Psychopathology research in the RDoC era: Unanswered questions and the importance of the psychophysiological unit of analysis

The absurdity of the latent disease model in mental health: 10,130,814 ways to have a DSM-5-TR psychological disorder

BACKGROUND

Latent disease classification is currently the accepted approach to mental illness diagnosis. In the United States, this takes the form of the Diagnostic and Statistical Manual of Mental Disorders-5-Text Revision (DSM-5-TR). Latent disease classification has been criticized for reliability and validity problems, particularly regarding diagnostic heterogeneity. No authors have calculated the scope of the heterogeneity problem of the entire DSM-5-TR.

AIMS

We addressed this issue by calculating the unique diagnostic profiles that exist for every DSM-5-TR diagnosis.

METHODS

We did this by applying formulas previously used in smaller heterogeneity analyses to all diagnoses within the DSM-5-TR.

RESULTS

We found that there are 10,130,814 ways to be diagnosed with a mental illness using DSM-5-TR criteria. When specifiers are considered, this number balloons to over 161 septillion unique diagnostic presentations (driven mainly by bipolar II disorder). Additionally, there are 1,951,065 ways to present with psychiatric symptoms, yet not meet diagnostic criteria.

CONCLUSIONS

Latent disease classification leads to considerable heterogeneity in possible presentations. We provide examples of how latent disease classification harms research and treatment programs. We echo recommendations for the dismissal of latent disease classification as a mental illness diagnostic program.

Preliminary evidence that individuals with remitted alcohol use disorder and major depressive disorder exhibit enhanced neural responses to reward: An EEG study

INTRODUCTION

Disruptions in neural responses to reward are implicated in risk for Alcohol Use Disorder (AUD) and Major Depressive Disorder (MDD). It is not clear whether these findings extend to those in remission from AUD and MDD, a critical question as studies of remission can (a) rule out effects due to current symptoms, and (b) can reveal potential trait-like differences.

METHODS

Individuals with and without remitted AUD (rAUD) and/or rMDD (rMDD) were drawn from a larger study to create four groups: rAUD (n = 54), rMDD (n = 66), rAUD + rMDD (n = 53), and a community control group (CCG; n = 81). Participants completed a validated monetary reward task during electroencephalogram (EEG). Multilevel models examined group differences in event-related potentials and time-frequency indices of reward and loss responsiveness, namely, reward positivity (RewP), feedback negativity (FN), reward-related delta power, and loss-related theta power.

RESULTS

Analyses revealed that the rAUD + rMDD group had significantly higher reward-related delta activity than the three other groups (p-values < 0.01), which did not differ from each other. Sensitivity analyses revealed this relationship fell just above the threshold set for significance after controlling for residual current MDD and AUD symptoms (p =.05). There were no other group differences or significant interactions (p-values > 0.05).

CONCLUSIONS

To our knowledge, this is the first study to show that individuals with remitted AUD and MDD demonstrate increased sensitivity to rewards compared to individuals with remitted AUD alone, MDD alone, and without AUD or MDD. These findings suggest heightened motivational salience to reward might be an important factor in comorbid AUD and MDD.

Familial risk for depression is associated with reduced P300 and late positive potential to affective stimuli and prolonged cardiac deceleration to unpleasant stimuli

Despite evidence of abnormal affective processing as a key correlate of depression, specific attentional mechanisms underlying processing of emotions in familial risk for depression have yet to be investigated in a single study. To this end, the amplitude of the P300 and late positive potential (LPP) complex and cardiac deceleration were assessed during the passive viewing of affective pictures in 32 individuals who had family history of depression (without depressive symptoms) and in 30 controls (without depressive symptoms and family history of depression). Individuals with familial risk for depression revealed reduced P300-LPP amplitudes in response to pleasant and unpleasant stimuli relative to controls, and comparable P300-LPP amplitudes in response to pleasant and neutral stimuli. Controls, but not individuals with familial risk for depression, reported cardiac deceleration during the viewing of pleasant vs. neutral and unpleasant stimuli in the 0-3 s time window. Also, only individuals with familial risk for depression showed a prolonged cardiac deceleration in response to unpleasant vs. neutral stimuli. Overall, the present study provides new insights into the characterization of emotion-related attentional processes in familial risk for depression as potential vulnerability factors for the development of the disorder.

Rethinking the risk for depression using the RDoC: A psychophysiological perspective

Considering that the classical categorical approach to mental disorders does not allow a clear identification of at-risk conditions, the dimensional approach provided by the Research Domain Criteria (RDoC) is useful in the exploration of vulnerability to psychopathology. In the RDoC era, psychophysiological models have an important role in the reconceptualization of mental disorders. Indeed, progress in the study of depression vulnerability has increasingly been informed by psychophysiological models. By adopting an RDoC lens, this narrative review focuses on how psychophysiological models can be used to advance our knowledge of the pathophysiological mechanisms underlying depression vulnerability. Findings from psychophysiological research that explored multiple RDoC domains in populations at-risk for depression are reviewed and discussed. Future directions for the application of psychophysiological research in reaching a more complete understanding of depression vulnerability and, ultimately, improving clinical utility, are presented.

The interplay of childhood maltreatment and maternal depression in relation to the reward positivity in youth

Guided by developmental psychopathology and dual-risk frameworks, the present study examined the interplay between childhood maltreatment and maternal major depression history in relation to neural reward responsiveness in youth. The sample consisted of 96 youth (ages 9-16; M = 12.29 years, SD = 2.20; 68.8% female) drawn from a large metropolitan city. Youth were recruited based on whether their mothers had a history of major depressive disorder (MDD) and were categorized into two groups: youth with mothers with a history of MDD (high risk; HR; n = 56) and youth with mothers with no history of psychiatric disorders (low risk; LR; n = 40). The reward positivity (RewP), an event-related potential component, was utilized to measure reward responsiveness and the Childhood Trauma Questionnaire measured childhood maltreatment. We found a significant two-way interaction between childhood maltreatment and risk group in relation to RewP. Simple slope analysis revealed that in the HR group, greater childhood maltreatment was significantly associated with reduced RewP. The relationship between childhood maltreatment and RewP was not significant among the LR youth. The present findings demonstrate that the association between childhood maltreatment and blunted reward responsiveness is dependent on whether offspring have mothers with histories of MDD.

Putamen Structure and Function in Familial Risk for Depression: A Multimodal Imaging Study

BACKGROUND

The putamen has been implicated in depressive disorders, but how its structure and function increase depression risk is not clearly understood. Here, we examined how putamen volume, neuronal density, and mood-modulated functional activity relate to family history and prospective course of depression.

METHODS

The study includes 115 second- and third-generation offspring at high or low risk for depression based on the presence or absence of major depressive disorder in the first generation. Offspring were followed longitudinally using semistructured clinical interviews blinded to their familial risk; putamen structure, neuronal integrity, and functional activation were indexed by structural magnetic resonance imaging (MRI), proton magnetic resonance spectroscopy (N-acetylaspartate/creatine ratio), and functional MRI activity modulated by valence and arousal components of a mood induction task, respectively.

RESULTS

After adjusting for covariates, the high-risk individuals had lower putamen volume (standardized betas, β-left = -0.17, β-right = -0.15, ps = .002), N-acetylaspartate/creatine ratio (β-left= -0.40, β-right= -0.37, ps < .0001), and activation modulated by valence (β-left = -0.22, β-right = -0.27, ps < .05) than low-risk individuals. Volume differences were greater at younger ages, and N-acetylaspartate/creatine ratio differences were greater at older ages. Lower putamen volume also predicted major depressive disorder episodes up to 8 years after the scan (β-left = -0.72, p = .013; β-right = -0.83, p = .037). Magnetic resonance spectroscopy and task functional MRI measures were modestly correlated (0.27 ≤ r ≤ 0.33).

CONCLUSIONS

Findings demonstrate abnormalities in putamen structure and function in individuals at high risk for major depressive disorder. Future studies should focus on this region as a potential biomarker for depressive illness, noting meanwhile that differences attributable to family history may peak at different ages based on which MRI modality is being used to assay them.

Pathways to depression: Dynamic associations between neural responses to appetitive cues in the environment, stress, and the development of illness

This review focuses on research my colleagues and I have conducted on etiological pathways to depression. Much of this work has focused on the measurement of neural responses to appetitive cues, using two event-related brain potential (ERP) components, the Late Positive Potential (LPP) and the Reward Positivity (RewP). Reductions in each of these components have been associated with current symptoms of depression, and in some cases have been shown to differentiate anxious from depressive phenotypes. In this review, I will describe three broad and related approaches we have taken in our research to address a series of interdependent issuess. The first attempts to understand different sources of variation in the LPP and RewP, and how these sources interact with one another. The second tries to identify whether variation in the processes measured by these ERP components might reflect a latent vulnerability to depression and its symptoms, that is evident prior to illness onset. And the third examines the possibility that the processes reflected in the LPP and RewP might play a mechanistic role in the development of depression.

Using what we know about threat reactivity models to understand mental health during the COVID-19 pandemic

The COVID-19 pandemic has been accompanied by unprecedented levels of stress and threats in a variety of domains (e.g., health, livelihood). Individual differences in threat reactivity may explain why some individuals are at elevated risk for the development or maintenance of psychopathology during the COVID-19 pandemic. This article describes several prominent models, mechanisms, and components of threat reactivity (e.g., appraisals, intolerance of uncertainty, avoidance) and discusses how they might help improve understanding of changes in psychopathology during and following the COVID-19 pandemic.

Event-related potentials to acoustic startle probes during unpredictable threat are associated with individual differences in intolerance of uncertainty

Individual differences in sensitivity to unpredictable threat may be a critical mechanism for internalizing psychopathology phenotypes. The present study examined whether the startle probe-elicited N100 and P300 during unpredictable threat - two event-related potentials indexing early and elaborative attentional processing of unpredictable threat - may be endophenotypes for internalizing psychopathology, including fear and distress/misery disorders and intolerance of uncertainty (IU), a clinical trait that is transdiagnostically associated with internalizing disorders. A large sample of adult siblings (N = 375) completed the no, predictable, and unpredictable threat task, during which the N100 and P300 were recorded. Relative to the no threat condition, N100 was more strongly enhanced in anticipation of unpredictable than predictable threat while P300 was suppressed to both predictable and unpredictable threat. While neither N100 enhancement nor P300 suppression to unpredictable threat was associated with fear or distress/misery disorders, they were negatively linked to inhibitory IU (a facet of IU). Thus, individuals high in inhibitory IU showed reduced attentional engagement with the threatening context when it was unpredictable. Further, N100 enhancement and, to a lesser degree, P300 suppression to unpredictable threat showed familial aggregation - a key criterion for determining whether a biomarker is an endophenotype. In sum, N100 enhancement and P300 suppression to unpredictable threat may be endophenotypes for dimensional measures of internalizing psychopathology.

At the heart of change: Differences in young offenders' HRV patterns after the delivery of the PSYCHOPATHY.COMP program

INTRODUCTION

Literature has pointed the need for intervention programs specifically tailored to target the treatment needs of young offenders, as well as the need to test the efficacy of such programs through physiological indexes of emotion regulation (e.g., heart rate variability; HRV), complementing self-reports typically used as outcome measures. The PSYCHOPATHY.COMP is a 20-session individual intervention program based on Compassion Focused Therapy aiming to reduce psychopathic traits and disruptive behavior among young offenders through the development of a compassionate motivation, while stimulating the soothing system as a strategy to improve emotion regulation. Previous research with young offenders has shown decreases in vagally mediated HRV (vmHRV) when the soothing system is activated. This physiological pattern seems to mirror threat-like responses that contrast with relaxed states.

METHODS

To test the efficacy of the PSYCHOPATHY.COMP, a clinical trial was implemented encompassing a treatment (n = 56) and a control group (n = 53). Treatment participants attended the PSYCHOPATHY.COMP, while controls received the Treatment As Usual (TAU) delivered in Portuguese juvenile detention facilities. HRV data was collected throughout a standardized procedure (encompassing resting, reactivity and recovery phases) specifically designed to trigger the soothing system. Participants were assessed at pre-treatment, post-treatment and 6-months follow-up.

RESULTS

Although treatment participants continued to process the soothing system as unpleasant (with decreased vmHRV), they seem to become able to adaptively recover from the stimuli without avoiding it or resorting to maladaptive coping strategies. The physiological pattern was in line with participants' decreases in difficulties in emotion regulation across the assessment periods. In contrast, controls seemed to have actively employed coping strategies associated with increases in vmHRV not only when the soothing system was triggered, but also when recovering from the stimuli. Congruently, for controls, increases in difficulties in emotion regulation were found, with increases in the lack of emotional clarity across the assessment periods.

DISCUSSION

Findings offer new evidence for the efficacy of the PSYCHOPATHY.COMP program in improving emotion regulation in young offenders, assessed through both self-report and physiological measures. Additionally, findings support the assessment of the autonomic balance as a treatment efficacy index in future research, targeting the rehabilitation of these youth.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT03971682.

Ethnic differences in behavioral and physiological indicators of sensitivity to threat

The clinical presentation of anxiety may differ between Hispanics/Latinx (H/L) and non-H/L, although findings on ethnic differences in self-reported anxiety symptoms have been mixed. Fewer studies have focused on ethnic differences in quick and relatively automatic laboratory-assessed indicators of anxiety symptoms, which have the potential to be more objective indicators than self-report. Therefore, the present study examined ethnic differences in two laboratory-assessed indicators of threat sensitivity (an important transdiagnostic mechanism of anxiety): attentional bias to threat and electromyography startle reactivity to threat. White H/L (n = 117) and White non-H/L (n = 168) adults who were matched on demographics and lifetime psychopathology (including anxiety) completed a dot-probe task to assess attentional bias to threat and the No-Predictable-Unpredictable threat (NPU) task to assess startle reactivity to threat. Results indicated that H/L displayed less Slow OrientationRB (β = -0.27, p = 0.032, R2β∗ = 0.02), and increased Slow DisengagementRB (β = 0.31, p = 0.016, R2β∗ = 0.02) compared to non-H/L. H/L exhibited blunted overall startle compared to non-H/L (β = -0.30, p = 0.014, R2β∗ = 0.02), but groups did not differ in startle reactivity to either predictable or unpredictable threat. In summary, H/L and non-H/L may differ in their experience and presentation of anxiety symptoms and such differences may vary across indicators of sensitivity to threat.

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 centrality of temperament to the research domain criteria (RDoC): The earliest building blocks of psychopathology

The research domain criteria (RDoC) is an innovative approach designed to explore dimensions of human behavior. The aim of this approach is to move beyond the limits of psychiatric categories in the hope of aligning the identification of psychological health and dysfunction with clinical neuroscience. Despite its contributions to adult psychopathology research, RDoC undervalues ontogenetic development, which circumscribes our understanding of the etiologies, trajectories, and maintaining mechanisms of psychopathology risk. In this paper, we argue that integrating temperament research into the RDoC framework will advance our understanding of the mechanistic origins of psychopathology beginning in infancy. In illustrating this approach, we propose the incorporation of core principles of temperament theories into a new "life span considerations" subsection as one option for infusing development into the RDoC matrix. In doing so, researchers and clinicians may ultimately have the tools necessary to support emotional development and reduce a young child's likelihood of psychological dysfunction beginning in the first years of life.

Cross-cultural adaptation and psychometric evaluation of the Brazilian version of the Temporal Experience of Pleasure Scale (TEPS-Br)

INTRODUCTION

Anhedonia is a critical symptom of major depressive disorder that is defined as the reduced ability to experience pleasure. The Temporal Experience of Pleasure Scale (TEPS) is commonly used to measure anhedonia and has exhibited satisfactory reliability.

OBJECTIVES

We aim to perform cross-cultural adaptation of a Brazilian version of the TEPS and evaluate its psychometric properties.

METHOD

The cross-cultural adaptation was performed according to previously established protocols. Cronbach's alpha coefficient of internal consistency was used to establish the degree of interrelation and coherence of items. Also, we calculated the intraclass correlation coefficient to determine the stability of the scale after a proposed interval had elapsed and used exploratory factor analysis to evaluate the scale's factor structure and content validity. Principal component analysis was used to determine the factors to be retained in the factor model.

RESULTS

The participants reported that the Brazilian version of the TEPS had good comprehensibility and applicability. The results revealed a statistically significant correlation between measures. The intraclass correlation coefficient calculated was significant. The Cronbach's alpha value calculated indicated that the scale's overall internal consistency was adequate.

CONCLUSION

The Portuguese version of the TEPS scale proposed achieved good comprehensibility for the Brazilian population and its psychometric characteristics demonstrated good reliability and validity.

Evaluating the criterion validity of hierarchical psychopathology dimensions across models: Familial aggregation and associations with research domain criteria (sub)constructs

The Hierarchical Taxonomy of Psychopathology (HiTOP) posits that psychopathology is a hierarchy of correlated dimensions. Numerous studies have examined the validity of these dimensions using bifactor models, in which each disorder loads onto both a general and specific factor (e.g., internalizing, externalizing). Although bifactor models tend to fit better than alternative models, concerns have been raised about bifactor model selection, factor reliability, and interpretability. Therefore, we compared the reliability and validity of several higher-order HiTOP dimensions between bifactor and correlated factor models using familial aggregation and associations with Research Domain Criteria (RDoC; sub)constructs as validators. Lifetime psychopathology was assessed in a community sample (N = 504) using dimensional disorder severity scales calculated from semistructured interview data. A series of unidimensional, correlated factor, and bifactor models were fit to model several HiTOP dimensions. A bifactor model with two specific factors (internalizing and disinhibited externalizing) and a correlated two-factor model provided the best fit to the data. HiTOP dimensions had adequate reliability in the correlated factor model, but suboptimal reliability in the bifactor model. The disinhibited externalizing dimension was highly correlated across the two models and was familial, yet largely unrelated to RDoC (sub)constructs in both models. The internalizing dimension in the correlated factor model and the general factor in the bifactor model were highly correlated and had similar validity patterns, suggesting the general factor was largely redundant with the internalizing dimension in the correlated factor model. These findings support concerns about the interpretability of psychopathology dimensions in bifactor models. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Is Low Heart Rate Variability Associated with Emotional Dysregulation, Psychopathological Dimensions, and Prefrontal Dysfunctions? An Integrative View

Several studies have suggested a correlation between heart rate variability (HRV), emotion regulation (ER), psychopathological conditions, and cognitive functions in the past two decades. Specifically, recent data seem to support the hypothesis that low-frequency heart rate variability (LF-HRV), an index of sympathetic cardiac control, correlates with worse executive performances, worse ER, and specific psychopathological dimensions. The present work aims to review the previous findings on these topics and integrate them from two main cornerstones of this perspective: Porges' Polyvagal Theory and Thayer and Lane's Neurovisceral Integration Model, which are necessary to understand these associations better. For this reason, based on these two approaches, we point out that low HRV is associated with emotional dysregulation, worse cognitive performance, and transversal psychopathological conditions. We report studies that underline the importance of considering the heart-brain relation in order to shed light on the necessity to implement psychophysiology into a broader perspective on emotions, mental health, and good cognitive functioning. This integration is beneficial not only as a theoretical ground from which to start for further research studies but as a starting point for new theoretical perspectives useful in clinical practice.

The emotion-elicited late positive potential is stable across five testing sessions

Many studies have examined associations between neural and behavioral markers of attention to emotion and individual differences in affective functioning. However, the majority of these studies are cross-sectional, and examine associations between brain, behavior, and individual differences at one or two time-points, limiting our understanding of the extent to which these neural responses reflect trait-like patterns of attention. The present study used the Emotional Interrupt paradigm, and examined the stability and trajectory of behavioral (i.e., reaction time to targets following task-irrelevant appetitive, neutral, and aversive images), and neural responses to images (i.e., the late positive potential or LPP), across five sessions separated by one week in 86 individuals. Additionally, we examined the extent to which the LPP and behavioral measures were sensitive to naturally occurring daily fluctuations in positive and negative affect. Results indicate that, though the magnitude of the conditional LPP waveforms decreased over time, the degree of emotional modulation (i.e., differentiation of emotional from neutral) did not; in fact, differentiation of appetitive from neutral increased over time. Behavioral responses were similarly stable across sessions. Additionally, we largely did not observe significant effects of state positive and negative affect on the LPP or behavior over time. Finally, the LPP elicited by appetitive images significantly predicted reaction time to targets following these images. These data suggest that neural and behavioral markers of attention to motivationally salient cues may be trait-like in nature, and may be helpful in future studies seeking to identify markers of vulnerability for diverse forms of psychopathology.

Collectivism is Associated with Enhanced Neural Response to Socially-Salient Errors among Adolescents

The perceived salience of errors can be influenced by individual-level motivational factors. Specifically, those who endorse a high degree of collectivism, a cultural value that emphasizes prioritization of interpersonal relationships, may find errors occurring in a social context to be more aversive than individuals who endorse collectivism to a lesser degree, resulting in upregulation of a neural correlate of error-monitoring, the error-related negativity (ERN). This study aimed to identify cultural variation in neural response to errors occurring in a social context in a sample of diverse adolescents. It was predicted that greater collectivism would be associated with enhanced neural response to errors occurring as part of a team. Participants were 95 Latinx (n = 35), Asian American (n = 20), and non-Latinx White (n = 40) adolescents (ages 13-17) who completed a go/no-go task while continuous electroencephalogram was recorded. The task included social (team) and non-social (individual) conditions. ERN was quantified using mean amplitude measures. Regression models demonstrated that collectivism modulated neural response to errors occurring in a social context, an effect that was most robust for Latinx adolescents. Understanding cultural variation in neural sensitivity to social context could inform understanding of both normative and maladaptive processes associated with self-regulation.

Cannabis users demonstrate enhanced neural reactivity to reward: An event-related potential and time-frequency EEG study

INTRODUCTION

Disruptions in neural measures of reward responsiveness are implicated in risk for and the development of Substance Use Disorders (SUDs) in general, but it is not clear if this is also true for Cannabis Use Disorder (CUD). To date, no studies have examined neural reward responsiveness in cannabis users using EEG.

METHODS

Cannabis users (CU; n = 67) and non-users (n = 60) were drawn from larger studies of individuals with and without internalizing and externalizing psychopathology. Groups were matched on current and lifetime psychopathology. Participants completed a validated monetary reward task during electroencephalogram (EEG). One-way between subject analysis of covariance (ANCOVA) models examined group differences in four EEG indicators of reward responsiveness - the reward positivity (RewP) and feedback negativity (FN) event-related potentials and two time-frequency measures (reward-related delta and loss-related theta).

RESULTS

CU demonstrated an enhanced RewP to the attainment of monetary reward compared to non-users (p = .004), even after controlling for relevant covariates. Secondary analyses found that occasional CU, but not current CUD or remitted CUD, showed enhanced RewP compared to non-users. There were no significant differences in FN, reward-related delta, or loss-related theta time-frequency measures between groups.

CONCLUSIONS

To our knowledge, this is the first study to show preliminary evidence that CU have an enhanced RewP to reward and the extent of disruption may be related to CUD status. Our findings suggest that greater neural reward responsiveness may only be seen among occasional CU, not necessarily among CU with current or remitted CUD.

Distress Tolerance as a Familial Vulnerability for Distress-Misery Disorders

Low perceived distress tolerance (DT), a trait-like individual difference factor reflecting one's perceived ability to withstand aversive affective states, has been linked with current internalizing and substance use disorders (SUDs). However, perceived DT has not been systematically evaluated as a familial, transdiagnostic vulnerability factor for internalizing and SUDs. The current study tested whether perceived DT runs in families and whether it is reduced among individuals with versus without remitted internalizing/SUD psychopathology. Perceived DT and internalizing/SUDs were measured in 638 individuals (nested within 256 families). Analyses also adjusted for the effects of neuroticism to test whether DT was a specific vulnerability factor independent of temperamental negative affect. Analyses revealed that perceived DT was lower in individuals with remitted distress (i.e., major depression, generalized anxiety disorder, posttraumatic stress disorder) but not fear disorders (i.e., panic disorder, social anxiety disorder, specific phobia, obsessive-compulsive spectrum disorders) relative to healthy controls, and the effect of distress-misery disorder history remained significant when adjusting for neuroticism. Perceived DT was not significantly different among individuals with versus without a remitted SUD. There were no effects for comorbid SUD and distress-misery disorders. Finally, perceived DT was also significantly correlated within families, suggesting that it runs in families. Overall, results suggest that independent of neuroticism, low perceived DT is a familial vulnerability for distress (but not fear or substance use) disorders.

Test-retest & familial concordance of MDD symptoms

Psychopathology research has increasingly sought to study the etiology and treatment of individual symptoms, rather than categorical diagnoses. However, it is unclear whether commonly used measures have adequate psychometric properties for assessing individual symptoms. This study examined the test-retest reliability and familial concordance (an indicator of validity) of the symptoms of Major Depressive Disorder (MDD), a disorder consisting of nine core symptoms, most of which are aggregated (e.g., symptom 7 of the DSM criteria for MDD is worthlessness or guilt). Lifetime MDD symptoms were measured in 504 young adults (237 sibling pairs) using the Structured Clinical Interview for DSM-5 (SCID). Fifty-one people completed a second SCID within three weeks of their first SCID. Results indicated that aggregated and unaggregated symptoms demonstrated moderate to substantial test-retest reliability and generally significant, but slight to fair familial concordance (with the highest familial concordance being for markedly diminished interest or pleasure and its unaggregated components - decreased interest and decreased pleasure). Given the increasing focus on the differential validity of individual MDD symptoms, the present study suggests that interview-based assessments of depression can assess most individual symptoms with adequate levels of reliability and validity.

The moderating role of externalizing problems on the association between anxiety and the error-related negativity in youth

The error-related negativity (ERN) is an event-related potential that reflects error monitoring. Enhanced ERN indicates sensitivity to performance errors and is a correlate of anxiety disorders. In contrast, youth with externalizing problems exhibit a reduced ERN, suggesting decreased error monitoring. Anxiety and externalizing problems commonly co-occur in youth, but no studies have tested how comorbidity might modulate the ERN. In a sample of youth (N = 46, ages 7-19) with and without anxiety disorders, this preliminary study examined the interactive effect of anxiety and externalizing problems on ERN. Results suggest that externalizing problems moderate the relation between anxiety symptoms and ERN in youth. Anxious youth with less externalizing problems exhibited enhanced ERN response to errors. Conversely, anxious youth with greater externalizing problems demonstrated diminished ERN in response to errors. The regions of significance and proportion affected tests indicated that the moderating the effect of externalizing problems was only significant for youth with anxiety disorders. Findings suggest that enhanced neural error sensitivity could be a specific neurophysiological marker for anxiety disorders, whereas anxious individuals with comorbid externalizing problems demonstrate reduced error monitoring, similar to those with primary externalizing pathology. Results underscore the utility of examining neural correlates of pediatric anxiety comorbidity subtypes.

Towards a Pragmatic Approach to a Psychophysiological Unit of Analysis for Mental and Brain Disorders: An EEG-Copeia for Neurofeedback

This article proposes what we call an "EEG-Copeia" for neurofeedback, like the "Pharmacopeia" for psychopharmacology. This paper proposes to define an "EEG-Copeia" as an organized list of scientifically validated EEG markers, characterized by a specific association with an identified cognitive process, that define a psychophysiological unit of analysis useful for mental or brain disorder evaluation and treatment. A characteristic of EEG neurofeedback for mental and brain disorders is that it targets a EEG markers related to a supposed cognitive process, whereas conventional treatments target clinical manifestations. This could explain why EEG neurofeedback studies encounter difficulty in achieving reproducibility and validation. The present paper suggests that a first step to optimize EEG neurofeedback protocols and future research is to target a valid EEG marker. The specificity of the cognitive skills trained and learned during real time feedback of the EEG marker could be enhanced and both the reliability of neurofeedback training and the therapeutic impact optimized. However, several of the most well-known EEG markers have seldom been applied for neurofeedback. Moreover, we lack a reliable and valid EEG targets library for further RCT to evaluate the efficacy of neurofeedback in mental and brain disorders. With the present manuscript, our aim is to foster dialogues between cognitive neuroscience and EEG neurofeedback according to a psychophysiological perspective. The primary objective of this review was to identify the most robust EEG target. EEG markers linked with one or several clearly identified cognitive-related processes will be identified. The secondary objective was to organize these EEG markers and related cognitive process in a psychophysiological unit of analysis matrix inspired by the Research Domain Criteria (RDoC) project.

Digital phenotyping of negative symptoms: the relationship to clinician ratings

Negative symptoms are a critical, but poorly understood, aspect of schizophrenia. Measurement of negative symptoms primarily relies on clinician ratings, an endeavor with established reliability and validity. There have been increasing attempts to digitally phenotype negative symptoms using objective biobehavioral technologies, eg, using computerized analysis of vocal, speech, facial, hand and other behaviors. Surprisingly, biobehavioral technologies and clinician ratings are only modestly inter-related, and findings from individual studies often do not replicate or are counterintuitive. In this article, we document and evaluate this lack of convergence in 4 case studies, in an archival dataset of 877 audio/video samples, and in the extant literature. We then explain this divergence in terms of "resolution"-a critical psychometric property in biomedical, engineering, and computational sciences defined as precision in distinguishing various aspects of a signal. We demonstrate how convergence between clinical ratings and biobehavioral data can be achieved by scaling data across various resolutions. Clinical ratings reflect an indispensable tool that integrates considerable information into actionable, yet "low resolution" ordinal ratings. This allows viewing of the "forest" of negative symptoms. Unfortunately, their resolution cannot be scaled or decomposed with sufficient precision to isolate the time, setting, and nature of negative symptoms for many purposes (ie, to see the "trees"). Biobehavioral measures afford precision for understanding when, where, and why negative symptoms emerge, though much work is needed to validate them. Digital phenotyping of negative symptoms can provide unprecedented opportunities for tracking, understanding, and treating them, but requires consideration of resolution.

The Relation Between Posttraumatic Stress Symptom Severity and Startle Potentiation to Predictable and Unpredictable Threat

Aberrant threat reactivity has been implicated in the pathophysiology of posttraumatic stress disorder (PTSD); however, the literature on this association is mixed. One factor that may contribute to this inconsistent association is differences in severity of posttraumatic stress symptoms (PTSSs) across studies, but no studies have tested this hypothesis. The relation between PTSD and threat reactivity may also differ between unpredictable threats (U-threats) and predictable threats (P-threats), given burgeoning evidence to support a particular role for aberrant responding to U-threat in PTSD. The present study examined how PTSS severity relates to startle potentiation to U-threat and P-threat in a trauma-exposed community sample (N = 258). There was a negative linear, but not quadratic, relation between PTSS severity and startle potentiation to U-threat, but not P-threat. Blunted defensive responding to U-threat may therefore contribute to higher levels of PTSSs and may represent a novel treatment target for higher levels of PTSSs.

Antisocial Disorders in Adolescence and Youth, According to Structural, Emotional, and Cognitive Transdiagnostic Variables: A Systematic Review

Transdiagnostic causal variables have been identified that have allowed understanding the origin and maintenance of psychopathologies in parsimonious explanatory models of antisocial disorders. However, it is necessary to systematize the information published in the last decade. The aim of the study was to identify through a systematic review, the structural, emotional and cognitive transdiagnostic variables in antisocial disorders of adolescence and youth. Recommendations for systematic reviews and meta-extraction and analysis of information according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA), the Cochrane Collaboration and Campbell were followed. We found 19 articles from 110 reviewed documents. The results indicated that at a structural level there is a general psychopathological factor (psychopathy or externalizing), non-emotional callousness and impulsivity from behavioral inhibition and activation systems, and negative affect traits as base structures. In the emotional level, the study found a risk component from emotional dysregulation and experiential avoidance. In the cognitive level, a key role of anger-rumination and violent ideation as explanatory variables of antisocial disorders. We concluded that the interaction of these identified variables makes it possible to generate an evidence-based transdiagnostic model.

An Examination of Psychomotor Disturbance in Current and Remitted MDD: An RDoC Study

Major depressive disorder (MDD) is a serious public health problem that has, at best, modest treatment response—potentially due to its heterogeneous clinical presentation. One way to parse the heterogeneity is to investigate the role of particular features of MDD, an endeavor that can also help identify novel and focal targets for treatment and prevention efforts. Our R01 focuses on the feature of psychomotor disturbance (e.g., psychomotor agitation (PmA) and retardation (PmR)), a particularly pernicious feature of MDD, that has not been examined extensively in MDD. Aim 1 is comparing three groups of individuals—those with current MDD (n = 100), remitted MDD (n = 100), and controls (n = 50)—on multiple measures of PmR and PmA (assessed both in the lab and in the subjects’ natural environment). Aim 2 is examining the structural (diffusion MRI) and functional (resting state fMRI) connectivity of motor circuitry of the three groups as well as the relation between motor circuitry and the proposed indicators of PmR and PmA. Aim 3 is following up with subjects three times over 18 months to evaluate whether motor symptoms change in tandem with overall depressive symptoms and functioning over time and/or whether baseline PmR/PmA predicts course of depression and functioning. Aim 3 is particularly clinically significant. Finding that motor functioning and overall depression severity co-vary over time, or that motor variables predict subsequent change in overall depression severity, would support the potential clinical utility of these novel, reliable, and easily administered motor assessments.

From bedside to bench and back: Translating ASD models

Autism spectrum disorders (ASD) represent a heterogeneous group of disorders defined by deficits in social interaction/communication and restricted interests, behaviors, or activities. Models of ASD, developed based on clinical data and observations, are used in basic science, the "bench," to better understand the pathophysiology of ASD and provide therapeutic options for patients in the clinic, the "bedside." Translational medicine creates a bridge between the bench and bedside that allows for clinical and basic science discoveries to challenge one another to improve the opportunities to bring novel therapies to patients. From the clinical side, biomarker work is expanding our understanding of possible mechanisms of ASD through measures of behavior, genetics, imaging modalities, and serum markers. These biomarkers could help to subclassify patients with ASD in order to better target treatments to a more homogeneous groups of patients most likely to respond to a candidate therapy. In turn, basic science has been responding to developments in clinical evaluation by improving bench models to mechanistically and phenotypically recapitulate the ASD phenotypes observed in clinic. While genetic models are identifying novel therapeutics targets at the bench, the clinical efforts are making progress by defining better outcome measures that are most representative of meaningful patient responses. In this review, we discuss some of these challenges in translational research in ASD and strategies for the bench and bedside to bridge the gap to achieve better benefits to patients.

Developing Dimensional, Pandiagnostic Inhibitory Control Constructs With Self-Report and Neuropsychological Data

Trait markers, or intermediate phenotypes linking different units of analysis (self-report, performance) from the Research Domain Criteria (RDoC) matrix across populations is a necessary step in identifying at-risk individuals. In the current study, 150 healthy controls (HC) and 456 individuals with bipolar disorder (BD) Type I or II, NOS (not otherwise specified) or Schizoaffective BD completed self-report neuropsychological tests of inhibitory control (IC) and executive functioning. Bifactor analyses were used to examine the factor structure of these measures and to evaluate for invariance across groups. Bifactor analyses found modest convergence of items from neuropsychological tests and self-report measures of IC among HC and BD. The factor scores showed evidence of a general IC construct (i.e., subdomain) across measures. Importantly, invariance testing indicated that the same construct was measured equally well across groups. Groups differed on the general factor for three of the four scales. Convergence on a general IC factor and invariance across diagnosis supports the use of combined dimensional measures to identify clinical risk and highlights how prospective RDoC studies might integrate units of analysis.

Distinct Associations Between Low Positive Affect, Panic, and Neural Responses to Reward and Threat During Late Stages of Affective Picture Processing

BACKGROUND

Abnormal patterns of attention to threat and reward have been proposed as potential mechanisms of dysfunction in anxiety and mood disorders. However, research on this topic has been inconsistent, perhaps because of both clinical heterogeneity in the samples assessed and measurement of attentional biases that is temporally imprecise.

METHODS

The present study measured transdiagnostic symptoms of anxiety and depression in 205 young adults and recorded affect-modulated event-related potentials in response to task-irrelevant pictures in a speeded response task.

RESULTS

Low positive affect was uniquely associated with reduced modulation of later event-related potentials (i.e., the P300 and the late positive potential) by rewarding images, suggesting deficits in sustained attention to reward. Low positive affect was also associated with a blunted threat-elicited late positive potential. Symptoms of panic were associated with an increased N1 to rewarding images, as well as an increased late positive potential to all picture types.

CONCLUSIONS

These data suggest that dysfunction in neural markers of sustained attention to threat and reward relate in specific ways to transdiagnostic symptom dimensions of anxiety and depression. Moreover, event-related potentials are likely to be useful in investigations of the time course of attentional abnormalities associated with these symptom dimensions.

Anxiety and Depression Symptom Dimensions Demonstrate Unique Relationships with the Startle Reflex in Anticipation of Unpredictable Threat in 8 to 14 Year-Old Girls

There is growing evidence that heightened sensitivity to unpredictability is a core mechanism of anxiety disorders. In adults, multiple anxiety disorders have been associated with a heightened startle reflex in anticipation of unpredictable threat. Child and adolescent anxiety has been linked to an increased startle reflex across baseline, safety, and threat conditions. However, it is unclear whether anxiety in youth is related to the startle reflex as a function of threat predictability. In a sample of 90 8 to 14 year-old girls, the present study examined the association between anxiety symptom dimensions and startle potentiation during a no, predictable, and unpredictable threat task. Depression symptom dimensions were also examined given their high comorbidity with anxiety and mixed relationship with the startle reflex and sensitivity to unpredictability. To assess current symptoms, participants completed the self-report Screen for Child Anxiety Related Emotional Disorders and Children's Depression Inventory. Results indicated that social phobia symptoms were associated with heightened startle potentiation in anticipation of unpredictable threat and attenuated startle potentiation in anticipation of predictable threat. Negative mood and negative self-esteem symptoms were associated with attenuated and heightened startle potentiation in anticipation of unpredictable threat, respectively. All results remained significant after controlling for the other symptom dimensions. The present study provides initial evidence that anxiety and depression symptom dimensions demonstrate unique associations with the startle reflex in anticipation of unpredictable threat in children and adolescents.

Behavioral observations of positive and negative valence systems in early childhood predict physiological measures of emotional processing three years later

BACKGROUND

The Research Domain Criteria (RDoC) constructs of Positive Valence Systems (PVS) and Negative Valence Systems (NVS) are presumed to manifest behaviorally through early-emerging temperamental negative affectivity (NA) and positive affectivity (PA). The late positive potential (LPP) is a physiological measure of attention towards both negative and positive emotional stimuli; however, its associations with behavioral aspects of PVS and NVS have yet to be examined.

METHODS

In a community sample of children (N = 340), we examined longitudinal relationships between observational measures of temperamental PA and NA assessed at age 6, and the LPP to both pleasant and unpleasant images assessed at age 9.

RESULTS

Lower PA at age 6 predicted reduced LPP amplitudes to pleasant, but not unpleasant, images. NA as a composite measure was not related to the LPP, but specific associations were observed with facets of NA: greater fear predicted an enhanced LPP to unpleasant images, whereas greater sadness predicted a reduced LPP to unpleasant images.

LIMITATIONS

We were unable to evaluate concurrent associations between behavioral observations of temperament and the LPP, and effect sizes were modest.

CONCLUSIONS

Results support correspondence between behavioral and physiological measures of emotional processing across development, and provide evidence of discriminant validity in that PA was specifically related to the LPP to pleasant images, while facets of NA were specifically linked to the LPP to unpleasant images. Distinct associations of temperamental sadness and fear with the LPP highlight the importance of further evaluating subconstructs of NVS.

Challenges of Fear Conditioning Research in the Age of RDoC

Abstract. As the criticism of the definition of the phenotype (i.e., clinical diagnosis) represents the major focus of the Research Domain Criteria (RDoC) initiative, it is somewhat surprising that discussions have not yet focused more on specific conceptual and procedural considerations of the suggested RDoC constructs, sub-constructs, and associated paradigms. We argue that we need more precise thinking as well as a conceptual and methodological discussion of RDoC domains and constructs, their interrelationships as well as their experimental operationalization and nomenclature. The present work is intended to start such a debate using fear conditioning as an example. Thereby, we aim to provide thought-provoking impulses on the role of fear conditioning in the age of RDoC as well as conceptual and methodological considerations and suggestions to guide RDoC-based fear conditioning research in the future.

Using a cultural and RDoC framework to conceptualize anxiety in Asian Americans

Asian Americans are one of the fastest growing minority groups in the United States; however, mental health within this population segment, particularly anxiety disorders, remains significantly understudied. Both the heterogeneity within the Asian American population and the multidimensional nature of anxiety contribute to difficulties in understanding anxiety in this population. The present paper reviewed two sources of heterogeneity within anxiety in Asian Americans: (1) cultural variables and (2) mechanisms or components of anxiety. Specifically, we examined four cultural variables most commonly found in research related to anxiety in Asian Americans: acculturation, loss of face, affect valuation, and individualism-collectivism. We also discussed ways to parse anxiety through a Research Domain Criteria (RDoC) framework, specifically focusing on sensitivity to acute and potential threat, constructs within the Negative Valence System. Previously unpublished preliminary data were presented to illustrate one way of examining ethnic differences in anxiety using an RDoC framework. Finally, this paper offered recommendations for future work in this area.

Understanding Suicide Risk within the Research Domain Criteria (RDoC) Framework: Insights, Challenges, and Future Research Considerations

Suicide is a leading cause of death worldwide. Prior research has focused primarily on sociodemographic and psychiatric risk factors with little improvement in the prediction or prevention of suicidal behavior over time. The Research Domain Criteria (RDoC) may be an especially useful framework for advancing research in this area. This paper provides a brief and broad overview of research on suicidal behavior relating to each of the RDoC domains-highlighting the RDoC construct(s) where research has focused, construct(s) where research is lacking, and suggestions for future research directions. We also discuss major challenges for suicide research within the RDoC framework, including the intersection of RDoC domains, interaction of domains with the environment, incorporation of developmental stage, integration of distal and proximal processes, and inclusion of suicide-specific constructs. We conclude by underscoring important considerations for future research aimed at using the RDoC framework to study suicidal behavior and other forms of psychopathology.

How many blinks are necessary for a reliable startle response? A test using the NPU-threat task

Emotion-modulated startle is a frequently used method in affective science. Although there is a growing literature on the reliability of this measure, it is presently unclear how many startle responses are necessary to obtain a reliable signal. The present study therefore evaluated the reliability of startle responding as a function of number of startle responses (NoS) during a widely used threat-of-shock paradigm, the NPU-threat task, in a clinical (N=205) and non-clinical (N=92) sample. In the clinical sample, internal consistency was also examined independently for healthy controls vs. those with panic disorder and/or major depression and retest reliability was assessed as a function of NoS. Although results varied somewhat by diagnosis and for retest reliability, the overall pattern of results suggested that six startle responses per condition were necessary to obtain acceptable reliability in clinical and non-clinical samples during this threat-of-shock paradigm in the present study.

Association between neural reactivity and startle reactivity to uncertain threat in two independent samples

Prior studies indicate that anxiety disorders are associated with heightened sensitivity to uncertain threat (U threat). Individual differences in reactivity to U threat have been measured in the laboratory with two methodologies-startle eyeblink potentiation and fMRI. While startle and fMRI are purported to relate to each other, very little research exists on whether individual differences in one measure are associated with individual differences in another and, thus, whether startle and fMRI capture shared mechanisms. Therefore, the current study was designed to investigate if and where in the brain measures of startle potentiation and fMRI BOLD signal correlate during response to U threat across two independent samples. Participants in both studies completed two threat anticipation tasks-once during collection of startle potentiation and once during fMRI. In Study 1 (n = 43), the startle and fMRI tasks both used electric shock as the threat. As an extension, in Study 2 (n = 38), the startle task used electric shock but the fMRI task used aversive images. Despite these methodological differences, greater startle potentiation to U threat was associated with greater dorsal anterior cingulate, caudate, and orbitofrontal cortex reactivity to U threat in both samples. The findings suggest that startle and fMRI measures of responding to U threat overlap, and points toward an integrated brain-behavior profile of aberrant U threat responding.

Impact of Panic on Psychophysiological and Neural Reactivity to Unpredictable Threat in Depression and Anxiety

Exaggerated anxious responding to unpredictable threat (U-threat) is a core feature of panic disorder (PD). However, it is unknown whether this abnormality is specific to the diagnosis of PD or would manifest along a continuum of panic symptomatology (PS). Additionally, little is known about the neural processes underlying this abnormality among those high in PS. Finally, no studies have tested whether startle potentiation and limbic neural reactivity - commonly used indices of U-threat responsivity - are associated and therefore reflect common abnormalities. These questions were investigated in 42 adults with a range of PS. U-threat responding was measured twice during threat-of-shock - once with startle and once with functional magnetic resonance imaging (fMRI). As hypothesized, PS positively predicted startle potentiation and dACC reactivity to U-threat. Startle potentiation and dACC activation to U-threat were positively associated. These results suggest a biobehavioral profile of aberrant responding to U-threat associated with PS.

Taking an RDoC lens to the study of panic disorder: A commentary on Hamm et al. and other thoughts on RDoC

The Research Domain Criteria (RDoC) initiative put forth by the National Institute of Mental Health represents an exciting new framework in which to study psychopathology. The article by Hamm et al. (2016) is an interesting application of an "RDoC lens" toward a program of research on panic disorder. This commentary highlights the many strengths of the Hamm et al. (2016) study-most notably the article's application of a well-studied animal model of anxiety (Fanselow's, , threat imminence model) to humans, utilization of an interesting behavioral paradigm (as an analog for avoidance behaviors in panic disorder), and using RDoC to examine predictors of treatment response. This commentary also discusses several questions about RDoC that arise out of Hamm et al. For example, (a) How should participants be selected for RDoC studies? (b) Are RDoC constructs risk factors (and risk factors for what)? (c) Besides Hamm et al.'s, approach, how else can RDoC be used in treatment studies? In sum, Hamm et al. is a very good example of an RDoC study, and in this early phase of the initiative, more examples for how the approach plays out are needed.

Blunted reward processing in remitted melancholic depression

Blunted reward response appears to be a trait-like marker of vulnerability for Major Depressive Disorder (MDD). As such, it should be present in remitted individuals; however, depression is a heterogeneous syndrome. Reward-related impairments may be more pronounced in individuals with melancholic depression. The present study examined neural responses to rewards in remitted melancholic depression (rMD; N = 29), remitted non-melancholic depression (rNMD; N = 56), and healthy controls (HC; N = 81). Event-related potentials to monetary gain and loss were recorded during a simple gambling paradigm. rMD was characterized by a blunted response to rewards relative to both the HC and the rNMD groups, who did not differ from one another. Moreover, the rMD and rNMD groups did not differ in course or severity of their past illnesses, or current depressive symptoms or functioning. Results suggest that blunted response to rewards may be a viable vulnerability marker for melancholic depression.

Conducting Psychopathology Prevention Research in the RDoC Era

The Research Domain Criteria (RDoC) initiative promoted by the National Institute of Mental Health emphasizes a dimensional approach to psychopathology that is agnostic to DSM diagnosis. The RDoC project offers exciting possibilities for advancing research aimed at preventing psychopathology. However, prevention has historically been defined using diagnostic status, requiring the field to redefine what constitutes prevention using an RDoC approach. This article outlines new criteria for prevention in the RDoC context and provides guidance for implementing these criteria. We also describe the role of prevention-mechanism trials that examine whether preventive interventions change proximal etiological mechanisms known to be associated with psychopathology. We hope that these modified criteria and recommendations will stimulate new possibilities for prevention research that will advance the field.

Clashing Diagnostic Approaches: DSM-ICD Versus RDoC

Since at least the middle of the past century, one overarching model of psychiatric classification has reigned supreme, namely, that of the Diagnostic and Statistical Manual of Mental Disorders and the International Statistical Classification of Diseases and Related Health Problems (herein referred to as DSM-ICD). This DSM-ICD approach embraces an Aristotelian view of mental disorders as largely discrete entities that are characterized by distinctive signs, symptoms, and natural histories. Over the past several years, however, a competing vision, namely, the Research Domain Criteria (RDoC) initiative launched by the National Institute of Mental Health, has emerged in response to accumulating anomalies within the DSM-ICD system. In contrast to DSM-ICD, RDoC embraces a Galilean view of psychopathology as the product of dysfunctions in neural circuitry. RDoC appears to be a valuable endeavor that holds out the long-term promise of an alternative system of mental illness classification. We delineate three sets of pressing challenges--conceptual, methodological, and logistical/pragmatic--that must be addressed for RDoC to realize its scientific potential. We conclude with a call for further research, including investigation of a rapprochement between Aristotelian and Galilean approaches to psychiatric classification.

Blunted neural response to errors as a trait marker of melancholic depression

Identification of biomarkers of vulnerability for Major Depressive Disorder is a high priority, but heterogeneity of the diagnosis can hinder research. Biomarkers of vulnerability should also be present in the absence of the diagnosis. The present study examined the magnitude of the error-related negativity (ERN), an event-related potential component following errors in a sample with remitted melancholic depression (N=17), remitted non-melancholic depression (N=33), and healthy controls (N=55). Remitted melancholic depression was uniquely characterized by a blunted ERN relative to the other two groups. Individuals with remitted non-melancholic depression did not differ from controls in the magnitude of the ERN. This was the case despite the fact that the melancholic and non-melancholic groups did not differ in course or severity of their past illnesses, or in their current functioning. Results suggest that the blunted ERN may be a viable vulnerability marker for melancholia.

Situating psychophysiological science within the Research Domain Criteria (RDoC) framework

The Research Domain Criteria (RDoC) reflects a paradigm shift in mental health research aimed at establishing a science of psychopathology that is grounded in neuroscience. In many ways, the RDoC approach to research has been utilized for decades by psychophysiologists who have leveraged a range of biological measures to study variability in psychological processes as a function of individual differences. We highlight the critical role of psychophysiology in the era of RDoC, and briefly review the 13 papers and commentary that form the current special issue.