Fear and safety learning in anxiety- and stress-related disorders: An updated meta-analysis

Fear learning processes are believed to play a crucial role in the development and maintenance of anxiety and stress-related disorders. To integrate results across different studies, we conducted a systematic meta-analysis following PRISMA guidelines to examine differences in fear conditioning during fear acquisition, extinction, and extinction recall between individuals with anxiety-related or stress-related disorders and healthy participants. This analysis updates the work of Duits et al. (2015) while also refining distinctions between physiological and behavioral outcomes and examining extinction recall. Our meta-analysis encompasses 77 studies published from 1986 to 2022, involving 2052 patients with anxiety disorders, obsessive-compulsive disorder, or post-traumatic stress disorder, and 3258 healthy controls. The results indicate significant differences in fear acquisition, extinction, and recall between the two groups. Specifically, during acquisition patients exhibited heightened physiological and behavioral responses to the CS- and reported increased affect ratings for the CS+ . During extinction and extinction recall, patients continue to show heightened threat expectancy and negative affect ratings towards the CS- and increased affect ratings towards the CS+ . No differences were found in CS+ /CS- differentiation between groups. These findings imply that individuals with anxiety and stress-related disorders may exhibit amplified responses to safety cues and stronger reactions to threat cues during fear conditioning, lasting through extinction and extinction recall. These changes may lead to increased sensitivity in detecting fear and slower extinction process, resulting in more enduring anxiety responses. We discuss these results in the context of existing literature on fear and safety learning and consider potential underlying mechanisms.

Preliminary Examination of Sympathetic Magic as a Psychological Endophenotype for Obsessive-Compulsive Disorder

Although sympathetic magic (SM) beliefs (i.e., irrational understanding of contagion transmission) are observed in obsessive-compulsive disorder (OCD), it is unclear if such beliefs are psychological endophenotypes. Furthermore, predictors of SM beliefs in OCD remain unknown. Accordingly, the present study examined whether SM beliefs function as an endophenotype for OCD and whether perceived vulnerability to disease (PVD) contributes to SM beliefs. A sample of 30 individuals with OCD, 26 first-degree relatives, and 25 age-matched healthy controls completed self-report questionnaires and a SM task where we touched a clean pencil to a "contaminated" toilet, and rated the degree to which the pencil was contaminated. A second pencil was touched to the first pencil and was then rated. This process was continued for 12 pencils (12 degrees of removal from contagion). Results revealed no significant differences in the extent to which the three groups perceived a "chain of contagion" (i.e., contamination slopes) for the successive degrees of removal from the original contagion. However, the OCD group reported significantly less contamination reduction on the task, a group difference that was mediated by PVD. These findings suggest that although SM beliefs may not be an OCD endophenotype, such beliefs may derive from a PVD.

The future of psychophysiology, then and now

Since its founding in 1973, Biological Psychology has showcased and provided invaluable support to psychophysiology, a field that has grown and changed enormously. This article discusses some constancies that have remained fundamental to the journal and to the field as well as some important trends. Some aspects of our science have not received due consideration, affecting not only the generalizability of our findings but the way we develop and evaluate our research questions and the potential of our field to contribute to the common good. The article offers a number of predictions and recommendations for the next period of growth of psychophysiology.

Evaluating the validity of animal models of mental disorder: from modeling syndromes to modeling endophenotypes

This paper provides a historical analysis of a shift in the way animal models of mental disorders were conceptualized: the shift from the mid-twentieth-century view, adopted by some, that animal models model syndromes classified in manuals such as the Diagnostic and Statistical Manual of Mental Disorders (DSM), to the later widespread view that animal models model component parts of psychiatric syndromes. I argue that in the middle of the twentieth century the attempt to maximize the face validity of animal models sometimes led to the pursuit of the ideal of an animal model that represented a behaviorally defined psychiatric syndrome as described in manuals such as the DSM. I show how developments within psychiatric genetics and related criticism of the DSM in the 1990s and 2000s led to the rejection of this ideal and how researchers in the first decade of the twenty-first century came to believe that animal models of mental disorders should model component parts of mental disorders, adopting a so-called endophenotype approach.

Aversiveness of errors and the error-related negativity (ERN): A systematic review on the affective states' manipulations findings

Error-related negativity (ERN) has been used to investigate neural mechanisms underlying error processing and conflict monitoring. Recent evidence highlights that affective and motivational states modulate the ERN and that aversiveness of errors plays a vital role in error monitoring. Therefore, our primary objective was to systematically evaluate and describe the influence of affect state-related manipulations on the ERN. A total of 51 publications identified from PsyInfo, PubMed, and PsyArticles databases were included following the Prisma procedures for systematic reviews. Papers were analyzed using sample attributes, psychological paradigms, and states manipulations. The present study shows that the ERN component has recurrently appeared to be sensitive to manipulations of affective states in the reviewed literature. However, conclusive findings concerning the affect state-dependent properties of the ERN remain elusive. Results are discussed considering heterogeneity in paradigms, variables, and the state-trait interactions. Furthermore, recommendations for future high-quality studies are provided along with the necessity of upcoming high-power replication attempts and more studies with positive affect manipulations.

Predictive utility of symptom measures in classifying anxiety and depression: A machine-learning approach

Major depressive disorder (MDD) and generalized anxiety disorder (GAD) are highly prevalent, co-occurring disorders with significant symptom overlap, posing challenges in accurately distinguishing and diagnosing these disorders. The tripartite model proposes that anxious arousal is specific to anxiety and anhedonia is specific to depression, though anxious apprehension may play a greater role in GAD than anxious arousal. The present study tested the efficacy of the Mood and Anxiety Symptom Questionnaire anhedonic depression (MASQ-AD) and anxious arousal (MASQ-AA) scales and the Penn State Worry Questionnaire (PSWQ) in identifying lifetime or current MDD, current major depressive episode (MDE), and GAD using binary support vector machine learning algorithms in an adult sample (n = 150). The PSWQ and MASQ-AD demonstrated predictive utility in screening for and identification of GAD and current MDE respectively, with the MASQ-AD eight-item subscale outperforming the MASQ-AD 14-item subscale. The MASQ-AA did not predict MDD, current MDE, or GAD, and the MASQ-AD did not predict current or lifetime MDD. The PSWQ and MASQ-AD are efficient and accurate screening tools for GAD and current MDE. Results support the tripartite model in that anhedonia is unique to depression, but inclusion of anxious apprehension as a separate dimension of anxiety is warranted.

Age-related changes and longitudinal stability of individual differences in ABCD Neurocognition measures

Temporal stability of individual differences is an important prerequisite for accurate tracking of prospective relationships between neurocognition and real-world behavioral outcomes such as substance abuse and psychopathology. Here we report age-related changes and longitudinal test-retest stability (TRS) for the Neurocognition battery of the Adolescent Brain and Cognitive Development (ABCD) study, which included the NIH Toolbox (TB) Cognitive Domain and additional memory and visuospatial processing tests administered at baseline (ages 9-11) and two-year follow-up. As expected, performance improved significantly with age, but the effect size varied broadly, with Pattern Comparison and the Crystallized Cognition Composite showing the largest age-related gain (Cohen's d:.99 and.97, respectively). TRS ranged from fair (Flanker test: r = 0.44) to excellent (Crystallized Cognition Composite: r = 0.82). A comparison of longitudinal changes and cross-sectional age-related differences within baseline and follow-up assessments suggested that, for some measures, longitudinal changes may be confounded by practice effects and differences in task stimuli or procedure between baseline and follow-up. In conclusion, a subset of measures showed good stability of individual differences despite significant age-related changes, warranting their use as prospective predictors. However, caution is needed in the interpretation of observed longitudinal changes as indicators of neurocognitive development.

ENIGMA-anxiety working group: Rationale for and organization of large-scale neuroimaging studies of anxiety disorders

Anxiety disorders are highly prevalent and disabling but seem particularly tractable to investigation with translational neuroscience methodologies. Neuroimaging has informed our understanding of the neurobiology of anxiety disorders, but research has been limited by small sample sizes and low statistical power, as well as heterogenous imaging methodology. The ENIGMA-Anxiety Working Group has brought together researchers from around the world, in a harmonized and coordinated effort to address these challenges and generate more robust and reproducible findings. This paper elaborates on the concepts and methods informing the work of the working group to date, and describes the initial approach of the four subgroups studying generalized anxiety disorder, panic disorder, social anxiety disorder, and specific phobia. At present, the ENIGMA-Anxiety database contains information about more than 100 unique samples, from 16 countries and 59 institutes. Future directions include examining additional imaging modalities, integrating imaging and genetic data, and collaborating with other ENIGMA working groups. The ENIGMA consortium creates synergy at the intersection of global mental health and clinical neuroscience, and the ENIGMA-Anxiety Working Group extends the promise of this approach to neuroimaging research on anxiety disorders.

Does crude measurement contribute to observed unidimensionality of psychological constructs? A demonstration with DSM-5 alcohol use disorder

Mental disorders are complex, multifaceted phenomena that are associated with profound heterogeneity and comorbidity. Despite the heterogeneity of mental disorders, most are generally considered unitary dimensions. We argue that certain measurement practices, especially using too few indicators per construct, preclude the detection of meaningful multidimensionality. We demonstrate the implications of crude measurement for detecting construct multidimensionality with alcohol use disorder (AUD). To do so, we used a large sample of college heavy drinkers (N = 909) for whom AUD symptomology was thoroughly assessed (87 items) and a blend of confirmatory factor analysis, exploratory factor analysis, and hierarchical clustering. A unidimensional AUD model with one item per symptom criterion fit the data well, whereas a unidimensional model with all items fit the data poorly. Starting with an 11-item AUD model, model fit decreased and the variability in factor loadings increased as additional items were added to the model. Additionally, multidimensional models outperformed unidimensional ones in terms of variance explained in theoretically relevant external criteria. All told, we converged on a hierarchically organized model of AUD with three broad, transcriterial dimensions that reflected tolerance, withdrawal, and loss of control. In addition to introducing a hierarchical model of AUD, we propose that thorough assessment of psychological constructs paired with serious consideration of alternative, multidimensional structures can move past the deadlock of their unidimensional representations. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

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.

Event-related potential (ERP) measures of error processing as biomarkers of externalizing disorders: A narrative review

Previous studies have shown that electrophysiological measures of error processing are affected in patients at risk or diagnosed with internalizing disorders, hence, suggesting that error processing could be a suitable biomarker for internalizing disorders. In this narrative review, we will evaluate studies that address the role of event-related potential (ERP) measures of error-processing in externalizing disorders and discuss to what extend these can be considered a biomarker for externalizing disorders. Currently, there is evidence for the notion that electrophysiological indices of error processing such as the error-related negativity (ERN) and error positivity (Pe) are reduced in individuals with substance use disorders, attention-deficit/hyperactivity disorder, and in forensic populations. However, it remains unclear whether this is also the case for other understudied disorders such as behavioral addiction. Furthermore, to fully understand how these deficits affect day to day behavior, we encourage research to focus on testing current theories and hypotheses of ERN and Pe. In addition, we argue that within an externalizing disorder, individual differences in error processing deficits may be related to prognosis and gender of the patient, methodological issues and presence of comorbidity. Next, we review studies that have related treatment trajectories with ERP measures of error processing, and we discuss the prospect of improving error processing as a treatment option. We conclude that ERP measures of error processing are candidate biomarkers for externalizing disorders, albeit we strongly urge researchers to continue looking into the predictive value of these measures in the etiology and treatment outcome through multi-method and longitudinal designs.

Evaluating endophenotypes for bipolar disorder

BACKGROUND

Phenotypic heterogeneity is a major impediment to the elucidation of the neurobiology and genetics of bipolar disorder. Endophenotype could help in reducing heterogeneity by defining biological traits that are more direct expressions of gene effects. The aim of this review is to examine the recent literature on clinical, epidemiological, neurobiological, and genetic findings and to select and evaluate candidate endophenotypes for bipolar disorder. Evaluating putative endophenotype could be helpful in better understanding the neurobiology of bipolar disorder by improving the definition of bipolar-related phenotypes in genetic studies. In this manner, research on endophenotypes could be useful to improve psychopathological diagnostics in the long-run by dissecting psychiatric macro phenotypes into biologically valid components.

MAIN BODY

The associations among the psychopathological and biological endophenotypes are discussed with respect to specificity, temporal stability, heritability, familiarity, and clinical and biological plausibility. Numerous findings regarding brain function, brain structure, neuropsychology and altered neurochemical pathways in patients with bipolar disorder and their relatives deserve further investigation. Overall, major findings suggest a developmental origin of this disorder as all the candidate endophenotypes that we have been able to select are present both in the early stages of the disorder as well as in subjects at risk.

CONCLUSIONS

Among the stronger candidate endophenotypes, we suggest circadian rhythm instability, dysmodulation of emotion and reward, altered neuroimmune state, attention and executive dysfunctions, anterior cingulate cortex thickness and early white matter abnormalities. In particular, early white matter abnormalities could be the result of a vulnerable brain on which new stressors are added in young adulthood which favours the onset of the disorder. Possible pathways that lead to a vulnerable brain are discussed starting from the data about molecular and imaging endophenotypes of bipolar disorder.

Frontal Beta Activity in the Meta-Intention of Children With Attention Deficit Hyperactivity Disorder

Children with attention deficit hyperactivity disorder (ADHD) have high theta and low beta activity in the frontal lobe. The higher the theta/beta ratio, the lower the level of central nervous system (CNS) cortical arousal. However, there is seldom evidence between electroencephalograms (EEGs) and the patient's intentionality to regulate the cortical activity of executive attention tasks. We investigated whether children with ADHD intended to improve their performance in executive attention tasks and whether that increased their brain activity. Fifty-one children with ADHD (ADHD) and 51 typical developing (TD) children were investigated using focused attention (FA) and search attention (SA) tasks and a simultaneous EEG. The children were then regrouped as faster (ADHD-F, TD-F) and slower (ADHD-S, TD-S) depending on reaction time (RT). Quantitative EEGs of frontal lobe theta and beta activity at frontal F3, F4, and Fz were used. Twenty-eight (54.9%) ADHD children were regrouped as ADHD-S and 14 (27.5%) as TD-S. The ADHD-S group, however, had poorer FA and SA performance than the other 3 groups did: fewer correct answers, more frequent impulsive and missing errors, and higher RT variations. There were no significant differences in theta activity, but the TD-S group had higher beta activity than the ADHD-S group did. We conclude that the ADHD-F and ADHD-S groups had different attention processes. beta activity did not increase in the ADHD-S group, and their executive attention performance in the FA and SA tests was poor. It seems ADHD-S had poor meta-intention function. The frontal beta activity might be a feasible training target of neurofeedback in ADHD-S patients.

Oscillatory connectivity as a mechanism of auditory sensory gating and its disruption in schizophrenia

Although innumerable studies using an auditory sensory gating paradigm have confirmed that individuals with schizophrenia (SZ) show less reduction in brain response to the second in a pair of clicks, this large literature has not yielded consensus on the circuit(s) responsible for gating nor for the gating difference in SZ. Clinically stable adult inpatients (N = 157) and matched community participants (N = 90) participated in a standard auditory sensory gating protocol. Responses to paired clicks were quantified as peak-to-peak amplitude from a response at approximately 50 ms to a response at approximately 100 ms in MEG-derived source waveforms. For bilateral sources in each of four regions near Heschl's gyrus, the gating ratio was computed as the response to the second stimulus divided by the response to the first stimulus. Spectrally resolved Granger causality quantified effective connectivity among regions manifested in alpha-band oscillatory coupling before and during stimulation. Poorer sensory gating localized to A1 in SZ than in controls confirmed previous results, here found in adjacent brain regions as well. Spontaneous, stimulus-independent effective connectivity within the hemisphere from angular gyrus to portions of the superior temporal gyrus was lower in SZ and correlated with gating ratio. Significant involvement of frontal and subcortical brain regions previously proposed as contributing to the auditory gating abnormality was not found. Findings point to endogenous connectivity evident in a sequence of activity from angular gyrus to portions of superior temporal gyrus as a mechanism contributing to normal and abnormal gating in SZ and potentially to sensory and cognitive symptoms.

Challenges and Strategies for Current Classifications of Depressive Disorders: Proposal for Future Diagnostic Standards

The Diagnostic and Statistical Manual of Mental Disorder, Fourth Edition (DSM-IV) was revised based on a combination of a categorical and a dimensional approach such that in the DSM, Fifth Edition (DSM-5), depressive disorders have been separated as a distinctive disease entity from bipolar disorders, consistent with the deconstruction of Kraepelinian dualism. Additionally, the diagnostic thresholds of depressive disorders may be reduced due to the addition of "hopelessness" to the subjective descriptors of depressed mood and the removal of the "bereavement exclusion." Manic/hypomanic, psychotic, and anxious symptoms in major depressive disorder (MDD) and other depressive disorders are described using the transdiagnostic specifiers of "with mixed features," "with psychotic features," and "with anxious distress," respectively. Additionally, due to the polythetic and operational characteristics of the DSM-5 diagnostic criteria, the heterogeneity of MDD is inevitable. Thus, 227 different symptom combinations fulfill the DSM-5 diagnostic criteria for MDD. This heterogeneity of MDD is criticized in view of the Wittgensteinian analogy of language game. Depression subtypes determined by disturbances in monoamine levels and the severity of the disease have been identified in the literature. According to a review of the Gottesman and Gould criteria, neuroticism, morning cortisol, cortisol awakening response, asymmetry in frontal cortical activity on electroencephalography (EEG), and probabilistic reward learning, among other variables, are evidenced as endophenotypes for depressive disorders. Network analysis has been proposed as a potential method to compliment the limitations of current diagnostic criteria and to explore the pathways between depressive symptoms, as well as to identify novel and interesting relationships between depressive symptoms. Based on the literature on network analysis in this field, no differences in the centrality index of the DSM and non-DSM symptoms were repeatedly present among patients with MDD. Furthermore, MDD and other depressive syndromes include two of the Research Domain Criteria (RDoC), including the Loss construct within the Negative Valence Systems domains and various Reward constructs within the Positive Valence Systems domain.

Envelope Following Response to 440 Hz Carrier Chirp-Modulated Tones Show Clinically Relevant Changes in Schizophrenia

The 40 Hz auditory steady-state response (ASSR) impairment is suggested as an electrophysiological biomarker of schizophrenia; however, existing data also points to the deficiency of low and high frequency ASSR responses. In order to obtain the full picture of potential impairment in schizophrenia, it is important to test responses at different frequencies. The current study aims to evaluate a wide frequency range (1-120 Hz) in response to brief low-frequency carrier chirp-modulated tones in a group of patients with schizophrenia. The EEG-derived envelope following responses (EFRs) were obtained in a group of male patients with schizophrenia (N = 18) and matched controls (N = 18). While subjects were watching silent movies, 440 Hz carrier chirp-modulated at 1-120 Hz tones were presented. Phase-locking index and evoked amplitude in response to stimulation were assessed and compared on point-to-point basis. The peak frequency of the low gamma response was estimated. Measures were correlated with psychopathology-positive, negative, total scores of the Positive and Negative Syndrome Scale (PANSS), and hallucination subscale scores. In comparison to controls, patients showed (1) reduced power of theta-beta (4-18 Hz) responses, (2) intact but slower low gamma (30-60 Hz), and (3) reduced high gamma (95-120 Hz) responses. No correlation survived the Bonferroni correction, but a sign of positive association between low gamma phase-locking and the prevalence of hallucinations, and a sign of negative association between high gamma phase-locking and the total PANSS scores were observed. Brain networks showed impaired capabilities to generate EFRs at different frequencies in schizophrenia; moreover, even when responses of patients did not significantly differ from controls on the group level, they still showed potentially clinically relevant variability.

Reintroducing Consciousness in Psychopathology: Review of the Literature and Conceptual Framework

Alterations in consciousness are among the most common transdiagnostic psychopathological symptoms. Therefore clinical practice would benefit from a clear conceptual framework that guides the recognition, comprehension, and treatment of consciousness disorders. However, contemporary psychopathology lacks such a framework. We describe how pathology of consciousness is currently being addressed in clinical psychology and psychiatry so far, and how the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and International Classification of Diseases, Tenth Edition (ICD-10) refer to this subject. A brief review of the literature on consciousness is then given. After describing psychological perspectives on consciousness and discussing theoretical issues involved in exploring consciousness, we offer a practical clinical working definition of consciousness and we illustrate its connections with a variety of diagnoses. Making use of Jean-Paul Sartre’s distinctions among: states, functions, qualities, and structure, provide a conceptual framework to understand consciousness, to refine diagnostics and to guide the development of therapeutic possibilities in clinical practice.

Investigating microstructure of white matter tracts as candidate endophenotypes of Social Anxiety Disorder - Findings from the Leiden Family Lab study on Social Anxiety Disorder (LFLSAD)

BACKGROUND

Social anxiety disorder (SAD) is a mental illness with a complex, partially genetic background. Differences in characteristics of white matter (WM) microstructure have been reported in patients with SAD compared to healthy controls. Also, WM characteristics are moderately to highly heritable. Endophenotypes are measurable characteristics on the road from genotype to phenotype, putatively reflective of genetically based disease mechanisms. In search of candidate endophenotypes of SAD we used a unique sample of SAD patients and their family members of two generations to explore microstructure of WM tracts as candidate endophenotypes. We focused on two endophenotype criteria: co-segregation with social anxiety within the families, and heritability.

METHODS

Participants (n = 94 from 8 families genetically vulnerable for SAD) took part in the Leiden Family Lab Study on Social Anxiety Disorder (LFLSAD). We employed tract-based spatial statistics to examine structural WM characteristics, being fractional anisotropy (FA), axial diffusivity (AD), mean diffusivity (MD) and radial diffusivity (RD), in three a-priori defined tracts of interest: uncinate fasciculus (UF), superior longitudinal fasciculus (SLF) and inferior longitudinal fasciculus (ILF). Associations with social anxiety symptoms and heritability were estimated.

RESULTS

Increased FA in the left and right SLF co-segregated with symptoms of social anxiety. These findings were coupled with decreased RD and MD. All characteristics of WM microstructure were estimated to be at least moderately heritable.

CONCLUSION

These findings suggest that alterations in WM microstructure in the SLF could be candidate endophenotypes of SAD, as they co-segregated within families genetically vulnerable for SAD and are heritable. These findings further elucidate the genetic susceptibility to SAD and improve our understanding of the overall etiology.

Heritability of overlapping impulsivity and compulsivity dimensional phenotypes

Impulsivity and compulsivity are traits relevant to a range of mental health problems and have traditionally been conceptualised as distinct constructs. Here, we reconceptualised impulsivity and compulsivity as partially overlapping phenotypes using a bifactor modelling approach and estimated heritability for their shared and unique phenotypic variance within a classical twin design. Adult twin pairs (N = 173) completed self-report questionnaires measuring psychological processes related to impulsivity and compulsivity. We fitted variance components models to three uncorrelated phenotypic dimensions: a general impulsive-compulsive dimension; and two narrower phenotypes related to impulsivity and obsessiveness.There was evidence of moderate heritability for impulsivity (A² = 0.33), modest additive genetic or common environmental effects for obsessiveness (A² = 0.25; C² = 0.23), and moderate effects of common environment (C² = 0.36) for the general dimension, This general impulsive-compulsive phenotype may reflect a quantitative liability to related mental health disorders that indexes exposure to potentially modifiable environmental risk factors.

The Utility of Event-Related Potentials in Clinical Psychology

Event-related potentials (ERPs) are direct measures of brain activity that can be leveraged for clinically meaningful research. They can relate robustly both to continuous measures of individual difference and to categorical diagnoses in ways that clarify similarities and distinctions between apparently related disorders and traits. ERPs can be linked to genetic risk, can act as moderators of developmental trajectories and responses to stress, and can be leveraged to identify those at greater risk for psychopathology, especially when used in combination with other neural and self-report measures. ERPs can inform models of the development of, and risk for, psychopathology. Finally, ERPs can be used as targets for existing and novel interventions and prevention efforts. We provide concrete examples for each of these possibilities by focusing on programmatic research on the error-related negativity and anxiety, and thus show that ERPs are poised to make greater contributions toward the identification, prediction, treatment, and prevention of mental disorders.

The erring brain: Error-related negativity as an endophenotype for OCD-A review and meta-analysis

Obsessive-compulsive disorder (OCD) is a complex and heterogeneous disorder that is associated with high personal and societal costs. Feelings of doubt, worry, and repetitive behavior, key symptoms of OCD, have been linked to hyperactive error signals in the brain. The error-related negativity (ERN) represents a validated marker of error processing in the ERP. Increased ERN amplitudes in OCD have been reported very robustly over the last 20 years. This article integrates results from 38 studies analyzing the ERN in OCD, using a quantitative meta-analysis. Meta-regressions were used to examine potential moderators such as task type, symptom severity, age, and sample size. The meta-analysis reveals a robust increase of ERN in OCD patients compared to healthy participants in response-conflict tasks (SMD -0.55) that is not modulated by symptom severity and age. No increase in ERN in OCD was observed in tasks that do not induce response conflict (SMD -0.10). In addition to the meta-analysis, the current article reviews evidence supporting that increased ERN amplitudes in OCD fulfill central criteria for an endophenotype. Further, the specificity of increased ERN amplitudes for OCD and its suitability as a potential transdiagnostic endophenotype is discussed. Finally, the clinical utility and clinical applications are examined. Overall, the evidence that increased ERN amplitudes represent a promising endophenotype indicating vulnerability for OCD is compelling. Furthermore, alterations in ERN are not limited to OCD and may constitute a transdiagnostic endophenotype. Altered neural error signals might serve as a diagnostic or predictive marker and represent a promising target for interventions.

Magnetoencephalography for Schizophrenia

Schizophrenia (Sz) is a chronic mental disorder characterized by disturbances in thought (such as delusions and confused thinking), perception (hearing voices), and behavior (lack of motivation). The lifetime prevalence of Sz is between 0.3% and 0.7%, with late adolescence and early adulthood, the peak period for the onset of psychotic symptoms. Causal factors in Sz include environmental and genetic factors and especially their interaction. About 50% of individuals with a diagnosis of Sz have lifelong impairment.

Imaging the socially-anxious brain: recent advances and future prospects

Social anxiety disorder (SAD) is serious psychiatric condition with a genetic background. Insight into the neurobiological alterations underlying the disorder is essential to develop effective interventions that could relieve SAD-related suffering. In this expert review, we consider recent neuroimaging work on SAD. First, we focus on new results from magnetic resonance imaging studies dedicated to outlining biomarkers of SAD, including encouraging findings with respect to structural and functional brain alterations associated with the disorder. Furthermore, we highlight innovative studies in the field of neuroprediction and studies that established the effects of treatment on brain characteristics. Next, we describe novel work aimed to delineate endophenotypes of SAD, providing insight into the genetic susceptibility to develop the disorder. Finally, we outline outstanding questions and point out directions for future research.

Linking genes, circuits, and behavior: network connectivity as a novel endophenotype of externalizing

BACKGROUND

Externalizing disorders are known to be partly heritable, but the biological pathways linking genetic risk to the manifestation of these costly behaviors remain under investigation. This study sought to identify neural phenotypes associated with genomic vulnerability for externalizing disorders.

METHODS

One-hundred fifty-five White, non-Hispanic veterans were genotyped using a genome-wide array and underwent resting-state functional magnetic resonance imaging. Genetic susceptibility was assessed using an independently developed polygenic score (PS) for externalizing, and functional neural networks were identified using graph theory based network analysis. Tasks of inhibitory control and psychiatric diagnosis (alcohol/substance use disorders) were used to measure externalizing phenotypes.

RESULTS

A polygenic externalizing disorder score (PS) predicted connectivity in a brain circuit (10 nodes, nine links) centered on left amygdala that included several cortical [bilateral inferior frontal gyrus (IFG) pars triangularis, left rostral anterior cingulate cortex (rACC)] and subcortical (bilateral amygdala, hippocampus, and striatum) regions. Directional analyses revealed that bilateral amygdala influenced left prefrontal cortex (IFG) in participants scoring higher on the externalizing PS, whereas the opposite direction of influence was observed for those scoring lower on the PS. Polygenic variation was also associated with higher Participation Coefficient for bilateral amygdala and left rACC, suggesting that genes related to externalizing modulated the extent to which these nodes functioned as communication hubs.

CONCLUSIONS

Findings suggest that externalizing polygenic risk is associated with disrupted connectivity in a neural network implicated in emotion regulation, impulse control, and reinforcement learning. Results provide evidence that this network represents a genetically associated neurobiological vulnerability for externalizing disorders.

Target-related parietal P3 and medial frontal theta index the genetic risk for problematic substance use

Theoretical and empirical work suggests that problematic substance use (PSU) is associated with individual differences in prefrontal cortex activity. While research has strongly linked parietal P3 amplitude reduction (P3AR) to genetic risk for problematic substance use, few studies have tested whether prefrontal EEG measures are sensitive to this genetic liability. In addition to P3, oddball target detection tasks elicit medial frontal theta power, reflecting attentional allocation, and parietal delta, indexing decision making or stimulus-response link updating. Midfrontal theta and parietal delta may index neurocognitive processes relevant to PSU beyond P3AR. The present investigation examined the etiological relationship between PSU and P3, frontal theta, and parietal delta in a large twin sample (N = 754). EEG was recorded during a visual oddball task. Greater PSU was associated with reduced target P3 amplitude and midfrontal theta/parietal delta power, and increased mean reaction time and reaction time variability (RTV; indexing attentional fluctuations). P3, theta, and RTV, but not delta or mean RT, explained unique variance in PSU (R2  = 0.04). Twin biometric modeling indicated a genetic relationship between PSU and P3, theta, and RTV. Theta accounted for distinct genetic variance in PSU beyond P3 and RTV. Together, 23% of the total additive genetic variance in PSU was explained by the three endophenotypes. Results replicate P3AR as an endophenotype and provide support for additional behavioral (RTV) and neurophysiological (midfrontal theta) endophenotypes of PSU. Reduced theta and greater RTV may reflect variations in a prefrontal attentional network that confers genetic risk for substance use problems.

How to determine whether conceptual endophenotypes can improve clinical outcomes in patients suffering from major depression: An exploratory approach

Depression is a complex mental health disorder, resulting in a high degree of disability. Since symptom constellation, course, and outcome are heterogeneous in these patients, current research initiatives are striving to establish stratified diagnostic and treatment approaches. In the past two decades, Dirk Hellhammer and his team introduced Neuropattern, a new diagnostic concept, which is based on conceptual endophenotypes of the stress response network. We explore how to use this concept in clinical practice in order to ultimately determine whether it brings any value over standard care. In view of the novelty of the concept and the difficulties dealing with such a concept at a practical level, it was necessary to initiate an exploratory study to determine key factors for planning future clinical trials. We report results and knowledge gained from an exploratory single-site study investigating the use and potential benefits of Neuropattern in standard care. Inpatients (ICD-10 diagnosis F32, F33; Nö=ö178) were allocated to either treatment as usual (standard group, SG) or a novel Neuropattern oriented exploratory treatment (intervention group, IG). Symptom severity was assessed with psychometric tests at admission to hospital, during the first six weeks, and upon discharge from the hospital. In addition, direct and indirect costs were assessed for the 3-month-intervals prior to and after the hospital stay. Compared to the SG, depression scores of patients in the IG showed a faster decline once psychotherapeutic and pharmacological treatment were based on an individualized explanatory model. The patients in the IG with an F33 diagnosis showed a more pronounced reduction of depression severity during the stay in the hospital and a stronger and quicker reduction of general symptom severity. Comparing the average depression scores at the start of the study and after six weeks, symptom severity was reduced in all Neuropattern groups. Some limitations of the study have to be mentioned: The study was not blinded, was single-site, included highly depressed inpatients only, and was conducted for no longer than 8 months. The results highlight some important issues regarding taking the Neuropattern approach to the bedside and researching its efficacy and effectiveness to support personalized treatments in clinical care.

Associations and Heritability of Auditory Encoding, Gray Matter, and Attention in Schizophrenia

BACKGROUND

Auditory encoding abnormalities, gray-matter loss, and cognitive deficits are all candidate schizophrenia (SZ) endophenotypes. This study evaluated associations between and heritability of auditory network attributes (function and structure) and attention in healthy controls (HC), SZ patients, and unaffected relatives (UR).

METHODS

Whole-brain maps of M100 auditory activity from magnetoencephalography recordings, cortical thickness (CT), and a measure of attention were obtained from 70 HC, 69 SZ patients, and 35 UR. Heritability estimates (h2r) were obtained for M100, CT at each group-difference region, and the attention measure.

RESULTS

SZ patients had weaker bilateral superior temporal gyrus (STG) M100 responses than HC and a weaker right frontal M100 response than UR. Abnormally large M100 responses in left superior frontal gyrus were observed in UR and SZ patients. SZ patients showed smaller CT in bilateral STG and right frontal regions. Interrelatedness between 3 putative SZ endophenotypes was demonstrated, although in the left STG the M100 and CT function-structure associations observed in HC and UR were absent in SZ patients. Heritability analyses also showed that right frontal M100 and bilateral STG CT measures are significantly heritable.

CONCLUSIONS

Present findings indicated that the 3 SZ endophenotypes examined are not isolated markers of pathology but instead are connected. The pattern of auditory encoding group differences and the pattern of brain function-structure associations differ as a function of brain region, indicating the need for regional specificity when studying these endophenotypes, and with the presence of left STG function-structure associations in HC and UR but not in SZ perhaps reflecting disease-associated damage to gray matter that disrupts function-structure relationships in SZ.

Deriving alternative criteria sets for alcohol use disorders using statistical optimization: Results from the National Survey on Drug Use and Health

Much of the foundation of clinical practice, psychiatric epidemiology, and research into the etiology, course, prevention, and treatment of alcohol use disorder (AUD) rests on psychiatric diagnosis. However, existing research has failed to adequately exploit empirical techniques and existing databases to derive criteria considered optimal with respect to predicting external correlates. The current project adopts a novel approach to deriving new diagnostic criteria sets and rules for AUD. Utilizing the 2010 (N = 24,120) and 2013 (N = 23,627) National Survey on Drug Use and Health (NSDUH; Substance Abuse and Mental Health Services Administration [SAMHSA], 2011, 2014) data sets, we performed a statistical optimization procedure, using complete enumeration, on participants 21 or older who had consumed at least 1 alcoholic beverage in the past year. The goal was to maximize the distance (based on Cohen's d) between mean levels of the optimization criteria (i.e., consumption and functional impairment) in those with an AUD diagnosis versus those without. In contrast with current convention, AUD is derived transparently using a data-driven approach. The best solution included 9 criteria with a diagnostic threshold of 3, while the second-best solution comprised 5 criteria with a threshold of 2. External validation demonstrated both solutions perform similarly, suggesting it is appropriate to use either, depending on the goal of the diagnosis. Overall, statistical optimization approaches can yield highly efficient criteria sets and rules, although multiple, near equivalently performing solutions can be generated. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

A Working Hypothesis for the Role of the Cerebellum in Impulsivity and Compulsivity

Growing evidence associates cerebellar abnormalities with several neuropsychiatric disorders in which compulsive symptomatology and impulsivity are part of the disease pattern. Symptomatology of autism, addiction, obsessive-compulsive (OCD), and attention deficit/hyperactivity (ADHD) disorders transcends the sphere of motor dysfunction and essentially entails integrative processes under control of prefrontal-thalamic-cerebellar loops. Patients with brain lesions affecting the cortico-striatum thalamic circuitry and the cerebellum indeed exhibit compulsive symptoms. Specifically, lesions of the posterior cerebellar vermis cause affective dysregulation and deficits in executive function. These deficits may be due to impairment of one of the main functions of the cerebellum, implementation of forward internal models of the environment. Actions that are independent of internal models may not be guided by predictive relationships or a mental representation of the goal. In this review article, we explain how this deficit might affect executive functions. Additionally, regionalized cerebellar lesions have been demonstrated to impair other brain functions such as the emergence of habits and behavioral inhibition, which are also altered in compulsive disorders. Similar to the infralimbic cortex, clinical studies and research in animal models suggest that the cerebellum is not required for learning goal-directed behaviors, but it is critical for habit formation. Despite this accumulating data, the role of the cerebellum in compulsive symptomatology and impulsivity is still a matter of discussion. Overall, findings point to a modulatory function of the cerebellum in terminating or initiating actions through regulation of the prefrontal cortices. Specifically, the cerebellum may be crucial for restraining ongoing actions when environmental conditions change by adjusting prefrontal activity in response to the new external and internal stimuli, thereby promoting flexible behavioral control. We elaborate on this explanatory framework and propose a working hypothesis for the involvement of the cerebellum in compulsive and impulsive endophenotypes.

Error-related brain activity as a transdiagnostic endophenotype for obsessive-compulsive disorder, anxiety and substance use disorder

BACKGROUND

Increased neural error-signals have been observed in obsessive-compulsive disorder (OCD), anxiety disorders, and inconsistently in depression. Reduced neural error-signals have been observed in substance use disorders (SUD). Thus, alterations in error-monitoring are proposed as a transdiagnostic endophenotype. To strengthen this notion, data from unaffected individuals with a family history for the respective disorders are needed.

METHODS

The error-related negativity (ERN) as a neural indicator of error-monitoring was measured during a flanker task from 117 OCD patients, 50 unaffected first-degree relatives of OCD patients, and 130 healthy comparison participants. Family history information indicated, that 76 healthy controls were free of a family history for psychopathology, whereas the remaining had first-degree relatives with depression (n = 28), anxiety (n = 27), and/or SUD (n = 27).

RESULTS

Increased ERN amplitudes were found in OCD patients and unaffected first-degree relatives of OCD patients. In addition, unaffected first-degree relatives of individuals with anxiety disorders were also characterized by increased ERN amplitudes, whereas relatives of individuals with SUD showed reduced amplitudes.

CONCLUSIONS

Alterations in neural error-signals in unaffected first-degree relatives with a family history of OCD, anxiety, or SUD support the utility of the ERN as a transdiagnostic endophenotype. Reduced neural error-signals may indicate vulnerability for under-controlled behavior and risk for substance use, whereas a harm- or error-avoidant response style and vulnerability for OCD and anxiety appears to be associated with increased ERN. This adds to findings suggesting a common neurobiological substrate across psychiatric disorders involving the anterior cingulate cortex and deficits in cognitive control.

Dimensional thinking in psychiatry in the era of the Research Domain Criteria (RDoC)

The biological mechanisms underlying psychiatric diagnoses are not well defined. Clinical diagnosis based on categorical systems exhibit high levels of heterogeneity and co-morbidity. The Research Domain Criteria (RDoC) attempts to reconceptualize psychiatric disorders into transdiagnostic functional dimensional constructs based on neurobiological measures and observable behaviour. By understanding the underlying neurobiology and pathophysiology of the relevant processes, the RDoC aims to advance biomarker development for disease prediction and treatment response. This important evolving dimensional framework must also consider environmental factors. Emerging evidence suggests that gut microbes (microbiome) play a physiological role in brain diseases by modulating neuroimmune, neuroendocrine and neural signalling pathways between the gut and the brain. The integration of the gut microbiome signature as an additional dimensional component of the RDoC may enhance precision psychiatry.

Altered Neurobiological Processing of Unintentional Social Norm Violations: A Multiplex, Multigenerational Functional Magnetic Resonance Imaging Study on Social Anxiety Endophenotypes

BACKGROUND

Patients with social anxiety disorder (SAD) fear negative evaluation in social situations. Specifically, previous work indicated that social anxiety is associated with increased medial prefrontal cortex activation in response to unintentional social norm (SN) transgressions, accompanied by increased embarrassment ratings for such SN violations. Here, we used data from the multiplex, multigenerational LFLSAD (Leiden Family Lab study on Social Anxiety Disorder), which involved two generations of families genetically enriched for SAD, and investigated whether these neurobiological and behavioral correlates of unintentional SN processing are SAD endophenotypes. Of four endophenotype criteria, we examined two: first, the cosegregation of these characteristics with social anxiety (SA) within families of SAD probands (criterion 4), and second, the heritability of the candidate endophenotypes (criterion 3).

METHODS

Participants (n = 110, age range 9.0-61.5 years, eight families) performed the revised Social Norm Processing Task; functional magnetic resonance imaging data and behavioral ratings related to this paradigm were used to examine whether brain activation in response to processing unintentional SN violations and ratings of embarrassment were associated with SA levels. Next, heritability of these measurements was estimated.

RESULTS

As expected, voxelwise functional magnetic resonance imaging analyses revealed positive associations between SA levels and brain activation in the medial prefrontal cortex and medial temporal gyrus, superior temporal gyrus, and superior temporal sulcus, and these brain activation levels displayed moderate to moderately high heritability. Furthermore, although SA levels correlated positively with behavioral ratings of embarrassment for SN transgressions, these behavioral characteristics were not heritable.

CONCLUSIONS

These results show, for the first time, that brain responses in the medial prefrontal cortex and medial temporal gyrus, superior temporal gyrus, and superior temporal sulcus, related to processing unintentional SN violations, provide a neurobiological candidate endophenotype of SAD.

Thrombin and the Coag-Inflammatory Nexus in Neurotrauma, ALS, and Other Neurodegenerative Disorders

This review details our current understanding of thrombin signaling in neurodegeneration, with a focus on amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease) as well as future directions to be pursued. The key factors are multifunctional and involved in regulatory pathways, namely innate immune and the coagulation cascade activation, that are essential for normal nervous system function and health. These two major host defense systems have a long history in evolution and include elements and regulators of the coagulation pathway that have significant impacts on both the peripheral and central nervous system in health and disease. The clotting cascade responds to a variety of insults to the CNS including injury and infection. The blood brain barrier is affected by these responses and its compromise also contributes to these detrimental effects. Important molecules in signaling that contribute to or protect against neurodegeneration include thrombin, thrombomodulin (TM), protease activated receptor 1 (PAR1), damage associated molecular patterns (DAMPs), such as high mobility group box protein 1 (HMGB1) and those released from mitochondria (mtDAMPs). Each of these molecules are entangled in choices dependent upon specific signaling pathways in play. For example, the particular cleavage of PAR1 by thrombin vs. activated protein C (APC) will have downstream effects through coupled factors to result in toxicity or neuroprotection. Furthermore, numerous interactions influence these choices such as the interplay between HMGB1, thrombin, and TM. Our hope is that improved understanding of the ways that components of the coagulation cascade affect innate immune inflammatory responses and influence the course of neurodegeneration, especially after injury, will lead to effective therapeutic approaches for ALS, traumatic brain injury, and other neurodegenerative disorders.

Oscillatory brain dynamics supporting impaired Stroop task performance in schizophrenia-spectrum disorder

The Stroop color-word interference task, prompting slower response to color-incongruent than to congruent items, is often used to study neural mechanisms of inhibitory control and dysfunction in schizophrenia-spectrum disorders. Inconsistent findings of an augmented Stroop effect limit identification of relevant dysfunctional mechanism(s) in schizophrenia. The present study sought to advance understanding of normal and impaired neural oscillatory dynamics by distinguishing interference detection and response preparation during the Stroop task in schizophrenia-spectrum disorders via analysis of behavioral performance and 4-7 Hz (theta) and 10-30 Hz (alpha/beta) EEG oscillations in 40 patients (SZ) and 27 healthy comparison participants (HC). SZ responded more slowly and showed less dorsal anterior cingulate (dACC) theta enhancement during INC trials, less enhancement of dACC-sensorimotor cortex connectivity (theta phase synchrony) during INC trials, more alpha/beta suppression though less enhancement of that suppression during INC trials, and slower post-response alpha/beta rebound than did HC. Reaction time distributions showed larger group and Stroop effects during the 25% of trials with the slowest responses. Poorer theta phase coherence in patients indicates impaired communication between regions associated with interference processing (dACC) and response preparation (sensorimotor cortex). Results suggest a failure cascade in which compromised behavioral Stroop effects are driven at least in part by dysfunctional interference processing (less theta power increase) prompting dysfunctional motor response preparation (less alpha/beta power suppression). Inconsistent Stroop effects in past studies of schizophrenia may result from differing task parameters sampling different degrees of Stroop task difficulty.

Mismatch negativity and cognitive performance in the course of schizophrenia

BACKGROUND

Cognitive deficits and abnormal event-related brain potentials (ERP) have been proposed as risk markers for the development of schizophrenia. Evidence is inconclusive whether these markers indicate a risk for the development of psychosis or illness progression.

METHODS

The present study aimed at further clarification by comparing symptom expression (Brief Psychiatric Rating Scale, BRPS), the ERP Mismatch Negativity (MMN), and neuropsychological performance on the MATRICS Consensus Cognitive Battery between healthy controls (HC, n = 38) and individuals at different stages of illness: individuals at risk for psychosis (ARP, n = 33), patients at first admission, thus, early stage (ES, n = 35), chronic schizophrenia patients (CS, n = 25). Moreover, symptom expression was reassessed for ARP and ES at a 6 months follow-up.

RESULTS

MMN was smaller in individuals with manifest psychosis (ES, CS) than in HC, but did not differ between ARP and HC. In contrast, ARP showed similar cognitive deficits as ES and CS, all three groups differing from HC. Lower cognitive performance predicted higher symptom severity at index assessments and 6 months follow-up in ARP and ES, while MMN did not explain additional variance.

CONCLUSION

MMN seems to mark manifest psychosis, independent of early or chronic stage, while cognitive deficits mark early present psychopathology in individuals at risk for and with diagnosed psychosis rather than illness progression.

Abnormal temporal lobe morphology in asymptomatic relatives of patients with hippocampal sclerosis: A replication study

We investigated gray and white matter morphology in patients with mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE+HS) and first-degree asymptomatic relatives of patients with mTLE+HS. Using T1-weighted magnetic resonance imaging (MRI), we sought to replicate previously reported findings of structural surface abnormalities of the anterior temporal lobe in asymptomatic relatives of patients with mTLE+HS in an independent cohort. We performed whole-brain MRI in 19 patients with mTLE+HS, 14 first-degree asymptomatic relatives of mTLE+HS patients, and 32 healthy control participants. Structural alterations in patients and relatives compared to controls were assessed using automated hippocampal volumetry and cortical surface-based morphometry. We replicated previously reported cortical surface area contractions in the ipsilateral anterior temporal lobe in both patients and relatives compared to healthy controls, with asymptomatic relatives showing similar but less extensive changes than patients. These findings suggest morphologic abnormality in asymptomatic relatives of mTLE+HS patients, suggesting an inherited brain structure endophenotype.

Dopamine and Working Memory: Genetic Variation, Stress and Implications for Mental Health

At the molecular level, the neurotransmitter dopamine (DA) is a key regulatory component of executive function in the prefrontal cortex (PFC) and dysfunction in dopaminergic (DAergic) circuitry has been shown to result in impaired working memory (WM). Research has identified multiple common genetic variants suggested to impact on the DA system functionally and also behaviourally to alter WM task performance. In addition, environmental stressors impact on DAergic tone, and this may be one mechanism by which stressors confer vulnerability to the development of neuropsychiatric conditions. This chapter aims to evaluate the impact of key DAergic gene variants suggested to impact on both synaptic DA levels (COMT, DAT1, DBH, MAOA) and DA receptor function (ANKK1, DRD2, DRD4) in terms of their influence on visuospatial WM. The role of stressors and interaction with the genetic background is discussed in addition to discussion around some of the implications for precision psychiatry. This and future work in this area aim to disentangle the neural mechanisms underlying susceptibility to stress and their impact and relationship with cognitive processes known to influence mental health vulnerability.

Mapping Risk from Genes to Behavior: The Enduring and Evolving Influence of Irving Gottesman's Endophenotype Concept

One of Irving I. Gottesman's many contributions to behavior genetics, and part of his enduring legacy, was his introduction of the term 'endophenotype' to the field of psychiatry. Gottesman argued that focusing on endophenotypes, rather than complex heterogeneous clinical diagnoses, could help elucidate disease etiology. Although a different strategy for gene identification ultimately proved successful (that of amassing extremely large sample sizes in order to overcome the 'noise' of heterogeneity and have sufficient power to find genes of very small effect), the endophenotype concept continues to make a meaningful contribution to the field. The endophenotype concept forced the field to move beyond a simple disease model of finding genes 'for' psychiatric outcomes, and reminded us that genes are quite distal from complex behavioral outcomes and disorders. Endophenotypes called our attention to the steps along that pathway. In that process, the concept of endophenotypes evolved and expanded to include discussion of the role that other intermediary traits and psychological processes play in the development and genetic etiology of psychiatric and substance use disorders. As large-scale consortia continues to identify genes and generate genome-wide polygenic scores that are associated with behavioral outcomes, the next important step will be to characterize the pathways and mechanisms by which genetic risk unfolds. This essential step of mapping risk from genes to behavior is an evolution that follows naturally from the endophenotype concept, and could ultimately translate into improved prevention and intervention for individuals who are pre-disposed to mental health challenges.

Masked ambiguity - Emotion identification in schizophrenia and major depressive disorder

Both patients with schizophrenia and with a major depressive disorder (MDD) display deficits in identifying facial expressions of emotion during acute phases of their illness. However, specific deficit patterns have not yet been reliably demonstrated. Tasks that employ emotionally ambiguous stimuli have recently shown distinct deficit patterns in patients with schizophrenia compared to other mental disorders as well as healthy controls. We here investigate whether a task which uses an ambiguous Japanese (Noh) mask and a corresponding human stimulus generates distinctive emotion attribution patterns in thirty-two Caucasian patients with schizophrenia, matched MDD patients and healthy controls. Results show that patients with schizophrenia displayed reaction time disadvantages compared to healthy controls while identifying sadness and anger. MDD patients were more likely to label stimuli with basic compared to subtle emotional expressions. Moreover, they showed more difficulties assigning emotions to the human stimulus than to the Noh mask. IQ, age and cognitive functioning did not modulate these results. Because overall group differences were not observed, this task is not suitable for diagnosing patients. However, the subtle differences that did emerge might give therapists handles that can be used in therapy.

A Family Study of the DSM-5 Section III Personality Pathology Model Using the Personality Inventory for the DSM-5 (PID-5)

In Section III of the DSM-5, the American Psychiatric Association (APA) proposes a pathological personality trait model of personality disorders. The recommended assessment instrument is the Personality Inventory for the DSM-5 (PID-5), an empirically derived scale that assesses personality pathology along five domains and 25 facets. Although the PID-5 demonstrates strong convergent validity with other personality measures, no study has examined whether it identifies traits that run in families, another important step toward validating the DSM-5's dimensional model. Using a family study method, we investigated familial associations of PID-5 domain and facet scores in 195 families, examining associations between parents and offspring and across siblings. The Psychoticism, Antagonism, and Detachment domains showed significant familial aggregation, as did facets of Negative Affect and Disinhibition. Results are discussed in the context of personality pathology and family study methodology. The results also help validate the PID-5, given the familial nature of personality traits.

The role of inflammation in core features of depression: Insights from paradigms using exogenously-induced inflammation

A wealth of evidence has implicated inflammation in the development of depression. Yet, the heterogeneous nature of depression has impeded efforts to understand, prevent, and treat the disease. The purpose of this integrative review is to summarize the connections between inflammation and established core features of depression that exhibit more homogeneity than the syndrome itself: exaggerated reactivity to negative information, altered reward processing, decreased cognitive control, and somatic syndrome. For each core feature, we first provide a brief overview of its relevance to depression and neurobiological underpinnings, and then review evidence investigating a potential role of inflammation. We focus primarily on findings from experimental paradigms of exogenously-induced inflammation. We conclude that inflammation likely plays a role in exaggerated reactivity to negative information, altered reward reactivity, and somatic symptoms. There is less evidence supporting an effect of inflammation on cognitive control as assessed by standard neuropsychological measures. Finally, we discuss implications for future research and recommendationsfor how to test the role of inflammation in the pathogenesis of heterogeneous psychiatric disorders.

Translational research in psychiatry: The Research Domain Criteria Project (RDoC)

Despite the consensus achieved in the homogenization of clinical criteria by categorical psychiatric classification systems (DEM and CIE), they are criticized for a lack of validity and inability to guide clinical treatment and research. In this review article we introduce the Research Domain Criteria (RDoC) framework as an alternative framework for translational research in psychiatry. The RDOC framework systematizes both research targets and methodology for research in psychiatry. RDoC is based on a catalogue of neurobiological and neurocognitive evidence of behaviour, and conceives psychopathology as the phenotypic expression of alterations of functional domains that are classified into 5psychobiological systems. The RdoC framework also proposes that domains must be validated with evidence in 7levels of analysis: genes, molecules, cells, nerve circuits, physiology, behaviour and self-reports. As opposed to categorical systems focused on diagnosis, RDoC focuses on the study of psychopathology as a correlate of detectable functional, biological and behavioural disruption of normal processes. In order to build a useful psychiatric nosology for guiding clinical interventions, the RDoC research framework links the neurobiological basis of mental processes with phenotypical manifestations. Although the RDoC findings have not yet been articulated into a specific model for guiding clinical practice, they provide a useful transition system for creating clinical, basic and epidemiological research hypotheses.

The Leiden Family Lab study on Social Anxiety Disorder: A multiplex, multigenerational family study on neurocognitive endophenotypes

OBJECTIVES

Social anxiety disorder (SAD) is a serious and prevalent psychiatric condition, with a heritable component. However, little is known about the characteristics that are associated with the genetic component of SAD, the so-called "endophenotypes". These endophenotypes could advance our insight in the genetic susceptibility to SAD, as they are on the pathway from genotype to phenotype. The Leiden Family Lab study on Social Anxiety Disorder (LFLSAD) is the first multiplex, multigenerational study aimed to identify neurocognitive endophenotypes of social anxiety.

METHODS

The LFLSAD is characterized by a multidisciplinary approach and encompasses a variety of measurements, including a clinical interview, functional and structural magnetic resonance imaging and an electroencephalography experiment. Participants are family members from 2 generations, from families genetically enriched for SAD.

RESULTS

The sample (n = 132 participants, from 9 families) was characterized by a high prevalence of SAD, in both generations (prevalence (sub)clinical SAD: 38.3%). Furthermore, (sub)clinical SAD was positively related to self-reported social anxiety, fear of negative evaluation, trait anxiety, behavioral inhibition, negative affect, and the level of depressive symptoms.

CONCLUSIONS

By the multidimensional character of the measurements and thorough characterization of the sample, the LFLSAD offers unique opportunities to investigate candidate neurocognitive endophenotypes of SAD.

Identifying auditory cortex encoding abnormalities in schizophrenia: The utility of low-frequency versus 40 Hz steady-state measures

Magnetoencephalography (MEG) and EEG have identified poststimulus low frequency and 40 Hz steady-state auditory encoding abnormalities in schizophrenia (SZ). Negative findings have also appeared. To identify factors contributing to these inconsistencies, healthy control (HC) and SZ group differences were examined in MEG and EEG source space and EEG sensor space, with better group differentiation hypothesized for source than sensor measures given greater predictive utility for source measures. Fifty-five HC and 41 chronic SZ were presented 500 Hz sinusoidal stimuli modulated at 40 Hz during simultaneous whole-head MEG and EEG. MEG and EEG source models using left and right superior temporal gyrus (STG) dipoles estimated trial-to-trial phase similarity and percent change from prestimulus baseline. Group differences in poststimulus low-frequency activity and 40 Hz steady-state response were evaluated. Several EEG sensor analysis strategies were also examined. Poststimulus low-frequency group differences were observed across all methods. Given an age-related decrease in left STG 40 Hz steady-state activity in HC (HC > SZ), 40 Hz steady-state group differences were evident only in younger participants' source measures. Findings thus indicated that optimal data collection and analysis methods depend on the auditory encoding measure of interest. In addition, whereas results indicated that HC and SZ auditory encoding low-frequency group differences are generally comparable across modality and analysis strategy (and thus not dependent on obtaining construct-valid measures of left and right auditory cortex activity), 40 Hz steady-state group-difference findings are much more dependent on analysis strategy, with 40 Hz steady-state source-space findings providing the best group differentiation.

Working Memory and Vigilance as Multivariate Endophenotypes Related to Common Genetic Risk for Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

Understanding the role of endophenotypes is essential for process models of psychopathology. This study examined which candidate cognitive endophenotypes statistically mediate common variant genetic risk for attention-deficit/hyperactivity disorder (ADHD).

METHOD

A case-control design using community-recruited volunteer children 7 to 11 years of age (n = 656, n = 435 ADHD), of whom 514 were of homogenous European ancestry for the primary models (n = 337 ADHD, 177 non-ADHD). Children were assessed with a multi-informant, best-estimate diagnostic procedure and laboratory measures of working memory, response inhibition, executive functioning, arousal/attention, temporal information processing, and processing speed. Latent variables were created for the candidate cognitive measures and for parent- and teacher-rated ADHD dimensions. Polygenic risk scores (PGS) were computed using a discovery sample of 20,183 individuals with ADHD and 35,191 controls from the Psychiatric Genetics Consortium. Cognitive measures that survived multiple testing correction for association with the PGS were evaluated for mediation with ADHD using structural equation models.

RESULTS

Results were essentially identical in the homogeneous European ancestry subgroup (n = 514) and in the full sample (N = 656). For the European population, the PGS was associated with ADHD diagnosis (Nagelkerke R2 = 0.045; β = 0.233, SE = 0.053, p = .000011) and multi-indicator dimensional ADHD latent variables by parent report (β = 0.185, SE = 0.043) and teacher report (β = 0.165, SE = 0.042). The PGS effect was statistically mediated by working memory (indirect effect, β = 0.101, SE = 0.029, 95% CI = 0.05, 0.16, p = .00049, 43% of genetic effect accounted for) and arousal/alertness (indirect effect β = 0.115, 95% CI = 0.04, 0.20, SE = 0.041, p = .005, 49% of genetic effect accounted for).

CONCLUSION

This is the first clear demonstration from molecular genetic data that working memory and arousal regulation are promising cognitive endophenotypes for ADHD with regard to mediating genetic risk from common genetic variants.

Conceptual endophenotypes: A strategy to advance the impact of psychoneuroendocrinology in precision medicine

Psychobiological research has generated a tremendous amount of findings on the psychological, neuroendocrine, molecular and environmental processes that are directly relevant for mental and physical health, but have overwhelmed our capacity to meaningfully absorb, integrate, and utilize this knowledge base. Here, we reflect about suitable strategies to improve the translational success of psychoneuroendocrinological research in the era of precision medicine. Following a strategy advocated by the National Research Council and the tradition of endophenotype-based research, we advance here a new approach, termed "conceptual endophenotypes". We define the contextual and formal criteria of conceptual endophenotypes, outline criteria for filtering and selecting information, and describe how conceptual endophenotypes can be validated and implemented at the bedside. As proof-of-concept, we describe some of our findings from research that has adopted this approach in the context of stress-related disorders. We argue that conceptual endophenotypes engineer a bridge between the bench and the bedside. This approach readily lends itself to being continuously developed and implemented. Recent methodological advances, including digital phenotyping, machine learning, grassroots collaboration, and a learning healthcare system, may accelerate the development and implementation of this conceptual endophenotype approach.

Misunderstanding RDoC

Mental illness is fundamentally mental, by definition about psychological rather than biological phenomena, but biological phenomena play key roles in understanding, preventing, and treating mental illness. The Research Domain Criteria initiative (RDoC) of the US National Institute of Mental Health is an unusually ambitious effort to foster integration of psychological and biological science in the service of psychopathology research. Some key features and common misunderstandings of RDoC are discussed here.

Behavioral and EEG responses to social evaluation: A two-generation family study on social anxiety

Social anxiety disorder is an invalidating psychiatric disorder characterized by extreme fear and avoidance of one or more social situations in which patients might experience scrutiny by others. The goal of this two-generation family study was to delineate behavioral and electrocortical endophenotypes of social anxiety disorder related to social evaluation. Nine families of patients with social anxiety disorder (their spouse and children, and siblings of these patients with spouse and children) performed a social judgment paradigm in which they believed to be evaluated by peers. For each peer, participants indicated their expectation about the evaluative outcome, after which they received social acceptance or rejection feedback. Task behavior, as well as the feedback-related EEG brain potentials (N1, FRN, P3) and theta power were tested as candidate endophenotypes based on two criteria: co-segregation with social anxiety disorder within families and heritability. Results indicated that reaction time for indicating acceptance-expectations might be a candidate behavioral endophenotype of social anxiety disorder, possibly reflecting increased uncertainty or self-focused attention and vigilance during the social judgment paradigm. N1 in response to expected rejection feedback and P3 in response to acceptance feedback might be candidate electrocortical endophenotypes of social anxiety disorder, although the heritability analyses did not remain significant after correcting for multiple tests. Increased N1 possibly reflects hypervigilance to socially threatening stimuli, and increased P3 might reflect that positive feedback is more important for, and/or less expected by, participants with social anxiety disorder. Finally, increased feedback-related negativity and theta power in response to unexpected rejection feedback compared to the other conditions co-segregated with social anxiety disorder, but these EEG measures were not heritable. The candidate endophenotypes might play a new and promising role in future research on genetic mechanisms, early detection and/or prevention of social anxiety disorder.