The RDoC framework: facilitating transition from ICD/DSM to dimensional approaches that integrate neuroscience and psychopathology

Symptom dimensions to address heterogeneity in tinnitus

Tinnitus, the auditory phantom percept, is a well-known heterogenous disorder with multiple subtypes. Researchers and clinicians have tried to classify these subtypes according to clinical profiles, aetiologies, and response to treatment with little success. The occurrence of overlapping tinnitus subtypes suggests that the disorder exists along a continuum of severity, with no clear distinct boundaries. In this perspective, we propose a neuro-mechanical framework, viewing tinnitus as a dimensional disorder which is a complex interplay of its behavioural, biological and neurophysiological phenotypes. Moreover, we explore the potential of these dimensions as interacting networks without a common existing cause, giving rise to tinnitus. Considering tinnitus as partially overlapping, dynamically changing, interacting networks, each representing a different aspect of the unified tinnitus percept, suggests that the interaction of these networks determines the phenomenology of the tinnitus, ultimately leading to a dimensional spectrum, rather than a categorical subtyping. A combination of a robust theoretical framework and strong empirical evidence can advance our understanding of the functional mechanisms underlying tinnitus and ultimately, improve treatment strategies.

Ventral Striatal-Hippocampus Coupling During Reward Processing as a Stratification Biomarker for Psychotic Disorders

BACKGROUND

Altered ventral striatal (vST) activation to reward expectancy is a well-established intermediate phenotype for psychiatric disorders, specifically schizophrenia (SZ). Preclinical research suggests that striatal alterations are related to a reduced inhibition by the hippocampal formation, but its role in human transdiagnostic reward-network dysfunctions is not well understood.

METHODS

We performed functional magnetic resonance imaging during reward processing in 728 individuals including healthy control subjects (n = 396), patients (SZ: n = 46; bipolar disorder: n = 45; major depressive disorder: n = 60), and unaffected first-degree relatives (SZ: n = 46; bipolar disorder: n = 50; major depressive disorder: n = 85). We assessed disorder-specific differences in functional vST-hippocampus coupling and transdiagnostic associations with dimensional measures of positive, negative, and cognitive symptoms. We also probed the genetic underpinning using polygenic risk scores for SZ in a subset of healthy participants (n = 295).

RESULTS

Functional vST-hippocampus coupling was 1) reduced in patients with SZ and bipolar disorder (p_FWE < .05, small-volume corrected [SVC]); 2) associated transdiagnostically to dimensional measures of positive (p_FWE = .01, SVC) and cognitive (p_FWE = .02, SVC), but not negative, (p_FWE > .05, SVC) symptoms; and 3) reduced in first-degree relatives of patients with SZ (p_FWE = .017, SVC) and linked to the genetic risk for SZ in healthy participants (p = .035).

CONCLUSIONS

We provide evidence that reduced vST-hippocampus coupling during reward processing is an endophenotype for SZ linked to positive and cognitive symptoms, supporting current preclinical models of the emergence of psychosis. Moreover, our data indicate that vST-hippocampus coupling is familial and linked to polygenic scores for SZ, supporting the use of this measure as an intermediate phenotype for psychotic disorders.

Classifying major mental disorders genetically

Typically, mental disorders are defined and classified based on clinical symptoms and syndromes. Although clinically useful, current diagnostic systems for psychiatry cause concerns due to the lack of biological mechanisms. Deciphering the relationships among psychiatric traits according to their genetic basis may facilitate understanding the biological mechanisms of psychiatric disorders. Ten mental disorders were classified by genomic structural equation modeling (SEM), which leverages summary results of genome-wide association studies. Attention-deficit/hyperactivity disorder (ADHD), anorexia nervosa (AN), anxiety disorder (ANX), autism spectrum disorder (ASD), bipolar disorder (BD), major depressive disorder (MDD), obsessive-compulsive disorder (OCD), posttraumatic stress disorder (PTSD), schizophrenia (SZ), and Tourette syndrome (TS) were included. The analysis indicates that they are genetically inter-correlated with one another and can be separated based on their general psychopathology. Most disorders have a close partner, forming pairs of traits; only TS is a relatively distinctive condition. At a higher level, MDD, ANX, ADHD, ASD, and PTSD cluster together, while OCD, AN, and TS cluster together. Together, the ten traits constitute a hierarchical classificatory system. This study allows inference of genetically determined classification of the ten mental disorders, which may biologically inform the current diagnostic framework and treatment regimens for mental disorders.

Anhedonia and Suicide

Suicide is a leading cause of death, and presently, there is no definitive clinical indicator of future suicide behaviors. Anhedonia, a transdiagnostic symptom reflecting diminished ability to experience pleasure, has recently emerged as a risk factor for suicidal thoughts and behaviors (STBs). This overview, therefore, has the following aims. First, prior research relating anhedonia to STBs will be reviewed, with a particular focus on clarifying whether anhedonia is more closely associated with suicidal thoughts versus behaviors. Second, the National Institute of Mental Health's Research Domain Criteria Positive Valence Systems provide a useful heuristic to probe anhedonia across different units of analysis, including clinical symptoms, behaviors, neural mechanisms, and molecular targets. Accordingly, anhedonia-related constructs linked to STBs will be detailed as well as promising next steps for future research. Third, although anhedonia is not directly addressed in leading suicide theories, this review will provide potential inroads to explore anhedonia within diathesis-stress and interpersonal suicide frameworks. Last, novel approaches to treat anhedonia as a means of reducing STBs will be examined.

The role of prefrontal cortex in cognitive control and executive function

Concepts of cognitive control (CC) and executive function (EF) are defined in terms of their relationships with goal-directed behavior versus habits and controlled versus automatic processing, and related to the functions of the prefrontal cortex (PFC) and related regions and networks. A psychometric approach shows unity and diversity in CC constructs, with 3 components in the most commonly studied constructs: general or common CC and components specific to mental set shifting and working memory updating. These constructs are considered against the cellular and systems neurobiology of PFC and what is known of its functional neuroanatomical or network organization based on lesioning, neurochemical, and neuroimaging approaches across species. CC is also considered in the context of motivation, as "cool" and "hot" forms. Its Common CC component is shown to be distinct from general intelligence (g) and closely related to response inhibition. Impairments in CC are considered as possible causes of psychiatric symptoms and consequences of disorders. The relationships of CC with the general factor of psychopathology (p) and dimensional constructs such as impulsivity in large scale developmental and adult populations are considered, as well as implications for genetic studies and RDoC approaches to psychiatric classification.

Association between cortical thickness and anxiety measures: A scoping review

Cortical thickness has been increasingly studied in the context of structural-brain-behavior associations, such as anxiety; however, the literature is scattered across methods and research fields. This scoping review aims to summarize the available data concerning the association between cortical thickness and anxiety-related measures and identify the current research gaps. Searches were conducted in PubMed, PsycINFO/PsycARTICLES, Web of Science, OpenGrey and Networked Digital Library of Theses and Dissertations, and reference lists of key studies. Two researchers independently screened the abstracts and full-text reports according to the eligibility criteria, as well as extracted and charted the data. Quantitative and descriptive syntheses were conducted. The included publications (n = 18) reported cross-sectional studies, and 17 used surface-based approaches to estimate cortical thickness. Differences in regional cortical thickness were found to be associated with different anxiety-related measures/processes. Brain regions of interest include the medial orbitofrontal cortex, the ventromedial prefrontal cortex, the insula, the temporo-parietal areas, and the anterior cingulate cortex. However, caution should be warranted when interpreting the available results, as there is high variability in the field across anxiety-related measures, distinctive anxiety disorders, and data processing conditions and analysis. More research into this association is needed, to replicate and clarify existing findings.

Case report: From anxiety disorders to psychosis, a continuum in transitional age youth?

INTRODUCTION

To date, among individuals meeting ultra-high risk criteria for psychosis, the relationship between the presence of anxiety disorders and the risk of psychotic transition raises several unanswered questions.

CASE DESCRIPTION

This case report describes the clinical progression of a 17-year-old male initially presenting anxious symptoms meeting the DSM-V criteria for panic disorder. The patient also reported social withdraw, mild depressive symptoms, insomnia and fatigue. Over a 6 month period, a gradual onset of subthreshold psychotic symptoms suggested a prodromal phase of a psychotic disorder.

DIAGNOSTIC ASSESSMENT AND THERAPEUTIC INTERVENTION

A detailed assessment of UHR criteria for psychosis was performed. The overall level of social and occupational functioning was assessed by the SOFAS, which showed a 35% drop over a 12 months period. The CAARMS, has also been administered. The patient met the diagnostic criteria for UHR, APS group. The care plan included psychiatric follow-up, pharmacologic treatment, individual psychological follow-up and individual and familial psychoeducation. Over a 6 months period, the patient did not experienced a first psychotic episode and presented a partial improvement of psychotic symptoms.

CONCLUSION

The DSM-V categorical approach does not seem to adapt well to early clinical presentations in transitional age youth. A transdiagnostic and dimensional approach allows to better identify at-risk patients of psychiatric disorders and implement early intervention strategies.

Neurocircuitry basis of the opioid use disorder-post-traumatic stress disorder comorbid state: conceptual analyses using a dimensional framework

Understanding the interface between opioid use disorder (OUD) and post-traumatic stress disorder (PTSD) is challenging. By use of a dimensional framework, such as research domain criteria, convergent and targetable neurobiological processes in OUD-PTSD comorbidity can be identified. We hypothesise that, in OUD-PTSD, circuitry that is implicated in two research domain criteria systems (ie, negative valence and cognitive control) underpins dysregulation of incentive salience, negative emotionality, and executive function. We also propose that the OUD-PTSD state might be systematically investigated with approaches outlined within a neuroclinical assessment framework for addictions and PTSD. Our dimensional analysis of the OUD-PTSD state shows how first-line therapeutic approaches (ie, partial μ-type opioid receptor [MOR1] agonism) modulate overlapping neurobiological and clinical features and also provides mechanistic rationale for evaluating polytherapeutic strategies (ie, partial MOR1 agonism, κ-type opioid receptor [KOR1] antagonism, and α-2A adrenergic receptor [ADRA2A] agonism). A combination of these therapeutic mechanisms is projected to facilitate recovery in patients with OUD-PTSD by mitigating negative valence states and enhancing executive control.

A Baldwin interpretation of adult hippocampal neurogenesis: from functional relevance to physiopathology

Hippocampal adult neurogenesis has been associated to many cognitive, emotional, and behavioral functions and dysfunctions, and its status as a selected effect or an "appendix of the brain" has been debated. In this review, we propose to understand hippocampal neurogenesis as the process underlying the "Baldwin effect", a particular situation in evolution where fitness does not rely on the natural selection of genetic traits, but on "ontogenetic adaptation" to a changing environment. This supports the view that a strong distinction between developmental and adult hippocampal neurogenesis is made. We propose that their functions are the constitution and the lifelong adaptation, respectively, of a basic repertoire of cognitive and emotional behaviors. This lifelong adaptation occurs through new forms of binding, i.e., association or dissociation of more basic elements. This distinction further suggests that a difference is made between developmental vulnerability (or resilience), stemming from dysfunctional (or highly functional) developmental hippocampal neurogenesis, and adult vulnerability (or resilience), stemming from dysfunctional (or highly functional) adult hippocampal neurogenesis. According to this hypothesis, developmental and adult vulnerability are distinct risk factors for various mental disorders in adults. This framework suggests new avenues for research on hippocampal neurogenesis and its implication in mental disorders.

Psychosocial functioning in the balance between autism and psychosis: evidence from three populations

Functional impairment is a core feature of both autism and schizophrenia spectrum disorders. While diagnostically independent, they can co-occur in the same individual at both the trait and diagnostic levels. The effect of such co-occurrence is hypothesized to worsen functional impairment. The diametric model, however, suggests that the disorders are etiologically and phenotypically diametrical, representing the extreme of a unidimensional continuum of cognition and behavior. A central prediction of this model is that functional impairment would be attenuated in individuals with mixed symptom expressions or genetic liability to both disorders. We tested this hypothesis in two clinical populations and one healthy population. In individuals with chronic schizophrenia and in individuals with first episode psychosis we evaluated the combined effect of autistic traits and positive psychotic symptoms on psychosocial functioning. In healthy carriers of alleles of copy number variants (CNVs) that confer risk for both autism and schizophrenia, we also evaluated whether variation in psychosocial functioning depended on the combined risk conferred by each CNV. Relative to individuals with biased symptom/CNV risk profiles, results show that functional impairments are attenuated in individuals with relatively equal levels of positive symptoms and autistic traits-and specifically stereotypic behaviors-, and in carriers of CNVs with relatively equal risks for either disorder. However, the pattern of effects along the "balance axis" varied across the groups, with this attenuation being generally less pronounced in individuals with high-high symptom/risk profile in the schizophrenia and CNV groups, and relatively similar for low-low and high-high individuals in the first episode psychosis group. Lower levels of functional impairments in individuals with "balanced" symptom profile or genetic risks would suggest compensation across mechanisms associated with autism and schizophrenia. CNVs that confer equal risks for both disorders may provide an entry point for investigations into such compensatory mechanisms. The co-assessment of autism and schizophrenia may contribute to personalized prognosis and stratification strategies.

A Preliminary Study of Abnormal Centrality of Cortical Regions and Subsystems in Whole Brain Functional Connectivity of Autism Spectrum Disorder Boys

The abnormal cortices of autism spectrum disorder (ASD) brains are uncertain. However, the pathological alterations of ASD brains are distributed throughout interconnected cortical systems. Functional connections (FCs) methodology identifies cooperation and separation characteristics of information process in macroscopic cortical activity patterns under the context of network neuroscience. Embracing the graph theory concepts, this paper introduces eigenvector centrality index (EC score) ground on the FCs, and further develops a new framework for researching the dysfunctional cortex of ASD in holism significance. The important process is to uncover noticeable regions and subsystems endowed with antagonistic stance in EC-scores of 26 ASD boys and 28 matched healthy controls (HCs). For whole brain regional EC scores of ASD boys, orbitofrontal superior medial cortex, insula R, posterior cingulate gyrus L, and cerebellum 9 L are endowed with different EC scores significantly. In the brain subsystems level, EC scores of DMN, prefrontal lobe, and cerebellum are aberrant in the ASD boys. Generally, the EC scores display widespread distribution of diseased regions in ASD brains. Meanwhile, the discovered regions and subsystems, such as MPFC, AMYG, INS, prefrontal lobe, and DMN, are engaged in social processing. Meanwhile, the CBCL externalizing problem scores are associated with EC scores.

The Latent Structure of Negative Symptoms in the General Population in Adolescence and Emerging Adulthood

Negative symptoms predict adverse outcomes within psychotic disorders, in individuals at high-risk for psychosis, and in young people in the community. There is considerable interest in the dimensional structure of negative symptoms in clinical samples, and accumulating evidence suggests a 5-factor structure. Little is known about the underlying structure of negative symptoms in young people despite the importance of this developmental stage for mental health. We used confirmatory factor analysis to test the structure of parent-reported negative symptoms at mean ages 16.32 (SD 0.68, N = 4974), 17.06 (SD 0.88, N = 1469) and 22.30 (SD 0.93, N = 5179) in a community sample. Given previously reported associations between total negative symptoms and genome-wide polygenic scores (GPS) for major depressive disorder (MDD) and schizophrenia in adolescence, we assessed associations between individual subdomains and these GPSs. A 5-factor model of flat affect, alogia, avolition, anhedonia, and asociality provided the best fit at each age and was invariant over time. The results of our linear regression analyses showed associations between MDD GPS with avolition, flat affect, anhedonia, and asociality, and between schizophrenia GPS with avolition and flat affect. We showed that a 5-factor structure of negative symptoms is present from ages 16 to 22 in the community. Avolition was most consistently associated with polygenic liability to MDD and schizophrenia, and alogia was least associated. These findings highlight the value of dissecting negative symptoms into psychometrically derived subdomains and may offer insights into early manifestation of genetic risk for MDD and schizophrenia.

Validity, reliability and clinical utility of mental disorders: The case of ICD-11 schizophrenia

Diagnostic classification systems categorise mental psychopathology in mental disorders. Although these entities are clinical constructs developed by consensus, it has been pointed out that in practice they are usually managed as natural entities and without evaluating aspects related to their nosological construction. The objectives of the study are to review a) the conceptualisation of mental disorders, b) the indicators of validity, reliability and clinical utility, and c) the values ​​of these indicators in ICD-11 schizophrenia. The results show that mental disorders are conceptualised as discrete entities, like the diseases of other areas of medicine; however, differences are observed between these diagnostic categories in clinical practice. The reliability and clinical utility of mental disorders are adequate; however, the validity is not yet clarified. Similarly, ICD-11 schizophrenia demonstrates adequate reliability and clinical utility, but its validity remains uncertain. The conceptualisation of psychopathology in discrete entities may be inadequate for its study, therefore dimensional and mixed models have been proposed. The indicators of validity, reliability and clinical utility enable us to obtain an accurate view of the nosological state of mental disorders when evaluating different aspects of their nosological construction.

Developmental Consequences of Early Life Stress on Risk for Psychopathology: Longitudinal Associations with Children's Multisystem Physiological Regulation and Executive Functioning

The etiology of psychopathology is multifaceted and warrants consideration of factors at multiple levels and across developmental time. Although experiences of adversity in early life have been associated with increased risk of developing psychopathology, pathways toward maladaptation or resilience are complex and depend upon a variety of factors, including individuals' physiological regulation and cognitive functioning. Therefore, in a longitudinal cohort of 113 mother-child dyads, we explored associations from early adverse experiences to physiological co-regulation across multiple systems and subsequent variations in executive functioning. Latent profile analysis derived multisystem profiles based on children's heart rate, respiratory sinus arrhythmia, pre-ejection period, and cortisol measured during periods of rest and reactivity throughout a developmentally challenging protocol. Three distinct profiles of multisystem regulation emerged: heightened multisystem baseline activity (Anticipatory Arousal/ANS Responder), typically adaptive patterns across all systems (Active Copers/Mobilizers) and heightened HPA axis activity (HPA Axis Responders). Path models revealed that children exposed to adversity before 18-months were more likely to evidence an Anticipatory Arousal/ANS Responders response at 36-months, and children in this profile had lower executive functioning scores than the Active Copers/Mobilizers. In sum, these findings provide important information about potential physiological associations linking early adversity to variations in children's task-based executive functioning.

Prolonged NoGo P3 latency as a possible neurobehavioral correlate of aggressive and antisocial behaviors: A Go/NoGo ERP study

Aggressive and antisocial behaviors are detrimental to society and constitute major challenges in forensic mental health settings, yet the associated neural circuitry remains poorly understood. Here, we investigated differences in aggressive and antisocial behaviors between healthy controls (n = 20) and violent mentally disordered offenders (MDOs; n = 26), and examined associations between aggressive and antisocial behaviors, behavioral inhibitory control, and neurophysiological activity across the whole sample (n = 46). Event-related potentials were obtained using EEG while participants completed a Go/NoGo response inhibition task, and aggressive and antisocial behaviors were assessed with the Life History of Aggression (LHA) instrument. Using a robust Bayesian linear regression approach, we found that MDOs scored substantially higher than healthy controls on LHA Aggression and Antisocial subscales. Using the whole sample and after adjusting for age, we found that scores on the LHA Aggression and Antisocial subscales were robustly associated with longer NoGo P3 latency, and less robustly with longer NoGo N2 latency. Post-hoc analyzes suggested that healthy controls and MDOs exhibited similar associations. With several limitations in mind, we suggest that prolonged NoGo P3 latency, reflecting decreased neural efficiency during the later stages of conflict monitoring or outcome evaluation, is a potential neurobehavioral correlate of aggressive and antisocial behaviors.

Early and late signals of unexpected reward contribute to low extraversion and high disinhibition, respectively

Like socio-economic status and cognitive abilities, personality traits predict important life outcomes. Traits that reflect unusually low or high approach motivations, such as low extraversion and high disinhibition, are linked to various forms of mental disorder. Similarly, the dopamine system is theoretically linked to approach motivation traits and to various forms of mental disorder. Identifying neural contributions to extremes of such traits should map to neural sources of psychopathology, with dopamine a prime candidate. Notably, dopamine cells fire in response to unexpected reward, which suggests that the size of non-invasive, scalp-recorded potentials evoked by unexpected reward could reflect sensitivity in approach motivation traits. Here, we evaluated the validity of evoked electroencephalography (EEG) responses to unexpected reward in a monetary gain/loss task to assess approach motivation traits in 137 participants, oversampled for externalizing psychopathology symptoms. We demonstrated that over the 0–400 ms period in which feedback on the outcome was presented, responses evoked by unexpected reward contributed to all theoretically relevant approach motivation trait domains (disinhibition, extraversion and the behavioural activation system); and did so only at times when dopamine responses normally peak and reportedly code salience (70–100 ms) and valuation (200–300 ms). In particular, we linked “dopaminergic” salience and valuation to the psychopathology-related constructs of low extraversion (social anxiety) and high disinhibition (impulsivity) respectively, making the evoked potential components biomarker candidates for indexing aberrant processing of unexpected reward.

A brief video-coaching intervention buffers young children's vulnerability to the impact of caregivers’ depressive symptoms: Examination of differential susceptibility

Informed by the National Institute of Mental Health's Research Domain Criteria (RDoC) and developmental psychopathology frameworks, the current study used cortisol area under the curve with respect to ground (AUCg) as an index of differential sensitivity to context, which was expected to predispose young children with elevated vulnerability to adverse caregiving experiences and adaptive sensitivity to intervention effects. Particularly, the study aimed to determine whether improving caregivers’ responsive parenting through the Filming Interactions to Nurture Development (FIND) intervention would buffer children's biologically embedded vulnerability to caregivers’ depressive symptoms. Data were derived from a randomized controlled trial using pretest–posttest design with low-income families of children aged 4 to 36 months (N = 91). Young children's differential sensitivity was measured using cortisol AUCg during a structured stress paradigm. As hypothesized, children whose cortisol AUCg indicated greater sensitivity to social context exhibited more internalizing and externalizing behaviors in relation to caregivers’ elevated depressive symptoms. Critically, the intervention program was effective in attenuating psychopathology symptoms among the more biologically sensitive children. As proven by rigorous statistical tests, the findings of this study partially supported the differential susceptibility hypotheses, indicating both greater vulnerability to adverse conditions and responsiveness to intervention among children with high levels of cortisol AUCg.

Sleep problems predict next-day suicidal thinking among adolescents: A multimodal real-time monitoring study following discharge from acute psychiatric care

Suicidal thoughts and behaviors (STBs) are major public health concerns among adolescents, and research is needed to identify how risk is conferred over the short term (hours and days). Sleep problems may be associated with elevated risk for STBs, but less is known about this link in youth over short time periods. The current study utilized a multimodal real-time monitoring approach to examine the association between sleep problems (via daily sleep diary and actigraphy) and next-day suicidal thinking in 48 adolescents with a history of STBs during the month following discharge from acute psychiatric care. Results indicated that specific indices of sleep problems assessed via sleep diary (i.e., greater sleep onset latency, nightmares, ruminative thoughts before sleep) predicted next-day suicidal thinking. These effects were significant even when daily sadness and baseline depression were included in the models. Moreover, several associations between daily-level sleep problems and next-day suicidal thinking were moderated by person-level measures of the construct. In contrast, sleep indices assessed objectively (via actigraphy) were either not related to suicidal thinking or were related in the opposite direction from hypothesized. Together, these findings provide some support for sleep problems as a short-term risk factor for suicidal thinking in high-risk adolescents.

Advancing the RDoC initiative through the assessment of caregiver social processes

The relationships infants and young children have with their caregivers are fundamental to their survival and well-being. Theorists and researchers across disciplines have attempted to describe and assess the variation in these relationships, leading to a general acceptance that caregiving is critical to understanding child functioning, including developmental psychopathology. At the same time, we lack consensus on how to assess these fundamental relationships. In the present paper, we first review research documenting the importance of the caregiver-child relationship in understanding environmental risk for psychopathology. Second, we propose that the National Institute of Mental Health's Research Domain Criteria (RDoC) initiative provides a useful framework for extending the study of children's risk for psychopathology by assessing their caregivers' social processes. Third, we describe the units of analysis for caregiver social processes, documenting how the specific subconstructs in the domain of social processes are relevant to the goal of enhancing knowledge of developmental psychopathology. Lastly, we highlight how past research can inform new directions in the study of caregiving and the parent-child relationship through this innovative extension of the RDoC initiative.

The Transdiagnostic Origins of Anxiety and Depression During the Pediatric Period: Linking NIMH Research Domain Criteria (RDoC) Constructs to Ecological Systems

In the last decade, an abundance of research has utilized the NIMH Research Domain Criteria (RDoC) framework to examine mechanisms underlying anxiety and depression in youth. However, relatively little work has examined how these mechanistic intrapersonal processes intersect with context during childhood and adolescence. The current paper covers reviews and meta-analyses that have linked RDoC-relevant constructs to ecological systems in internalizing problems in youth. Specifically, cognitive, biological, and affective factors within the RDoC framework were examined. Based on these reviews and some of the original empirical research they cover, we highlight the integral role of ecological factors to the RDoC framework in predicting onset and maintenance of internalizing problems in youth. Specific recommendations are provided for researchers using the RDoC framework to inform future research integrating ecological systems and development. We advocate for future research and research funding to focus on better integration of the environment and development into the RDoC framework.

Applying new RDoC dimensions to the development of emotion regulation: Examining the influence of maternal emotion regulation on within-individual change in child emotion regulation

While the Research Domain Criteria (RDoC) acknowledges that environmental and developmental influences represent important elements of the RDoC framework, there is little specificity regarding how and when to systematically examine the impact of these dimensions on domains of function. The primary aims of this paper are to demonstrate the ways in which the RDoC can be expanded to include an explicit emphasis on 1) examining within-individual change in developmental processes over time and 2) evaluating the extent to which selective and measurable environmental influences drive meaningful change during key developmental periods. We provide data from an ongoing randomized control trial as a proof of concept to highlight how repeated assessments within an experimental intervention design affords the unique opportunity to test the impact of environmental influences on within-individual change. Using preliminary data from 77 mother-child dyads repeatedly assessed across 12 months during the preschool period, we demonstrate the influence of changes in maternal emotion regulation (ER) on within-individual growth in child ER and link that growth to fewer teacher-reported externalizing problems. In line with this Special Issue, findings are discussed within the context of expanding and clarifying the existing RDoC framework to explicitly incorporate environmental and developmental dimensions.

Which symptoms of depression and anxiety are most strongly associated with happiness? A network analysis of Indian and Kenyan adolescents

BACKGROUND

Network analyses have been applied to understand the relationships between individual symptoms of depression and anxiety. However, little is known about which symptoms are most strongly associated with "positive" indicators of mental health, such as happiness. Furthermore, few studies have examined symptom networks in participants from low- and middle-income countries.

METHODS

To address these gaps, we applied network analyses in a sample of Indian adolescents (Study 1; n=1080) and replicated these analyses in a pre-registered study with Kenyan adolescents (Study 2; n=2176). Participants from both samples completed the same measures of depressive symptoms, anxiety symptoms, and happiness.

RESULTS

Feeling sad and feeling like a failure had the strongest (negative) associations with happiness items. These two symptoms, as well as worrying and feeling nervous, had the strongest associations with other symptoms of depression and anxiety. Symptoms of depression and anxiety formed a single cluster, which was distinct from a cluster of happiness items. Main findings were consistent across the two samples, suggesting a cross-culturally robust pattern.

LIMITATIONS

We used cross-sectional data, and we administered scales assessing a limited subset of symptoms and happiness items.

CONCLUSIONS

Our findings support the idea that some symptoms of depression and anxiety are more strongly associated with happiness. These findings contribute to a body of literature emphasizing the advantages of symptom-level analyses. We discuss how efforts to understand associations between individual symptoms and "positive" mental health indicators, like happiness, could have theoretical and practical implications for clinical psychological science.

Sleep Power Spectral Density and Spindles in PTSD and Their Relationship to Symptom Severity

Sleep disturbances are common in post-traumatic stress disorder (PTSD), although which sleep microarchitectural characteristics reliably classify those with and without PTSD remains equivocal. Here, we investigated sleep microarchitectural differences (i.e., spectral power, spindle activity) in trauma-exposed individuals that met (n = 45) or did not meet (n = 52) criteria for PTSD and how these differences relate to post-traumatic and related psychopathological symptoms. Using ecologically-relevant home sleep polysomnography recordings, we show that individuals with PTSD exhibit decreased beta spectral power during NREM sleep and increased fast sleep spindle peak frequencies. Contrary to prior reports, spectral power in the beta frequency range (20.31-29.88 Hz) was associated with reduced PTSD symptoms, reduced depression, anxiety and stress and greater subjective ability to regulate emotions. Increased fast frequency spindle activity was not associated with individual differences in psychopathology. Our findings may suggest an adaptive role for beta power during sleep in individuals exposed to a trauma, potentially conferring resilience. Further, we add to a growing body of evidence that spindle activity may be an important biomarker for studying PTSD pathophysiology.

A qualitative systematic review of neurocognition in suicide ideators and attempters: Implications for cognitive-based psychotherapeutic interventions

BACKGROUND

Growing evidence suggests cognitive deficits may represent neurocognitive markers with predictive utility in identifying those at risk for suicide. Characterizing these deficits may offer the opportunity to develop targeted interventions.

AIM

The aim of this systematic qualitative review is to provide a synthesis of the published data on neurocognition in suicide ideators and attempters in order to clarify which neurocognitive targets may be most relevant to address using cognitive-based psychotherapeutic strategies in patients at risk for suicide.

RESULTS

A total of 63 studies met criteria for inclusion. The most consistent findings were in depressed suicide attempters, where deficits in executive subdomains of inhibition, selective attention and decision-making, as well as in working memory, were identified. In contrast, no clear pattern of neurocognitive deficits emerged from studies in suicide ideators across diagnoses.

CONCLUSIONS

More studies are needed to clarify the role of cognitive deficits in specific subtypes of individuals at risk for suicide. The findings are discussed in the context of promising research on cognitive remediation and other psychological interventions.

Artificial intelligence applications in social media for depression screening: A systematic review protocol for content validity processes

BACKGROUND

The popularization of social media has led to the coalescing of user groups around mental health conditions; in particular, depression. Social media offers a rich environment for contextualizing and predicting users' self-reported burden of depression. Modern artificial intelligence (AI) methods are commonly employed in analyzing user-generated sentiment on social media. In the forthcoming systematic review, we will examine the content validity of these computer-based health surveillance models with respect to standard diagnostic frameworks. Drawing from a clinical perspective, we will attempt to establish a normative judgment about the strengths of these modern AI applications in the detection of depression.

METHODS

We will perform a systematic review of English and German language publications from 2010 to 2020 in PubMed, APA PsychInfo, Science Direct, EMBASE Psych, Google Scholar, and Web of Science. The inclusion criteria span cohort, case-control, cross-sectional studies, randomized controlled studies, in addition to reports on conference proceedings. The systematic review will exclude some gray source materials, specifically editorials, newspaper articles, and blog posts. Our primary outcome is self-reported depression, as expressed on social media. Secondary outcomes will be the types of AI methods used for social media depression screen, and the clinical validation procedures accompanying these methods. In a second step, we will utilize the evidence-strengthening Population, Intervention, Comparison, Outcomes, Study type (PICOS) tool to refine our inclusion and exclusion criteria. Following the independent assessment of the evidence sources by two authors for the risk of bias, the data extraction process will culminate in a thematic synthesis of reviewed studies.

DISCUSSION

We present the protocol for a systematic review which will consider all existing literature from peer reviewed publication sources relevant to the primary and secondary outcomes. The completed review will discuss depression as a self-reported health outcome in social media material. We will examine the computational methods, including AI and machine learning techniques which are commonly used for online depression surveillance. Furthermore, we will focus on standard clinical assessments, as indicating content validity, in the design of the algorithms. The methodological quality of the clinical construct of the algorithms will be evaluated with the COnsensus-based Standards for the selection of health status Measurement Instruments (COSMIN) framework. We conclude the study with a normative judgment about the current application of AI to screen for depression on social media.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews PROSPERO (registration number CRD42020187874).

Defensive Mobilization During Anticipation of Symptom Provocation: Association With Panic Pathology

BACKGROUND

Anxious apprehension about feared body symptoms is thought to play a crucial role in the development, chronicity, and treatment of panic disorder (PD). In this study, we therefore aimed to elucidate the role of defensive reactivity to anticipated unpleasant symptoms in PD that can contribute to a better understanding of pathomechanisms of PD as well as identification of potential targets in PD-focused interventions. By measuring amygdala-dependent potentiation of the startle reflex, we aimed to investigate whether 1) patients with PD exhibit a specifically increased defensive reactivity to anticipated unpleasant body symptoms and 2) whether clinical severity of panic symptomatology varies with magnitude of defensive activation.

METHODS

Defensive mobilization to anticipated threat was investigated in 73 patients with a primary diagnosis of PD with agoraphobia (PDA) and 52 healthy control subjects. Threat of symptom provocation was established by a standardized hyperventilation task and contrasted to threat of shock to the forearm of the participant.

RESULTS

Patients with PDA and healthy control subjects did not differ in their defensive responses during anticipation of shock. In contrast, patients with severe PDA as compared with healthy control subjects exhibited increased defensive response mobilization and reported more anxiety and panic symptoms during anticipation of feared body symptoms. Moreover, startle potentiation during anticipation of hyperventilation covaried with the severity of panic symptomatology.

CONCLUSIONS

The present findings suggest that increased defensive mobilization during anticipation of body symptoms is a neurobiological correlate of severe PDA that should be specifically targeted in PD interventions and might be used to monitor treatment success.

Methodological and clinical challenges associated with biomarkers for psychiatric disease: A scoping review

Over the past decade, psychiatric research has been on an important hunt for biomarkers of psychiatric disease. In psychiatry, the term "biomarker" is a broad umbrella term used to identify any biological variable that can be objectively measured and applied to a diagnosis; this includes genetic and epigenetic assessments, hormone levels, measures of neuro-anatomy and many other scientific modalities. However, despite hundreds of studies on the topic being published yearly and other medical specialties having success in discovering biomarkers, clinical psychiatric practice has not had the same success. This paper aims to consolidate the many opinions on the search for psychiatric biomarkers to suggest key methodological and clinical challenges that psychiatric biomarker research faces. Psychiatry as a specialty has many fundamental differences compared to other medical specialties in methods of diagnosing, underlying etiology and disease pathologies that may be limiting the success of biomarker research in itself and puts strict requirements on the research being conducted. The academic and clinical environment in which the research is being conducted also heavily influences the translation of the findings. Finally, once biomarkers are identified, more often than not they are inapplicable to clinical settings, unable to integrate into clinical practice and fail to outperform current diagnostic practices and guidelines. We also make six recommendations for more promising future research in psychiatric biomarkers.

Modelling behaviors relevant to brain disorders in the nonhuman primate: Are we there yet?

Recent years have seen a profound resurgence of activity with nonhuman primates (NHPs) to model human brain disorders. From marmosets to macaques, the study of NHP species offers a unique window into the function of primate-specific neural circuits that are impossible to examine in other models. Examining how these circuits manifest into the complex behaviors of primates, such as advanced cognitive and social functions, has provided enormous insights to date into the mechanisms underlying symptoms of numerous neurological and neuropsychiatric illnesses. With the recent optimization of modern techniques to manipulate and measure neural activity in vivo, such as optogenetics and calcium imaging, NHP research is more well-equipped than ever to probe the neural mechanisms underlying pathological behavior. However, methods for behavioral experimentation and analysis in NHPs have noticeably failed to keep pace with these advances. As behavior ultimately lies at the junction between preclinical findings and its translation to clinical outcomes for brain disorders, approaches to improve the integrity, reproducibility, and translatability of behavioral experiments in NHPs requires critical evaluation. In this review, we provide a unifying account of existing brain disorder models using NHPs, and provide insights into the present and emerging contributions of behavioral studies to the field.

Latent classes of maladaptive personality traits exhibit differences in social processing

OBJECTIVE

Social processing (SP) deficits manifest across numerous mental disorders. However, this research has been plagued by heterogeneity and a piecemeal approach whereby skills are examined in isolation rather than as part of an integrated cognitive system. Here, we combined two dimensional frameworks of psychopathology to address these limitations.

METHOD

We utilized the Alternative Model for Personality Disorders (AMPD) to distill trait-related heterogeneity within a community sample (n = 200), and the Research Domain Criteria (RDoC) 'Systems for Social Processes' to comprehensively assess SP. We first applied latent class analyses (LCA) to derive AMPD-based groups and subsequently contrasted the performance of these groups on a SP test battery that we developed to align with the RDoC SP constructs.

RESULTS

Our LCA yielded four distinct subgroups. The recognizable trait profiles and psychopathological symptoms of these classes suggested they were clinically meaningful. The subgroups differed in their SP profiles: one displayed deficits regarding the self, a second displayed deficits in understanding others, a third displayed more severe deficits including affiliation problems, whilst the fourth showed normal performance.

CONCLUSIONS

Our results support the link between clusters of maladaptive personality traits and distinctive profiles of SP deficits, which may inform research on disorders involving SP dysfunctions.

Conducting EEG research in clinically anxious preschoolers: A pilot study and preliminary recommendations

Electroencephalography (EEG) data collection can be challenging in preschoolers with anxiety who are often debilitated by fear of the unknown. Thus, we iteratively refined techniques for EEG collection in three cohorts of children with anxiety enrolled in our study of a novel intervention. Techniques involved directing child attention away from the EEG setup (Cohort 1, N = 18), open discussion of equipment and processes during setup (Cohort 2, N = 21), and a preparatory EEG-exposure session prior to data collection (Cohort 3, N = 6). Children (N = 45, 4-7 years) attempted a Time 1 EEG before intervention, and those who completed intervention (N = 28) were invited to a Time 2 EEG. The percentages who provided analyzable EEGs were assessed by cohort. Cohort 3 provided more Time 1 EEGs (83.3%) than Cohorts 1 or 2 (66.7% each), suggesting that the preparatory session supported first-time EEG collection. More children provided Time 2 EEG data across successive cohorts (Cohort 1: 66.7%, Cohort 2: 82%, Cohort 3: 100%), suggesting that more open communication facilitated repeat EEG collection. Ultimately, increased EEG exposure and child-friendly communication about procedures improved data acquisition in this sample of clinically anxious preschoolers. Detailed study procedures are shared to support future EEG research in young children with anxiety.

Range-Adaptive Value Representation in Different Stages of Schizophrenia: A Proof of Concept Study

Amotivation is related to value representation. A comprehensive account of amotivation requires a mechanistic understanding of how the brain exploits external information to represent value. To achieve maximal value discriminability, brain valuation system will dynamically adapt its coding sensitivity to the range of values available in any given condition, so-called range adaptive coding. We administered an experimental task to 30 patients with chronic schizophrenia (C-SCZ), 30 first-episode schizophrenia (FE-SCZ), 34 individuals with high social anhedonia (HSoA), and their paired controls to assess range adaptation ability. C-SCZ patients exhibited over-adaptation and their performances were negatively correlated with avolition symptoms and positive symptoms and positively correlated with blunted-affect symptoms and self-reported consummatory interpersonal pleasure scores, though the results were non-significant. FE-SCZ patients exhibited reduced adaptation, which was significantly and negatively correlated with avolition symptoms and positively correlated with the overall proportion of choosing to exert more effort. Although HSoA participants exhibited comparable range adaptation to controls, their performances were significantly and negatively correlated with the proportion of choosing to exert more effort under the lowest value condition. Our results suggest that different stages of schizophrenia spectrum showed distinct range adaptation patterns. Range adaptation impairments may index a possible underlying mechanism for amotivation symptoms in FE-SCZ and more complicated and pervasive effects on clinical symptoms in C-SCZ.

Fronto-limbic neural variability as a transdiagnostic correlate of emotion dysregulation

Emotion dysregulation is central to the development and maintenance of psychopathology, and is common across many psychiatric disorders. Neurobiological models of emotion dysregulation involve the fronto-limbic brain network, including in particular the amygdala and prefrontal cortex (PFC). Neural variability has recently been suggested as an index of cognitive flexibility. We hypothesized that within-subject neural variability in the fronto-limbic network would be related to inter-individual variation in emotion dysregulation in the context of low affective control. In a multi-site cohort (N = 166, 93 females) of healthy individuals and individuals with emotional dysregulation (attention deficit/hyperactivity disorder (ADHD), bipolar disorder (BD), and borderline personality disorder (BPD)), we applied partial least squares (PLS), a multivariate data-driven technique, to derive latent components yielding maximal covariance between blood-oxygen level-dependent (BOLD) signal variability at rest and emotion dysregulation, as expressed by affective lability, depression and mania scores. PLS revealed one significant latent component (r = 0.62, p = 0.044), whereby greater emotion dysregulation was associated with increased neural variability in the amygdala, hippocampus, ventromedial, dorsomedial and dorsolateral PFC, insula and motor cortex, and decreased neural variability in occipital regions. This spatial pattern bears a striking resemblance to the fronto-limbic network, which is thought to subserve emotion regulation, and is impaired in individuals with ADHD, BD, and BPD. Our work supports emotion dysregulation as a transdiagnostic dimension with neurobiological underpinnings that transcend diagnostic boundaries, and adds evidence to neural variability being a relevant proxy of neural efficiency.

Disentangling emotional processing in dysphoria: An ERP and cardiac deceleration study

The present study aimed to investigate emotional processing in dysphoria. To this end, the amplitude of the Late Positive Potential (LPP) and cardiac deceleration were assessed during the passive viewing of affective (pleasant, neutral, and unpleasant) pictures in 26 individuals with dysphoria and in 25 non-depressed controls. The group with dysphoria revealed a smaller LPP amplitude than the group without dysphoria in response to pleasant and neutral, but not unpleasant, stimuli at centro-parieto-occipital sites. Interestingly, whereas both groups showed cardiac deceleration when viewing pleasant compared to neutral pictures (3-6 s time window), only individuals with dysphoria showed a prolonged cardiac deceleration in response to unpleasant stimuli as compared with neutral ones. This study suggests that dysphoria is characterized by reduced motivated attentional allocation to positive information and by sustained intake of unpleasant information. Overall, the present findings provide novel insights into the characterization of valence-specific attentional processes in dysphoria as potential vulnerability factors for clinically significant depression.

Emotional cognition subgroups in mood disorders: Associations with familial risk

Patients with mood disorders show heterogeneity in non-emotional cognition. However, it is unclear whether emotional cognition (EC) is characterised by similar heterogeneity. We aimed to investigate the heterogeneity in EC among remitted patients with mood disorders and explore its association with familial risk. Data from 269 partially or fully remitted patients with mood disorders, 87 of their unaffected relatives (UR) and 203 healthy controls (HC) were pooled from two cohort studies. Hierarchical cluster analysis was conducted using the EC data from patients. UR were categorised into groups consistent with their affected relatives' cluster assignment. Clusters were compared to HC on EC, non-emotional cognition, clinical characteristics and functioning.  We identified three clusters: an 'emotionally preserved' (57%), an 'emotionally blunted' (26%) and an 'emotionally volatile' cluster (17%). 'Emotionally blunted' and 'emotionally volatile' patients also presented more deficits in non-emotional cognition (global cognition read z=-0.3 and -0.5 respectively). Relatives of 'emotionally preserved' patients were more successful at dampening negative emotions (p=.01, d=0.39, 95% CI [-0.76,-0.09]), whereas UR of 'emotionally impaired' patients underperformed in verbal fluency (p=.03, d=0.46, 95% CI [.03, 0.68]) compared to HC. The existence of impaired EC groups in remitted mood disorder highlights a need to screen for and treat EC in mood disorders. Improved ability to dampen emotions in UR of 'emotionally preserved' patients may reflect a resilience marker while impaired verbal fluency in UR of 'emotionally impaired' patients may reflect distinct genetic risk profiles in these EC subgroups.

Identification of transdiagnostic psychiatric disorder subtypes using unsupervised learning

Psychiatric disorders show heterogeneous symptoms and trajectories, with current nosology not accurately reflecting their molecular etiology and the variability and symptomatic overlap within and between diagnostic classes. This heterogeneity impedes timely and targeted treatment. Our study aimed to identify psychiatric patient clusters that share clinical and genetic features and may profit from similar therapies. We used high-dimensional data clustering on deep clinical data to identify transdiagnostic groups in a discovery sample (N = 1250) of healthy controls and patients diagnosed with depression, bipolar disorder, schizophrenia, schizoaffective disorder, and other psychiatric disorders. We observed five diagnostically mixed clusters and ordered them based on severity. The least impaired cluster 0, containing most healthy controls, showed general well-being. Clusters 1-3 differed predominantly regarding levels of maltreatment, depression, daily functioning, and parental bonding. Cluster 4 contained most patients diagnosed with psychotic disorders and exhibited the highest severity in many dimensions, including medication load. Depressed patients were present in all clusters, indicating that we captured different disease stages or subtypes. We replicated all but the smallest cluster 1 in an independent sample (N = 622). Next, we analyzed genetic differences between clusters using polygenic scores (PGS) and the psychiatric family history. These genetic variables differed mainly between clusters 0 and 4 (prediction area under the receiver operating characteristic curve (AUC) = 81%; significant PGS: cross-disorder psychiatric risk, schizophrenia, and educational attainment). Our results confirm that psychiatric disorders consist of heterogeneous subtypes sharing molecular factors and symptoms. The identification of transdiagnostic clusters advances our understanding of the heterogeneity of psychiatric disorders and may support the development of personalized treatments.

Predictive protein markers for depression severity in mood disorders: A preliminary trans-diagnostic approach study

Depression is a common symptom of many mental disorders, especially major depressive disorder (MDD) and bipolar disorder (BD). Previous studies have reported that these diseases share common pathophysiological pathways; therefore, this study elucidated whether the plasma levels of protein markers related to common depressive symptoms differed between patients with BD and those with MDD. Plasma samples of 71 patients with mood disorders and clinical manifestations were analyzed in this study. After depleting the abundant proteins, liquid chromatography-tandem mass spectrometry and label-free quantification were performed. Five proteins, viz., cholesteryl ester transfer protein (CETP), apolipoprotein D (APOD), mannan-binding lectin serine protease 2 (MASP2), Ig lambda chain V-II region BO (IGLV2-8) and Ig kappa chain V-III region NG9 (IGKV3-20) were negatively associated with the total scores of the Hamilton depression rating scale (HAM-D), after adjusting for the covariates. CETP and APOD also showed significant negative correlations with the anhedonia/retardation and guilt/agitation scores of the HAM-D. Four proteins, namely, Ig kappa chain V-II region TEW (IGKC; IGKV2D-28), Ig lambda variable 5-45 (IGLV5-45), complement factor H (CFH) and attractin (ATRN), showed significant associations with anhedonia/retardation after adjusting for covariates. Proteins that significantly correlated with the symptoms could predict the remission state of depression (area under the curve [AUC], 0.83) and anhedonia/retardation (AUC, 0.80). Bioinformatics analysis revealed that complement activation, immune response, and lipid metabolism were significantly enriched pathways. Although our study design was cross-sectional and no controls were included, protein markers identified in this preliminary study will be further investigated in our subsequent longitudinal study.

Child neurocognitive functioning influences the effectiveness of specific techniques in behavioral teacher training for ADHD: Moderator analyses from a randomized controlled microtrial

Background

Childhood attention-deficit/hyperactivity disorder (ADHD) is associated with several neurocognitive impairments. Whether these impairments influence the effectiveness of techniques that are commonly used in behavioral teacher training for ADHD has not been investigated so far.

Method

In this microtrial, teachers of 90 children with ADHD symptoms (6-12 years) were randomly assigned to a short intervention consisting of either antecedent-based (stimulus-control) techniques or consequent-based (contingency management) techniques, or to a waitlist control condition. Primary outcome was the daily assessment of individually selected problem behavior, assessed pre- and post-intervention. Potential neurocognitive moderators of treatment effect included teacher ratings of cognitive control, reward, and punishment sensitivity, and measures derived from computerized neurocognitive tasks, including attentional lapses, interference control, visuospatial working memory, and emotional functioning. Intervention condition by moderator interactions were assessed in separate multilevel mixed models.

Results

Lapses of attention, working memory, and emotional functioning interacted with intervention effectiveness. Antecedent-based techniques were effective independent of these neurocognitive functions; consequent-based techniques were (more) effective when these functions were more impaired. The effectiveness of techniques was neither related to interference control nor to teacher-rated neurocognitive functioning.

Conclusions

This study showed that child neurocognitive functioning influences the effectiveness of behavioral teacher techniques for children with ADHD symptoms. Findings suggest that antecedent-based techniques may be effective for all children, while consequent-based techniques have added value particularly for children who suffer from low visuospatial working memory, low emotional functioning, and/or large numbers of attentional lapses.

How to Design a Relevant Corpus for Sleepiness Detection Through Voice?

This article presents research on the detection of pathologies affecting speech through automatic analysis. Voice processing has indeed been used for evaluating several diseases such as Parkinson, Alzheimer, or depression. If some studies present results that seem sufficient for clinical applications, this is not the case for the detection of sleepiness. Even two international challenges and the recent advent of deep learning techniques have still not managed to change this situation. This article explores the hypothesis that the observed average performances of automatic processing find their cause in the design of the corpora. To this aim, we first discuss and refine the concept of sleepiness related to the ground-truth labels. Second, we present an in-depth study of four corpora, bringing to light the methodological choices that have been made and the underlying biases they may have induced. Finally, in light of this information, we propose guidelines for the design of new corpora.

[Introduction to the hierarchical taxonomy of psychopathology]

INTRODUCTION

In clinical practice, the usefulness of diagnosis based on the Diagnostic or Statistical Manual of Mental Disorders (DSM) or the International Classification of Diseases, 11th edition, appears essential from a clinical, research, epidemiological, administrative, economic and political level. However, such diagnostic systems have shortcomings in terms of validity, little consideration of comorbidities and strong intra-class heterogeneity. On a structural level, the operationalization of its criteria is based on a reliability which has been defined a posteriori and which does not lead to improving the validity of the diagnosis but rather to the reification of the diagnostic categories.

METHODS

First published in its current form in 2017, the Hierarchical Taxonomy of Psychopathology (HiTOP) constitutes a nosological alternative based on statistics. It conceptualizes psychopathology as a set of hierarchical dimensions, i.e. in "transdiagnostic" continua. The HiTOP is structured according to super-spectra, spectra, sub-factors, syndromes, components and symptoms. This comes from the current dimensional psychology and quantitative nosology. This article describes the basic principles of the HiTOP project and its potential to integrate into clinical and psychiatric research based on its advantages and limitations.

RESULTS

Unlike the DSM, which is descriptive and categorical, the HiTOP is first a dimensional classification. This dimensionality describes psychiatric phenomena on continua, each dimension providing a diagnostic continuum to situate a clinical patient. This dimensionality avoids the reification of categories and it limits the dichotomy between normal and pathological. In addition, HiTOP shows a hierarchical structure: vertical refinement of dimensions allows to circumvent the problem of comorbidities, proposes a new conception of etiopathogenic mechanisms, and improves management of care.

DISCUSSION

Thus, we provide an illustration of the applications of a dimensional and hierarchical classification in current clinical practice and scientific research, compared to traditional nosology. The challenges of the HiTOP arise in terms of validity, i.e. in the relation of dimensions with physiopathological mechanisms, in clinical terms, i.e. in the potential contribution of dimensions in relation to categories. Moreover, methodological challenges will be important given the inherent limitations of the HiTOP.

CONCLUSION

The HiTOP allows to examine the conceptualization of psychiatric disorders, the search for explanatory mechanisms, and treatment from another perspective for psychiatry.

Striving toward translation: strategies for reliable fMRI measurement

fMRI has considerable potential as a translational tool for understanding risk, prioritizing interventions, and improving the treatment of brain disorders. However, recent studies have found that many of the most widely used fMRI measures have low reliability, undermining this potential. Here, we argue that many fMRI measures are unreliable because they were designed to identify group effects, not to precisely quantify individual differences. We then highlight four emerging strategies [extended aggregation, reliability modeling, multi-echo fMRI (ME-fMRI), and stimulus design] that build on established psychometric properties to generate more precise and reliable fMRI measures. By adopting such strategies to improve reliability, we are optimistic that fMRI can fulfill its potential as a clinical tool.

Deconstructing Apathy in Parkinson's Disease: Challenges in Isolating Core Components of Apathy From Depression, Anxiety, and Fatigue

Apathy, fatigue and depression are amongst the most debilitating non-motor syndromes of Parkinson's disease (PD). The aim of this study was to examine the prevalence of apathy, depression, anxiety and fatigue and whether these syndromes are separable in PD. A total of 337 patients were examined using the Unified Parkinson's Disease Rating Scale (UPDRS part III), the Apathy Evaluation Scale, the Hospital Anxiety and Depression Scale and the Fatigue Severity Scale. Using standard cutoff criteria, the prevalence rates of significant apathy, mild-to-severe depression, mild-to-severe anxiety and severe fatigue were 23.7, 13.4, 15.4, and 17.8%, respectively. Next, confirmatory factor analysis was employed of items from these three clinical scales. A priori hypothesis testing including four different factors (reduced motivation/interest, physical fatigue, reduced pleasure, anxiety) was performed. The factor analysis revealed strong fit statistics for the model with χ2 (57, N = 377) = 58.9, p = 0.41, CMIN/DF = 1,034, NFI = 0.977, CFI = 0.999, IFI = 0.999, RFI = 0.968, and TLI = 0.999. The RMSEA was 0.01, and the standardized RMR was 0.027. These results support the hypothesis that apathy, fatigue, depression and anxiety represent prevalent syndromes that can be separated in Parkinson's disease and that apathy is not just a subcomponent of depression or fatigue. The results of this study may contribute to a clearer diagnostic process for apathy, fatigue and depression and may aid in patient care.

Increased pupil dilation to happy faces in children with hyperactive/impulsive symptoms of ADHD

Attention-deficit/hyperactivity disorder (ADHD) is associated with disrupted emotional processes including impaired regulation of approach behavior and positive affect, irritability, and anger. Enhanced reactivity to emotional cues may be an underlying process. Pupil dilation is an indirect index of arousal, modulated by the autonomic nervous system and activity in the locus coeruleus-noradrenergic system. In the current study, pupil dilation was recorded while 8- to 12- year old children (n = 71, 26 with a diagnosis of ADHD and 45 typically developing), viewed images of emotional faces. Parent-rated hyperactive/impulsive symptoms were uniquely linked to higher pupil dilation to happy, but not fearful, angry, or neutral faces. This was not explained by comorbid externalizing symptoms. Together, these results suggest that hyperactive/impulsive symptoms are associated with hyperresponsiveness to approach-related emotional cues across a wide range of symptom severity.

Neural Correlates of Affective Stimulus Evaluation: A Case-by-Case Analysis

A recent study provided first evidence that neural correlates of affective stimulus evaluation, that is, the early posterior negativity (EPN) and late positive potential (LPP), can be assessed at the individual case level. Expanding the case-by-case approach, the main aim of the present study was to explore the process of affective stimulus evaluation within the individual participant with respect to multiple emotional stimulus classes. Towards this end, each participant viewed separate blocks of low and high arousing pictures from behavior systems of predator fear, disease avoidance, and sexual reproduction. 13 out of 16 participants showed larger EPN and LPP amplitudes for higher than lower arousing stimuli for all three behavior systems. Furthermore, rather than indicating a general lack of emotional modulation, cases of non-significant EPN (N= 3) and LPP (N= 2) tests in individual participants appeared to be specific to a single emotion category. Overall, assessing the emotional modulation of the EPN and LPP across multiple behavior systems strengthens the case-by-case approach regarding an effect "common-to-all" as well as by differentiating non-significant effects within individuals in terms of a content-specific or general phenomenon. Implications for revealing a general principle of emotion functioning and biomarker development are discussed.

The Monash Autism-ADHD genetics and neurodevelopment (MAGNET) project design and methodologies: a dimensional approach to understanding neurobiological and genetic aetiology

Background

ASD and ADHD are prevalent neurodevelopmental disorders that frequently co-occur and have strong evidence for a degree of shared genetic aetiology. Behavioural and neurocognitive heterogeneity in ASD and ADHD has hampered attempts to map the underlying genetics and neurobiology, predict intervention response, and improve diagnostic accuracy. Moving away from categorical conceptualisations of psychopathology to a dimensional approach is anticipated to facilitate discovery of data-driven clusters and enhance our understanding of the neurobiological and genetic aetiology of these conditions. The Monash Autism-ADHD genetics and neurodevelopment (MAGNET) project is one of the first large-scale, family-based studies to take a truly transdiagnostic approach to ASD and ADHD. Using a comprehensive phenotyping protocol capturing dimensional traits central to ASD and ADHD, the MAGNET project aims to identify data-driven clusters across ADHD-ASD spectra using deep phenotyping of symptoms and behaviours; investigate the degree of familiality for different dimensional ASD-ADHD phenotypes and clusters; and map the neurocognitive, brain imaging, and genetic correlates of these data-driven symptom-based clusters.

Methods

The MAGNET project will recruit 1,200 families with children who are either typically developing, or who display elevated ASD, ADHD, or ASD-ADHD traits, in addition to affected and unaffected biological siblings of probands, and parents. All children will be comprehensively phenotyped for behavioural symptoms, comorbidities, neurocognitive and neuroimaging traits and genetics.

Conclusion

The MAGNET project will be the first large-scale family study to take a transdiagnostic approach to ASD-ADHD, utilising deep phenotyping across behavioural, neurocognitive, brain imaging and genetic measures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13229-021-00457-3.