide Hypersensitivity in Children

OBJECTIVE

Hypersensitivity to carbon dioxide (CO₂)-enriched air may be a promising risk marker for anxiety disorders. Among adult and adolescent samples, heterogeneity in distress response to the CO₂ challenge task indexes 3 underlying classes of individuals, which distinguish between sustained and acute threat response as markers for internalizing disorders, broadly, and anxiety disorders, specifically. The present study examines latent classes in children's response to the CO₂ challenge task to clarify the association of CO₂ hypersensitivity with anxiety and internalizing symptomatology in childhood.

METHOD

Healthy children from a community twin sample (N = 538; age 9-13 years) rated anxious distress every 2 minutes while breathing air enriched to 7.5% CO₂ for 8 minutes. Latent growth mixture modeling evaluated potential classes of individuals with characteristic trajectories of distress during the task to clarify the association with internalizing disorder symptoms and related traits (e.g., anxiety sensitivity, irritability).

RESULTS

Although all participants reported increased distress during the task, interindividual heterogeneity in distress indexed 3 underlying classes: a consistently low class ("low"), a consistently high class ("high"), and participants who demonstrated markedly increased acute distress ("acute"). Compared to the low class, the high class reported greater internalizing psychopathology, whereas membership in the acute class was associated with experiencing a panic-like event during the task.

CONCLUSION

As in older individuals, 3 distinct trajectories emerged to capture interindividual heterogeneity in children's distress during the CO₂ challenge task. These classes were distinguished by clinical validators that reinforce the association of CO₂ hypersensitivity and internalizing disorder phenotypes in children.

Behavioral and Neural Sustained Attention Deficits in Bipolar Disorder and Familial Risk of Bipolar Disorder

BACKGROUND

Few neuroimaging studies compare individuals affected with bipolar disorder (BP), at high familial risk of BP, and at low risk to identify endophenotypes for BP. None have examined variability in attention, despite promising behavioral work in this area. We used functional magnetic resonance imaging (fMRI) methods uniquely powered to compare the neural correlates of attention variability in these three groups.

METHODS

The present study examined 8- to 25-year-old individuals (n = 106) who completed an fMRI attention task: 24 with BP, 29 at risk based on a first-degree relative with BP, and 53 healthy, low-risk individuals. Group differences in intrasubject variability in reaction time were examined, and a sophisticated fMRI analytic approach was used to quantify precisely trialwise associations between reaction time and brain activity. The latter has not been examined previously in BP or risk of BP.

RESULTS

Relative to healthy individuals, those with BP or at risk for BP exhibited increased reaction time variability (F_2,102 = 4.26, p = .02, η_p² = .08). Importantly, we identified blunted relationships between trialwise variation in reaction time and brain activity in the inferior and middle frontal gyri, precuneus, cingulate cortex, caudate, and postcentral gyrus (all regions: p < .001, η_p² > .06) in both at-risk and BP individuals compared with healthy, low-risk individuals. This blunting partially mediated group differences in reaction time variability (β = .010, 95% confidence interval 0.002 to 0.020, Sobel Z = 2.08, p = .038).

CONCLUSIONS

Blunting in key frontal, cingulate, and striatal areas was evident in unaffected, at-risk individuals and in euthymic BP patients. Elucidating such novel neural endophenotypes can facilitate new approaches to BP prediction, diagnosis, and prevention.

Anxiety symptoms and children's eye gaze during fear learning

BACKGROUND

The eye region of the face is particularly relevant for decoding threat-related signals, such as fear. However, it is unclear if gaze patterns to the eyes can be influenced by fear learning. Previous studies examining gaze patterns in adults find an association between anxiety and eye gaze avoidance, although no studies to date examine how associations between anxiety symptoms and eye-viewing patterns manifest in children. The current study examined the effects of learning and trait anxiety on eye gaze using a face-based fear conditioning task developed for use in children.

METHODS

Participants were 82 youth from a general population sample of twins (aged 9-13 years), exhibiting a range of anxiety symptoms. Participants underwent a fear conditioning paradigm where the conditioned stimuli (CS+) were two neutral faces, one of which was randomly selected to be paired with an aversive scream. Eye tracking, physiological, and subjective data were acquired. Children and parents reported their child's anxiety using the Screen for Child Anxiety Related Emotional Disorders.

RESULTS

Conditioning influenced eye gaze patterns in that children looked longer and more frequently to the eye region of the CS+ than CS- face; this effect was present only during fear acquisition, not at baseline or extinction. Furthermore, consistent with past work in adults, anxiety symptoms were associated with eye gaze avoidance. Finally, gaze duration to the eye region mediated the effect of anxious traits on self-reported fear during acquisition.

CONCLUSIONS

Anxiety symptoms in children relate to face-viewing strategies deployed in the context of a fear learning experiment. This relationship may inform attempts to understand the relationship between pediatric anxiety symptoms and learning.

Complementary Features of Attention Bias Modification Therapy and Cognitive-Behavioral Therapy in Pediatric Anxiety Disorders

OBJECTIVE

In the treatment of anxiety disorders, attention bias modification therapy (ABMT) and cognitive-behavioral therapy (CBT) may have complementary effects by targeting different aspects of perturbed threat responses and behaviors. ABMT may target rapid, implicit threat reactions, whereas CBT may target slowly deployed threat responses. The authors used amygdala-based connectivity during a threat-attention task and a randomized controlled trial design to evaluate potential complementary features of these treatments in pediatric anxiety disorders.

METHOD

Prior to treatment, youths (8-17 years old) with anxiety disorders (N=54), as well as healthy comparison youths (N=51), performed a threat-attention task during functional MRI acquisition. Task-related amygdala-based functional connectivity was assessed. Patients with and without imaging data (N=85) were then randomly assigned to receive CBT paired with either active or placebo ABMT. Clinical response was evaluated, and pretreatment amygdala-based connectivity profiles were compared among patients with varying levels of clinical response.

RESULTS

Compared with the CBT plus placebo ABMT group, the CBT plus active ABMT group exhibited less severe anxiety after treatment. The patient and healthy comparison groups differed in amygdala-insula connectivity during the threat-attention task. Patients whose connectivity profiles were most different from those of the healthy comparison group exhibited the poorest response to treatment, particularly those who received CBT plus placebo ABMT.

CONCLUSIONS

The study provides evidence of enhanced clinical effects for patients receiving active ABMT. Moreover, ABMT appears to be most effective for patients with abnormal amygdala-insula connectivity. ABMT may target specific threat processes associated with dysfunctional amygdala-insula connectivity that are not targeted by CBT alone. This may explain the observation of enhanced clinical response to CBT plus active ABMT.

Latent structure of negative valence measures in childhood

BACKGROUND

Internalizing disorders (IDs), consisting of the syndromes of anxiety and depression, are common, debilitating conditions often having onsets in adolescence. Scientists have developed dimensional self-report instruments that assess putative negative valence system (NVS) trait-like constructs as complimentary phenotypes to clinical symptoms. These include various measures that index temperamental predispositions to IDs and correlate with neural substrates of fear, anxiety, and affective regulation. This study sought to elucidate the overarching structure of putative NVS traits and their relationship to early manifestations of ID symptomatology.

METHODS

The sample consisted of 768 juvenile twin subjects ages 9-13. Together with ID symptoms, extant validated instruments were chosen to assess a broad spectrum of NVS traits: anxiety sensitivity, irritability, fearfulness, behavioral activation and inhibition, and neuroticism and extraversion. Exploratory and confirmatory factor analyses (EFA/CFA) were used to investigate the latent structure of the associations among these different constructs and ID symptoms. Bifactor modeling in addition to standard correlated-factor analytic approaches were applied.

RESULTS

Factor analyses produced a primary tripartite solution comprising anxiety/fear, dysphoria, and positive affect among all these measures. Competing DSM-like correlated factors and an RDoC-like NVS bifactor structure provided similar fit to these data.

CONCLUSIONS

Our findings support the conceptual organization of a tripartite latent internalizing domain in developing children. This structure includes both clinical symptoms and a variety of self-report dimensional traits currently in use by investigators. These various constructs are, therefore, most informatively investigated using an inclusive, integrated approach.

Irritability in Youths: A Translational Model

Although irritability is among the most common reasons that children and adolescents are brought for psychiatric care, there are few effective treatments. Developmentally sensitive pathophysiological models are needed to guide treatment development. In this review, the authors present a mechanistic model of irritability that integrates clinical and translational neuroscience research. Two complementary conceptualizations of pathological irritability are proposed: 1) aberrant emotional and behavioral responding to frustrative nonreward, mediated by reward-system dysfunction; and 2) aberrant approach responding to threat, mediated by threat-system dysfunction. The authors review the pathophysiological literature, including animal studies, as well as experimental psychology and clinical studies. Data suggest that, relative to healthy children, irritable children have deficient reward learning and elevated sensitivity to reward receipt and omission. These deficits are associated with dysfunction in the prefrontal cortex, striatum, and amygdala. Youths with irritability also show maladaptive orienting to, interpreting, and labeling of potential threats, associated with prefrontal cortical and amygdalar dysfunction. Abnormalities in reward and threat processing potentiate one another. Future work should test pathophysiological hypotheses and novel interventions targeting reward- and threat-related dysfunction to improve treatment for severe irritability in youths.

Behavioral and Neural Sustained Attention Deficits in Disruptive Mood Dysregulation Disorder and Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

Disruptive mood dysregulation disorder (DMDD), characterized by severe irritability, and attention-deficit/hyperactivity disorder (ADHD) are highly comorbid. This is the first study to characterize neural and behavioral similarities and differences in attentional functioning across these disorders.

METHOD

Twenty-seven healthy volunteers, 31 patients with DMDD, and 25 patients with ADHD (8 to 18 years old) completed a functional magnetic resonance imaging attention task. Group differences in intra-subject variability in reaction time (RT) were examined. The present functional magnetic resonance imaging analytic approach precisely quantified trial-wise associations between RT and brain activity.

RESULTS

Group differences manifested in the relation between RT and brain activity (all regions: p < .01, F > 2.54, partial eta-squared [η_p²] > 0.06). Patients with DMDD showed specific alterations in the right paracentral lobule, superior parietal lobule, fusiform gyrus, and cerebellar culmen. In contrast, patients with DMDD and those with ADHD exhibited blunted compensatory increases in activity on long RT trials. In addition, youth with DMDD exhibited increased activity in the postcentral gyrus, medial frontal gyrus, and cerebellar tonsil and declive (all regions: p < .05, F > 2.46, η_p² > 0.06). Groups in the imaging sample did not differ significantly in intra-subject variability in RT (F_2,79 = 2.664, p = .076, η_p² = 0.063), although intra-subject variability in RT was significantly increased in youth with DMDD and ADHD when including those not meeting strict motion and accuracy criteria for imaging analysis (F_2,96 = 4.283, p = .017, η_p² = 0.083).

CONCLUSION

Patients with DMDD exhibited specific alterations in the relation between pre-stimulus brain activity and RT. Patients with DMDD and those with ADHD exhibited similar blunting of compensatory neural activity in frontal, parietal, and other regions. In addition, patients with DMDD showed increased RT variability compared with healthy youth. This work is the first to identify common and unique behavioral and neural signatures of DMDD and ADHD.

Test-retest reliability and validity of a frustration paradigm and irritability measures

BACKGROUND

Data on the reliability and validity of assessments for irritability, particularly behavioral paradigms, are limited. This study examined the test-retest reliability and validity of a frustration paradigm (the Affective Posner 2 task) and two irritability measures [the Affective Reactivity Index (ARI) and Child Behavior Checklist (CBCL) irritability].

METHODS

Participants were 109 youth from a general population sample of twins (aged 9-14 years). Participants completed two visits that were 2-4 weeks apart. At both visits, participants completed the Affective Posner 2 task and self-reported their irritability using the ARI. Parents reported their child's irritability using the ARI and completed the CBCL.

RESULTS

The Affective Posner 2 task demonstrated good test-retest reliability, with intraclass correlations (ICCs) ranging from .44 to .78. The task effectively evoked negative affect (frustration and unhappiness) at both test and retest, demonstrating its construct validity. Moreover, self-rated frustration and unhappiness during the frustration components of the task correlated positively with self-reported but not parent-reported irritability, providing modest support for convergent validity. Parent- and child-reports of the ARI and parent-reports of the CBCL irritability measure showed excellent test-retest reliability, with ICCs ranging from .88 to .90.

LIMITATIONS

The sample consists of mostly twins aged 9-14 years from the communities. Thus, results may not generalize to non-twin samples or clinical samples outside of this age range.

CONCLUSIONS

The Affective Posner 2 paradigm and the ARI and CBCL irritability scales may be useful tools for longitudinal or treatment research on irritability.

Association of Irritability and Anxiety With the Neural Mechanisms of Implicit Face Emotion Processing in Youths With Psychopathology

IMPORTANCE

Psychiatric comorbidity complicates clinical care and confounds efforts to elucidate the pathophysiology of commonly occurring symptoms in youths. To our knowledge, few studies have simultaneously assessed the effect of 2 continuously distributed traits on brain-behavior relationships in children with psychopathology.

OBJECTIVE

To determine shared and unique effects of 2 major dimensions of child psychopathology, irritability and anxiety, on neural responses to facial emotions during functional magnetic resonance imaging.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional functional magnetic resonance imaging study in a large, well-characterized clinical sample at a research clinic at the National Institute of Mental Health. The referred sample included youths ages 8 to 17 years, 93 youths with anxiety, disruptive mood dysregulation, and/or attention-deficit/hyperactivity disorders and 22 healthy youths.

MAIN OUTCOMES AND MEASURES

The child's irritability and anxiety were rated by both parent and child on the Affective Reactivity Index and Screen for Child Anxiety Related Disorders, respectively. Using functional magnetic resonance imaging, neural response was measured across the brain during gender labeling of varying intensities of angry, happy, or fearful face emotions. In mixed-effects analyses, the shared and unique effects of irritability and anxiety were tested on amygdala functional connectivity and activation to face emotions.

RESULTS

The mean (SD) age of participants was 13.2 (2.6) years; of the 115 included, 64 were male. Irritability and/or anxiety influenced amygdala connectivity to the prefrontal and temporal cortex. Specifically, irritability and anxiety jointly influenced left amygdala to left medial prefrontal cortex connectivity during face emotion viewing (F4,888 = 9.20; P < .001 for mixed model term). During viewing of intensely angry faces, decreased connectivity was associated with high levels of both anxiety and irritability, whereas increased connectivity was associated with high levels of anxiety but low levels of irritability (Wald χ21 = 21.3; P < .001 for contrast). Irritability was associated with differences in neural response to face emotions in several areas (F2, 888 ≥ 13.45; all P < .001). This primarily occurred in the ventral visual areas, with a positive association to angry and happy faces relative to fearful faces.

CONCLUSIONS AND RELEVANCE

These data extend prior work conducted in youths with irritability or anxiety alone and suggest that research may miss important findings if the pathophysiology of irritability and anxiety are studied in isolation. Decreased amygdala-medial prefrontal cortex connectivity may mediate emotion dysregulation when very anxious and irritable youth process threat-related faces. Activation in the ventral visual circuitry suggests a mechanism through which signals of social approach (ie, happy and angry expressions) may capture attention in irritable youth.

Functional connectivity during masked and unmasked face emotion processing in bipolar disorder

Little is known regarding the neural connectivity and correlates during automatic, unconscious face emotion processing in individuals with bipolar disorder (BD). In this study, 14 adults with BD and 14 healthy volunteers (HV) underwent fMRI scanning while completing an affective priming task with unconsciously perceived and consciously perceived faces (angry, happy, neutral, blank oval). We found that, regardless of awareness level and emotion types, BD patients exhibited diminished functional connectivity between amygdala and ventromedial prefrontal cortex (vmPFC) compared to HV. This connectivity finding is present in the absence of activation differences in amygdala. In addition, in medial frontal gyrus, BD patients displayed greater activation while HV displayed less activation to angry and neutral faces compared to blank ovals. These results suggest that aberrant amygdala-vmPFC connectivity and neural dysfunction in areas implicated in appraisal and expression of emotions (medial frontal gyrus) may be the pathophysiological correlates of emotional processing in BD regardless of awareness level.

The Twin Study of Negative Valence Emotional Constructs

The Twin Study of Negative Valence Emotional Constructs is a multi-site study designed to examine the relationship between a broad selection of potential measures designed to assess putative endophenotypes for negative valence systems (NVS) and early symptoms of internalizing disorders (IDs). In this article, we describe the sample characteristics, data collection protocols, and measures used. Pre-adolescent Caucasian twin pairs were recruited through the Mid-Atlantic Twin Registry; data collection began in February of 2013. Enrolled twins completed various dimensional self-report measures along with cognitive, emotional, and psychophysiological tasks designed to assess NVS function. Parents also completed surveys about their twins and themselves. In addition, a subset of the twins also participated in a neuroimaging protocols. Data collection is in the final stages, and preliminary analyses are underway. The findings will potentially expand our understanding of the mechanisms by which genetic and environmental factors contribute to individual differences in NVS phenotypes and provide new insights into underlying risk factors for IDs.

Neurocognitive functioning in euthymic patients with bipolar disorder and unaffected relatives: A review of the literature

BACKGROUND

Neurocognitive deficits are present in bipolar disorder (BD) patients and their unaffected (nonbipolar) relatives, but it is not clear which domains are most often impaired and the extent of the impairment resulting from shared genetic factors. In this literature review, we address these issues and identify specific neurocognitive tasks most sensitive to cognitive deficits in patients and unaffected relatives.

METHOD

We conducted a systematic review in Web of Science, PubMed/Medline and PsycINFO databases.

RESULTS

Fifty-one articles assessing cognitive functioning in BD patients (23 studies) and unaffected relatives (28 studies) were examined. Patients and, less so, relatives show impairments in attention, processing speed, verbal learning/memory, and verbal fluency.

CONCLUSION

Studies were more likely to find impairment in patients than relatives, suggesting that some neurocognitive deficits may be a result of the illness itself and/or its treatment. However, small sample sizes, differences among relatives studied (e.g., relatedness, diagnostic status, age), and differences in assessment instruments may contribute to inconsistencies in reported neurocognitive performance among relatives. Additional studies addressing these issues are needed.

Neural Correlates of Irritability in Disruptive Mood Dysregulation and Bipolar Disorders

OBJECTIVE

Bipolar disorder and disruptive mood dysregulation disorder (DMDD) are clinically and pathophysiologically distinct, yet irritability can be a clinical feature of both illnesses. The authors examine whether the neural mechanisms mediating irritability differ between bipolar disorder and DMDD, using a face emotion labeling paradigm because such labeling is deficient in both patient groups. The authors hypothesized that during face emotion labeling, irritability would be associated with dysfunctional activation in the amygdala and other temporal and prefrontal regions in both disorders, but that the nature of these associations would differ between DMDD and bipolar disorder.

METHOD

During functional MRI acquisition, 71 youths (25 with DMDD, 24 with bipolar disorder, and 22 healthy youths) performed a labeling task with happy, fearful, and angry faces of varying emotional intensity.

RESULTS

Participants with DMDD and bipolar disorder showed similar levels of irritability and did not differ from each other or from healthy youths in face emotion labeling accuracy. Irritability correlated with amygdala activity across all intensities for all emotions in the DMDD group; such correlation was present in the bipolar disorder group only for fearful faces. In the ventral visual stream, associations between neural activity and irritability were found more consistently in the DMDD group than in the bipolar disorder group, especially in response to ambiguous angry faces.

CONCLUSIONS

These results suggest diagnostic specificity in the neural correlates of irritability, a symptom of both DMDD and bipolar disorder. Such evidence of distinct neural correlates suggests the need to evaluate different approaches to treating irritability in the two disorders.

A re-examination of process-outcome relations in cognitive therapy for depression: Disaggregating within-patient and between-patient effects

OBJECTIVE

We previously examined alliance and therapist adherence as predictors of symptom change. Applying a new analytic strategy, we can ensure that any relations identified were not attributable to stable patient characteristics.

METHOD

Participants were 57 depressed cognitive therapy patients. We disaggregated within- and between-patient variation in process measures.

RESULTS

Between-patients, variability in adherence to Cognitive Methods and Negotiating/Structuring predicted patients' symptom change. Within-patients, only variability in ratings of adherence to Cognitive Methods predicted next-session symptom change.

CONCLUSIONS

Relations involving between-patient process variables are potentially attributable to stable patient characteristics. However, the relation of within-patient Cognitive Methods and session-to-session symptom change cannot be attributed to stable characteristics and is consistent with a causal relationship.