The p factor: genetic analyses support a general dimension of psychopathology in childhood and adolescence

Maternal depression and the polygenic p factor: A family perspective on direct and indirect effects

Within-family studies typically assess indirect genetic effects of parents on children, however social support theory points to a critical role of partners and children on women's depression. To address this research gap and account for the high heterogeneity of depression, we calculated a general psychiatric factor using eleven major psychiatric polygenic scores (polygenic p), in up to 25,000 parent-offspring trios from the Norwegian Mother, Father and Child Cohort Study (MoBa). Multilevel modeling of trio polygenic p was used to distinguish direct and indirect genetic effects on mothers depression during pregnancy (gestational age 17 and 30 weeks), infancy (6 months, 18 months) and early childhood (3 years, 5 years, and 8 years). We found mothers polygenic p predicts their depression symptoms (b = 0.092; 95 % CI [0.087,0.098]), outperforming prediction using a single major depressive disorder polygenic score (b = 0.070, 95 % CI [0.066,0.075]). Jointly modeling trio polygenic p revealed indirect genetic effects of fathers (b = 0.022, 95 % CI [0.014,0.030]) and children (b = 0.021, 95 % CI [0.010,0.037]) on mothers' depression. Our results support the generalizability of polygenic effects across mental health and highlight the role of close family members on women's depression.

The mediating effects of personality traits on the relationship of youth conduct problems and mood disorders with adulthood suicidality

Identifying the relevant factors for suicidality in individuals with conduct problems is a public health concern, especially if they were under the influence of mood disorders later in life. This study investigates the relationship between youth conduct problems and mood disorders and adulthood suicidality, and to further explore the mediating effects of personality on this relationship. A retrospective cohort study was administered to 308 individuals aged 20-65 years, with or without mood disorders diagnosed by psychiatrists. The Composite International Diagnosis Interview was used to evaluate conduct problems in youth and suicidality (i.e., suicide plan and suicide attempt) in the past year. Personality traits were assessed using Eysenck Personality Questionnaire-Revised for extraversion and neuroticism. Multiple-mediator analysis was used to investigate the mediation effects of personality traits on the relationship between conduct problems and suicidality. The average age of enrolled participants was 31.6 years, and 42.5% of them were female. 39.2% reported suicidality and 43.2% reported conduct problems in youth. Participants who were diagnosed with mood disorders (p < 0.001) and reported having conduct problems (p = 0.004) were associated with high suicidality. Multiple-mediator analysis showed that conduct problems in youth increased the risk of adulthood suicidality through the indirect effects of higher neuroticism (suicide plan: OR = 1.30, BCA 95% CI = 1.04-1.83; suicide attempt: OR = 1.27, BCA 95% CI = 1.05-1.66). Neuroticism mediates the association between youth conduct problems and adulthood suicidality. This finding raises our attention to assess personality traits in individuals with youth conduct problems for designing proper intervention strategies to reduce the risk of suicide.

Parent- and teacher-reported associations from adolescent bifactor models of psychopathology: an outcome-wide association study of 26 outcomes in mid-life

BACKGROUND

Adolescent mental health problems have lasting impacts on health and social functioning later in life. Evidence to date mostly comes from studies of specific diagnostic categories/dimensions, but hierarchical models can elucidate associations with general as well as specific dimensions of psychopathology. We provide evidence on long-term outcomes of general and specific dimensions of adolescent psychopathology using both parent and teacher reports.

METHODS

Parents and teachers from the Isle of Wight study completed Rutter behaviour scales when participants were 14-15 years old (n = 2,275), assessing conduct, emotional and hyperactivity problems. Metric-invariant bifactor models for parents and teachers were used to test domain-specific and domain-general associations with 26 self-reported psychosocial outcomes at mid-life (age 44-45 years, n = 1,423). Analyses examined the individual and joint contributions of parent and teacher reports of adolescent psychopathology. All analyses were adjusted for covariates (gender, IQ and family social class) and weighted to adjust for the probability of nonresponse.

RESULTS

Parent- and teacher-reported general factors of psychopathology (GFP) were associated with 15 and 12 outcomes, respectively, across the socioeconomic, relationship, health and personality domains, along with an index of social exclusion. Nine outcomes were associated with both parent- and teacher-reported GFP, with no differences in the strength of the associations across reporters. Teacher-reported specific factors (conduct, emotional and hyperactivity) were associated with 21 outcomes, and parent-reported specific factors were associated with seven. Five outcomes were associated with the same specific factors from both reporters; only one showed reporter differences in the strength of the associations.

CONCLUSIONS

These findings confirm the relevance of the GFP and the utility of teacher as well as parent reports of adolescent mental health in predicting psychosocial outcomes later in the life course.

Mutualistic processes in the development of psychopathology: The special case of borderline personality disorder

Borderline personality disorder (BPD) is a serious mental illness characterized by instability in affective, cognitive, and interpersonal domains. BPD co-occurs with several mental disorders and has robust, positive associations with the general factors of psychopathology (p-factor) and personality disorders (g-PD). Consequently, some researchers have purported BPD to be a marker of p, such that the core features of BPD reflect a generalized liability to psychopathology. This assertion has largely stemmed from cross-sectional evidence and no research to date has explicated the developmental relationships between BPD and p. The present study aimed to investigate the development of BPD traits and the p-factor by examining predictions of two opposing frameworks: dynamic mutualism theory and the common cause theory. Competing theories were evaluated to determine which perspective best accounted for the relationship of BPD and p from adolescence into young adulthood. Data were drawn from the Pittsburgh Girls Study (PGS; N = 2,450) and included yearly self-assessments of BPD and other internalizing and externalizing indices from ages 14 to 21. Theories were examined using random-intercept cross-lagged panel models (RI-CLPMs) and network models. Results indicated that neither dynamic mutualism nor the common cause theory could fully explain the developmental relations between BPD and p. Instead, both frameworks were partially supported, with p found to strongly predict within-person change in BPD at several ages. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Cingulate-Prefrontal Connectivity During Dynamic Cognitive Control Mediates Association Between p Factor and Adaptive Functioning in a Transdiagnostic Pediatric Sample

BACKGROUND

Covariation among psychiatric symptoms is being actively pursued for transdiagnostic dimensions of psychopathology with predictive utility. A superordinate dimension, the p factor, reflects overall psychopathology burden and has support from genetic and neuroimaging correlates. However, the neurocognitive correlates that link an elevated p factor to maladaptive outcomes are unknown. We tested the mediating potential of dynamic adjustments in cognitive control rooted in functional connections anchored by the dorsal anterior cingulate cortex (dACC) in a transdiagnostic pediatric sample.

METHODS

A multiple mediation model tested the association between the p factor (derived by principal component analysis of Child Behavior Checklist syndrome scales) and outcome measured with the Vineland Adaptive Behavior Scale-II in 89 children ages 8 to 13 years (23 female) with a variety of primary neurodevelopmental diagnoses who underwent functional magnetic resonance imaging during a socioaffective Stroop-like task with eye gaze as distractor. Mediators included functional connectivity of frontoparietal- and salience network-affiliated dACC seeds during conflict adaptation.

RESULTS

Higher p factor scores were related to worse adaptive functioning. This effect was partially mediated by conflict adaptation-dependent functional connectivity between the frontoparietal network-affiliated dACC seed and the right dorsolateral prefrontal cortex. Post hoc follow-up indicated that the p factor was related to all Vineland Adaptive Behaviors Scale-II domains; the association was strongest for socialization followed by daily living skills and then communication. Mediation results remained significant for socialization only.

CONCLUSIONS

Higher psychopathology burden was associated with worse adaptive functioning in early adolescence. This association was mediated by weaker dACC-dorsolateral prefrontal cortex functional connectivity underlying modulation of cognitive control in response to contextual contingencies. Our results contribute to the identification of transdiagnostic and developmentally relevant neurocognitive endophenotypes of psychopathology.

An integrative evolutionary framework for psychopathology

The field of psychopathology is in a transformative phase, and is witnessing a renewed surge of interest in theoretical models of mental disorders. While many interesting proposals are competing for attention in the literature, they tend to focus narrowly on the proximate level of analysis and lack a broader understanding of biological function. In this paper, we present an integrative framework for mental disorders built on concepts from life history theory, and describe a taxonomy of mental disorders based on its principles, the fast-slow-defense model (FSD). The FSD integrates psychopathology with normative individual differences in personality and behavior, and allows researchers to draw principled distinctions between broad clusters of disorders, as well as identify functional subtypes within current diagnostic categories. Simulation work demonstrates that the model can explain the large-scale structure of comorbidity, including the apparent emergence of a general "p factor" of psychopathology. A life history approach also provides novel integrative insights into the role of environmental risk/protective factors and the developmental trajectories of various disorders.

Meta-analysis of structural evidence for the Hierarchical Taxonomy of Psychopathology (HiTOP) model

BACKGROUND

The Hierarchical Taxonomy of Psychopathology (HiTOP) is a classification system that seeks to organize psychopathology using quantitative evidence - yet the current model was established by narrative review. This meta-analysis provides a quantitative synthesis of literature on transdiagnostic dimensions of psychopathology to evaluate the validity of the HiTOP framework.

METHODS

Published studies estimating factor-analytic models from diagnostic and statistical manual of mental disorders (DSM) diagnoses were screened. A total of 120,596 participants from 35 studies assessing 23 DSM diagnoses were included in the meta-analytic models. Data were pooled into a meta-analytic correlation matrix using a random effects model. Exploratory factor analyses were conducted using the pooled correlation matrix. A hierarchical structure was estimated by extracting one to five factors representing levels of the HiTOP framework, then calculating congruence coefficients between factors at sequential levels.

RESULTS

Five transdiagnostic dimensions fit the DSM diagnoses well (comparative fit index = 0.92, root mean square error of approximation = 0.07, and standardized root-mean-square residual = 0.03). Most diagnoses had factor loadings >|0.30| on the expected factors, and congruence coefficients between factors indicated a hierarchical structure consistent with the HiTOP framework.

CONCLUSIONS

A model closely resembling the HiTOP framework fit the data well and placement of DSM diagnoses within transdiagnostic dimensions were largely confirmed, supporting it as valid structure for conceptualizing and organizing psychopathology. Results also suggest transdiagnostic research should (1) use traits, narrow symptoms, and dimensional measures of psychopathology instead of DSM diagnoses, (2) assess a broader array of constructs, and (3) increase focus on understudied pathologies.

The shared genetic architecture of suicidal behaviour and psychiatric disorders: A genomic structural equation modelling study

Background: Suicidal behaviour (SB) refers to behaviours, ranging from non-fatal suicidal behaviour, such as suicidal ideation and attempt, to completed suicide. Despite recent advancements in genomic technology and statistical methods, it is unclear to what extent the spectrum of suicidal behaviour is explained by shared genetic aetiology. Methods: We identified nine genome-wide association statistics of suicidal behaviour (sample sizes, n, ranging from 62,648 to 125,844), ten psychiatric traits [n up to 386,533] and collectively, nine summary datasets of anthropometric, behavioural and socioeconomic-related traits [n ranging from 58,610 to 941,280]. We calculated the genetic correlation among these traits and modelled this using genomic structural equation modelling, identified shared biological processes and pathways between suicidal behaviour and psychiatric disorders and evaluated potential causal associations using Mendelian randomisation. Results: Among populations of European ancestry, we observed strong positive genetic correlations between suicide ideation, attempt and self-harm (rg range, 0.71-1.09) and moderate to strong genetic correlations between suicidal behaviour traits and a range of psychiatric disorders, most notably, major depression disorder (rg = 0.86, p = 1.62 × 10^-36). Multivariate analysis revealed a common factor structure for suicidal behaviour traits, major depression, attention deficit hyperactivity disorder (ADHD) and alcohol use disorder. The derived common factor explained 38.7% of the shared variance across the traits. We identified 2,951 genes and 98 sub-network hub genes associated with the common factor, including pathways associated with developmental biology, signal transduction and RNA degradation. We found suggestive evidence for the protective effects of higher household income level on suicide attempt [OR = 0.55 (0.44-0.70), p = 1.29 × 10^-5] and while further investigation is needed, a nominal significant effect of smoking on suicide attempt [OR = 1.24 (1.04-1.44), p = 0.026]. Conclusion: Our findings provide evidence of shared aetiology between suicidal behaviour and psychiatric disorders and indicate potential common molecular mechanisms contributing to the overlapping pathophysiology. These findings provide a better understanding of the complex genetic architecture of suicidal behaviour and have implications for the prevention and treatment of suicidal behaviour.

The harmonium model and its unified system view of psychopathology: a validation study by means of a convolutional neural network

The harmonium model (HM) is a recent conceptualization of the unifying view of psychopathology, namely the idea of a general mechanism underpinning all mental disorders (the p factor). According to HM, psychopathology consists of a low dimensional Phase Space of Meaning (PSM), where each dimension of meaning maps a component of the environmental variability. Accordingly, the lower thenumber of independent dimensions in the PSM, and hence its intrinsic complexity, the more limited the way of interpreting the environment. The current simulation study, based on a Convolutional Neural Network (CNN) framework, aims at validating the HM low-dimensionality hypothesis. CNN-based classifiers were employed to simulate normotypical and pathological cognitive processes. Results revealed that normotypical and pathological CNNs were different in terms of both classification performance and layer activation patterns. Using Principal Component Analysis to characterize the PSM associated with the two algorithms, we found that the performance of the normotypical CNN relies on a larger and more evenly distributed number of components, compared with the pathological one. This finding might be indicative of the fact that psychopathology can be modelled as a low-dimensional, poorly modulable PSM, which means the environment is detected through few components of meaning, preventing complex information patterns from being taken into account.

Intergenerational transmission of psychopathology: An examination of symptom severity and directionality

The present study examined the intergenerational transmission of internalizing and externalizing symptom severity, which indexes comorbidity, and symptom directionality, which indicates differentiation toward externalizing versus internalizing problems. Data are from 854 male and female, same-sex adult twin pairs born between 1926 and 1971 (32-60 years old, M = 44.9 years, SD = 4.9 years) from the Twin and Offspring Study in Sweden and their adolescent offspring (11-22 years old, M = 15.7 years, SD = 2.4 years, 52% female). Children-of-twins models revealed additive (9%) and dominant (45%) genetic and nonshared environmental (47%) influences on twins' symptom severity, and additive genetic (39%) and nonshared environmental (61%) influences on twins' symptom directionality. Both comorbid problems and preponderance of symptoms of a particular - internalizing versus externalizing - spectrum were correlated across parent and child generations, although associations were modest especially for directionality (i.e., transmission of specific symptom type). By interpreting findings alongside a recent study of adolescent twins, we demonstrate that the intergenerational transmission of symptom severity and symptom directionality are both unlikely to be attributable to genetic transmission, are both likely to be influenced by direct phenotypic transmission and/or nonpassive rGE, and the intergenerational transmission of symptom severity is also likely to be influenced by passive rGE.

Associations between psychiatric polygenic risk scores and general and specific psychopathology symptoms in childhood and adolescence between and within dizygotic twin pairs

BACKGROUND

Although polygenic risk scores (PRS) predict psychiatric problems, these associations might be attributable to indirect pathways including population stratification, assortative mating, or dynastic effects (mediation via parental environments). The goal of this study was to examine whether PRS-psychiatric symptom associations were attributable to indirect versus direct pathways.

METHODS

The sample consisted of 3,907 dizygotic (DZ) twin pairs. In childhood, their parents rated them on 98 symptoms. In adolescence (n = 2,393 DZ pairs), both the parents and the twins rated themselves on 20 symptoms. We extracted one general and seven specific factors from the childhood data, and one general and three specific factors from the adolescent data. We then regressed each general factor model onto ten psychiatric PRS simultaneously. We first conducted the regressions between individuals (β) and then within DZ twin pairs (βw ), which controls for indirect pathways.

RESULTS

In childhood, the PRS for ADHD predicted general psychopathology (β = 0.09, 95% CI: [0.06, 0.12]; βw  = 0.07 [0.01, 0.12]). Furthermore, the PRS for ADHD predicted specific inattention (β = 0.04 [0.00, 0.08]; βw  = 0.09 [0.01, 0.17]) and specific hyperactivity (β = 0.07 [0.04, 0.11]; βw  = 0.09 [0.01, 0.16]); the PRS for schizophrenia predicted specific learning (β = 0.08 [0.03, 0.13]; βw  = 0.19 [0.08, 0.30]) and specific inattention problems (β = 0.05 [0.01, 0.09]; βw  = 0.10 [0.02, 0.19]); and the PRS for neuroticism predicted specific anxiety (β = 0.06 [0.02, 0.10]; βw  = 0.06 [0.00, 0.12]). Overall, the PRS-general factor associations were similar between individuals and within twin pairs, whereas the PRS-specific factors associations amplified by 84% within pairs.

CONCLUSIONS

This implies that PRS-psychiatric symptom associations did not appear attributable to indirect pathways such as population stratification, assortative mating, or mediation via parental environments. Rather, genetics appeared to directly influence symptomatology.

The Promise and Peril of Genetics

Human genetics is advancing at an unprecedented pace. Improvements in genotyping technology and rapidly falling costs have accelerated gene discovery. We can now comprehensively scan the genome, testing variation across millions of genetic markers, to identify specific variants associated with any outcome of interest. Large consortia consisting of hundreds of scientists are analyzing data from hundreds of thousands to millions of individuals. Multivariate methods now enable us to identify genes involved in underlying processes, to complement studies focused on specific disorders or traits. There has been an exponential increase in use of direct-to-consumer genetic feedback platforms. These advances are poised to have a widespread effect on medicine and society. However, with such rapid progress will come ethical, social, and legal challenges. Among those challenges is the need for increased efforts to enhance public understanding of the ways genes contribute to complex behavioral outcomes, and for increased diversity in the field of genetics to ensure that all people benefit from advances. Psychologists can play an important role in addressing the inevitable questions that will arise as genetics increasingly becomes mainstream.

The next 10 years of behavioural genomic research

Background

The explosion caused by the fusion of quantitative genetics and molecular genetics will transform behavioural genetic research in child and adolescent psychology and psychiatry.

Methods

Although the fallout has not yet settled, the goal of this paper is to predict the next 10 years of research in what could be called behavioural genomics.

Results

I focus on three research directions: the genetic architecture of psychopathology, causal modelling of gene-environment interplay, and the use of DNA as an early warning system.

Conclusion

Eventually, whole-genome sequencing will be available for all newborns, which means that behavioural genomics could potentially be applied ubiquitously in research and clinical practice.

Connectome-wide Functional Connectivity Abnormalities in Youth With Obsessive-Compulsive Symptoms

BACKGROUND

Obsessive-compulsive symptomatology (OCS) is common in adolescence but usually does not meet the diagnostic threshold for obsessive-compulsive disorder. Nevertheless, both obsessive-compulsive disorder and subthreshold OCS are associated with increased likelihood of experiencing other serious psychiatric conditions, including depression and suicidal ideation. Unfortunately, there is limited information on the neurobiology of OCS.

METHODS

Here, we undertook one of the first brain imaging studies of OCS in a large adolescent sample (analyzed n = 832) from the Philadelphia Neurodevelopmental Cohort. We investigated resting-state functional magnetic resonance imaging functional connectivity using complementary analytic approaches that focus on different neuroanatomical scales, from known functional systems to connectome-wide tests.

RESULTS

We found a robust pattern of connectome-wide, OCS-related differences, as well as evidence of specific abnormalities involving known functional systems, including dorsal and ventral attention, frontoparietal, and default mode systems. Analysis of cerebral perfusion imaging and high-resolution structural imaging did not show OCS-related differences, consistent with domain specificity to functional connectivity.

CONCLUSIONS

The brain connectomic associations with OCS reported here, together with early studies of its clinical relevance, support the potential for OCS as an early marker of psychiatric risk that may enhance our understanding of mechanisms underlying the onset of adolescent psychopathology.

Empirical support for a dual process model of the p-factor: Interaction effects between preschool executive control and preschool negative emotionality on general psychopathology

Recent work indicates that a general factor, often referred to as the p-factor, underlies nearly all forms of psychopathology. Although the criterion validity and utility of this general factor have been well supported, questions remain about the substantive meaning of the p-factor. The purpose of the present longitudinal study was to empirically test the hypothesis that the p-factor reflects dysregulation arising from a combination of high dispositional negative emotionality and low executive control. The current study examined preschool executive control, measured using a battery of 9 developmentally appropriate executive control tasks, as a moderator of the association between preschool negative emotionality and both concurrent and subsequent levels of general psychopathology in preschool and elementary school using a community sample (N = 497). Latent moderated structural equation models demonstrated that preschool executive control significantly moderated the associations between preschool negative emotionality and general psychopathology both in preschool and approximately 5 years later in elementary school. These results suggest that the general factor of psychopathology may reflect dysregulation arising from a tendency to experience high negative affect, without sufficient executive control to effectively down-regulate that affect. This work has important implications for identifying transdiagnostic targets for prevention and intervention efforts, as well as furthering understanding of the substantive meaning and construct validity of the general factor of psychopathology. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Long- term remission status in pediatric obsessive-compulsive disorder: Evaluating the predictive value of symptom severity after treatment

It is unknown if long-term remission for pediatric obsessive-compulsive disorder (OCD) patients is associated with post-treatment OCD symptom severity. The aim of the present study was to evaluate if post-treatment symptom severity cut-offs can discriminate remitters from non-remitters in pediatric OCD patients during three years of follow-up. All participants (N = 269) from the Nordic Long-term OCD Treatment Study (NordLOTS) undergoing stepped-care treatment were included. Patients were rated with the Clinical Global Impression - Severity Scale (CGI-S) one (n = 186), two (n = 167), and three years (n = 166) after first-line cognitive-behavioral therapy. Post-treatment symptom severity scores as well as percentage reductions during treatment evaluated with the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) were analyzed using receiver operating characteristics according to the CGI-S remission scores (< 2) at follow-up. Post-treatment CY-BOCS severity scores acceptably discriminated remitters from non-remitters at one-year follow-up, but poorly for the two- and three-year follow-up. Severity percentage reduction during treatment did not discriminate remission status acceptably at any follow-up point. Post-treatment OCD symptom severity status seems to have little discriminative value for long-term remission status in pediatric patients. Further research is warranted to detect post-treatment factors of prognostic value.

Genetic variance in conscientiousness relates to youth psychopathology beyond executive functions

Because deficits in self-regulation (SR) are core features of many diverse psychological disorders, SR may constitute one of many dimensions that underlie shared variance across diagnostic boundaries (e.g., the p factor, a dimension reflecting shared variance across multiple psychological disorders). SR definitions encompass constructs mapping onto different theoretical traditions and different measurement approaches, however. Two SR operationalizations, executive functioning and conscientiousness, are often used interchangeably despite their low empirical associations-a "jingle" fallacy that pervades much of the research on SR-psychopathology relationships. In a population-based sample of 1,219 twins and multiples from the Texas Twin Project (Mage = 10.60, SDage = 1.76), with a comprehensive battery of measures, we aimed to clarify how these often-muddled aspects of SR relate to individual differences in psychopathology, and whether links between them are accounted for by overlapping genetic and environmental factors. The p factor and an Attention Problems-specific factor were associated with lower executive functioning and conscientiousness. Executive functioning shared a small amount of genetic variance with p above and beyond conscientiousness, whereas conscientiousness shared substantial genetic variance with p independently of genetic variance accounted for by executive functioning. Conversely, the Attention Problems-specific factor was strongly genetically associated with executive functioning independently of genetic variance accounted for by conscientiousness. Results support the notion that SR and psychopathology, broadly conceived, may exist on overlapping spectra, but this overlap varies across conceptualizations of SR and the level of specificity at which psychopathology is assessed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Research Review: A guide to computing and implementing polygenic scores in developmental research

The increasing availability of genotype data in longitudinal population- and family-based samples provides opportunities for using polygenic scores (PGS) to study developmental questions in child and adolescent psychology and psychiatry. Here, we aim to provide a comprehensive overview of how PGS can be generated and implemented in developmental psycho(patho)logy, with a focus on longitudinal designs. As such, the paper is organized into three parts: First, we provide a formal definition of polygenic scores and related concepts, focusing on assumptions and limitations. Second, we give a general overview of the methods used to compute polygenic scores, ranging from the classic approach to more advanced methods. We include recommendations and reference resources available to researchers aiming to conduct PGS analyses. Finally, we focus on the practical applications of PGS in the analysis of longitudinal data. We describe how PGS have been used to research developmental outcomes, and how they can be applied to longitudinal data to address developmental questions.

Differentiated nomological networks of internalizing, externalizing, and the general factor of psychopathology ('p factor') in emerging adolescence in the ABCD study

BACKGROUND

Structural models of psychopathology consistently identify internalizing (INT) and externalizing (EXT) specific factors as well as a superordinate factor that captures their shared variance, the p factor. Questions remain, however, about the meaning of these data-driven dimensions and the interpretability and distinguishability of the larger nomological networks in which they are embedded.

METHODS

The sample consisted of 10 645 youth aged 9-10 years participating in the multisite Adolescent Brain and Cognitive Development (ABCD) Study. p, INT, and EXT were modeled using the parent-rated Child Behavior Checklist (CBCL). Patterns of associations were examined with variables drawn from diverse domains including demographics, psychopathology, temperament, family history of substance use and psychopathology, school and family environment, and cognitive ability, using instruments based on youth-, parent-, and teacher-report, and behavioral task performance.

RESULTS

p exhibited a broad pattern of statistically significant associations with risk variables across all domains assessed, including temperament, neurocognition, and social adversity. The specific factors exhibited more domain-specific patterns of associations, with INT exhibiting greater fear/distress and EXT exhibiting greater impulsivity.

CONCLUSIONS

In this largest study of hierarchical models of psychopathology to date, we found that p, INT, and EXT exhibit well-differentiated nomological networks that are interpretable in terms of neurocognition, impulsivity, fear/distress, and social adversity. These networks were, in contrast, obscured when relying on the a priori Internalizing and Externalizing dimensions of the CBCL scales. Our findings add to the evidence for the validity of p, INT, and EXT as theoretically and empirically meaningful broad psychopathology liabilities.

Early childhood developmental vulnerability associated with parental mental disorder comorbidity

OBJECTIVES

Parental mental health has a profound influence on the mental health and well-being of their offspring. With comorbid mental disorders generally the rule rather than the exception, increased knowledge of the impact of parental mental disorder comorbidity on early child development may facilitate improved targeting and delivery of early intervention for vulnerable offspring.

METHODS

Participants were 66,154 children and their parents in the New South Wales Child Development Study - a prospective, longitudinal, record-linkage study of a population cohort of children born in NSW between 2002 and 2004. Early childhood developmental vulnerability was assessed at age ~5 years using the Australian Early Development Census, and information on parental mental disorders was obtained from administrative health records. Binomial and multinomial logistic regression were used to assess the relationship between parental mental disorders and early childhood developmental vulnerability on emotional and behavioural domains, as well as membership of latent developmental risk classes reflecting particular classes of vulnerability.

RESULTS

Multiple diagnoses of mental disorders in mothers and fathers were associated with an increased likelihood of early childhood emotional and behavioural developmental vulnerability in offspring, relative to parents without mental disorder. The likelihood of offspring vulnerability increased with the number of parental comorbidities, particularly maternal comorbidities.

CONCLUSION

Early childhood developmental vulnerability was strongly associated with parental mental ill-health, with the strength of associations increasing in line with a greater number of mental disorder diagnoses among mothers and fathers. New and expectant parents diagnosed with multiple mental disorders should be prioritised for intervention, including attention to the developmental well-being of their offspring.

Infant temperament prospectively predicts general psychopathology in childhood

Recent models of psychopathology suggest the presence of a general factor capturing the shared variance among all symptoms along with specific psychopathology factors (e.g., internalizing and externalizing). However, few studies have examined predictors that may serve as transdiagnostic risk factors for general psychopathology from early development. In the current study we examine, for the first time, whether observed and parent-reported infant temperament dimensions prospectively predict general psychopathology as well as specific psychopathology dimensions (e.g., internalizing and externalizing) across childhood. In a longitudinal cohort (N = 291), temperament dimensions were assessed at 4 months of age. Psychopathology symptoms were assessed at 7, 9, and 12 years of age. A bifactor model was used to estimate general, internalizing, and externalizing psychopathology factors. Across behavioral observations and parent-reports, higher motor activity in infancy significantly predicted greater general psychopathology in mid to late childhood. Moreover, low positive affect was predictive of the internalizing-specific factor. Other temperament dimensions were not related with any of the psychopathology factors after accounting for the general psychopathology factor. The results of this study suggest that infant motor activity may act as an early indicator of transdiagnostic risk. Our findings inform the etiology of general psychopathology and have implications for the early identification for children at risk for psychopathology.

The consequences of a year of the COVID-19 pandemic for the mental health of young adult twins in England and Wales

BACKGROUND

The COVID-19 pandemic has affected all our lives, not only through the infection itself but also through the measures taken to control the spread of the virus (e.g. lockdown).

AIMS

Here, we investigated how the COVID-19 pandemic and unprecedented lockdown affected the mental health of young adults in England and Wales.

METHOD

We compared the mental health symptoms of up to 4773 twins in their mid-20s in 2018 prior to the COVID-19 pandemic (T1) and during four-wave longitudinal data collection during the pandemic in April, July and October 2020, and in March 2021 (T2-T5) using phenotypic and genetic longitudinal designs.

RESULTS

The average changes in mental health were small to medium and mainly occurred from T1 to T2 (average Cohen d = 0.14). Despite the expectation of catastrophic effects of the pandemic on mental health, we did not observe trends in worsening mental health during the pandemic (T3-T5). Young people with pre-existing mental health problems were disproportionately affected at the beginning of the pandemic, but their increased problems largely subsided as the pandemic persisted. Twin analyses indicated that the aetiology of individual differences in mental health symptoms did not change during the lockdown (average heritability 33%); the average genetic correlation between T1 and T2-T5 was 0.95, indicating that genetic effects before the pandemic were substantially correlated with genetic effects up to a year later.

CONCLUSIONS

We conclude that on average the mental health of young adults in England and Wales has been remarkably resilient to the effects of the pandemic and associated lockdown.

Genome-wide Association Meta-analysis of Childhood and Adolescent Internalizing Symptoms

OBJECTIVE

To investigate the genetic architecture of internalizing symptoms in childhood and adolescence.

METHOD

In 22 cohorts, multiple univariate genome-wide association studies (GWASs) were performed using repeated assessments of internalizing symptoms, in a total of 64,561 children and adolescents between 3 and 18 years of age. Results were aggregated in meta-analyses that accounted for sample overlap, first using all available data, and then using subsets of measurements grouped by rater, age, and instrument.

RESULTS

The meta-analysis of overall internalizing symptoms (INToverall) detected no genome-wide significant hits and showed low single nucleotide polymorphism (SNP) heritability (1.66%, 95% CI = 0.84-2.48%, neffective = 132,260). Stratified analyses indicated rater-based heterogeneity in genetic effects, with self-reported internalizing symptoms showing the highest heritability (5.63%, 95% CI = 3.08%-8.18%). The contribution of additive genetic effects on internalizing symptoms appeared to be stable over age, with overlapping estimates of SNP heritability from early childhood to adolescence. Genetic correlations were observed with adult anxiety, depression, and the well-being spectrum (|rg| > 0.70), as well as with insomnia, loneliness, attention-deficit/hyperactivity disorder, autism, and childhood aggression (range |rg| = 0.42-0.60), whereas there were no robust associations with schizophrenia, bipolar disorder, obsessive-compulsive disorder, or anorexia nervosa.

CONCLUSION

Genetic correlations indicate that childhood and adolescent internalizing symptoms share substantial genetic vulnerabilities with adult internalizing disorders and other childhood psychiatric traits, which could partially explain both the persistence of internalizing symptoms over time and the high comorbidity among childhood psychiatric traits. Reducing phenotypic heterogeneity in childhood samples will be key in paving the way to future GWAS success.

How Robust Is the p Factor? Using Multitrait-Multimethod Modeling to Inform the Meaning of General Factors of Youth Psychopathology

We used multitrait-multimethod (MTMM) modeling to examine general factors of psychopathology in three samples of youth (Ns = 2119, 303, 592) for whom three informants reported on the youth's psychopathology (e.g., child, parent, teacher). Empirical support for the p-factor diminished in multi-informant models compared with mono-informant models: the correlation between externalizing and internalizing factors decreased and the general factor in bifactor models essentially reflected externalizing. Widely used MTMM-informed approaches for modeling multi-informant data cannot distinguish between competing interpretations of the patterns of effects we observed, including that the p-factor reflects, in part, evaluative consistency bias or that psychopathology manifests differently across contexts (e.g., home vs. school). Ultimately, support for the p-factor may be stronger in mono-informant designs, although it is does not entirely vanish in multi-informant models. Instead, the general factor of psychopathology in any given mono-informant model likely reflects a complex mix of variances, some substantive and some methodological.

Using DNA to predict behaviour problems from preschool to adulthood

BACKGROUND

One goal of the DNA revolution is to predict problems in order to prevent them. We tested here if the prediction of behaviour problems from genome-wide polygenic scores (GPS) can be improved by creating composites across ages and across raters and by using a multi-GPS approach that includes GPS for adult psychiatric disorders as well as for childhood behaviour problems.

METHOD

Our sample included 3,065 genotyped unrelated individuals from the Twins Early Development Study who were assessed longitudinally for hyperactivity, conduct, emotional problems, and peer problems as rated by parents, teachers, and children themselves. GPS created from 15 genome-wide association studies were used separately and jointly to test the prediction of behaviour problems composites (general behaviour problems, externalising, and internalising) across ages (from age 2 to 21) and across raters in penalised regression models. Based on the regression weights, we created multi-trait GPS reflecting the best prediction of behaviour problems. We compared GPS prediction to twin heritability using the same sample and measures.

RESULTS

Multi-GPS prediction of behaviour problems increased from <2% of the variance for observed traits to up to 6% for cross-age and cross-rater composites. Twin study estimates of heritability, although to a lesser extent, mirrored patterns of multi-GPS prediction as they increased from <40% to 83%.

CONCLUSIONS

The ability of GPS to predict behaviour problems can be improved by using multiple GPS, cross-age composites and cross-rater composites, although the effect sizes remain modest, up to 6%. Our approach can be used in any genotyped sample to create multi-trait GPS predictors of behaviour problems that will be more predictive than polygenic scores based on a single age, rater, or GPS.

A Systematic Review of Longitudinal Studies Investigating the Association Between Early Life Maternal Depression and Offspring ADHD

OBJECTIVE

The systematic review sought to understand the relationship between maternal depression and later ADHD in children.

METHOD

Three databases were used to identify the studies (Medline, Web of Science and PsychInfo) resulting in 1,223 studies being screened and 14 articles being included in the review.

RESULTS

The majority of studies (N = 11) reported a significant relationship between maternal depression (across both prenatal and postnatal periods) and ADHD symptoms in children. This relationship remained significant when temperament, or past ADHD symptoms were controlled for. Several methodological issues were identified including; overreliance on maternal report and parental ADHD not being accounted for in most studies.

CONCLUSION

The review adds to the literature regarding the temporal relationship between maternal depression and the development of ADHD in children, and thus supports the case for improving access to mental health services for mothers as a preventative strategy in the development of child psychopathology.

Mental disorders into adulthood among adolescents placed in residential care: A prospective 10-year follow-up study

BACKGROUND

Child welfare and juvenile justice placed youths show high levels of psychosocial burden and high rates of mental disorders. It remains unclear how mental disorders develop into adulthood in these populations. The aim was to present the rates of mental disorders in adolescence and adulthood in child welfare and juvenile justice samples and to examine their mental health trajectories from adolescence into adulthood.

METHODS

Seventy adolescents in shared residential care, placed by child welfare (n = 52, mean age = 15 years) or juvenile justice (n = 18, mean age = 17 years) authorities, were followed up into adulthood (child welfare: mean age = 25 years; juvenile justice: mean age = 27 years). Mental disorders were assessed based on the International Classification of Diseases 10th Revision diagnoses at baseline and at follow-up. Epidemiological information on mental disorders was presented for each group. Bivariate correlations and structural equation modeling for the relationship of mental disorders were performed.

RESULTS

In the total sample, prevalence rates of 73% and 86% for any mental disorder were found in adolescence (child welfare: 70%; juvenile justice: 83%) and adulthood (child welfare: 83%; juvenile justice: 94%) respectively. General psychopathology was found to be stable from adolescence into adulthood in both samples.

CONCLUSIONS

Our findings showed high prevalence rates and a high stability of general psychopathology into adulthood among child welfare and juvenile justice adolescents in Swiss residential care. Therefore, continuity of mental health care and well-prepared transitions into adulthood for such individuals is highly warranted.

Profiles in Criminal Psychopathology: A Multiple Case Report Study of the p Factor

(1) Background: The one general psychopathology (p Factor) theory asserts that a superordinate dimensional construct encompasses underlying forms of psychopathology, but the theory has limited empirical linkages to criminology. (2) Methods: We utilized case reports from 12 male offenders selected from a federal jurisdiction in the central United States who were in the 99th percentile on a composite indicator of psychopathology to advance a qualitative study of the p Factor. (3) Results: Clients experienced frequent and often pathological traumatic experiences and exhibited exceedingly early onset of conduct problems usually during the preschool period. Their criminal careers were overwhelmingly versatile and contained numerous offense types, had extensive justice system contacts, and exhibited remarkable deficits in global functioning. Most clients spent the majority of their life in local, state, or federal confinement. Consistent with the theory, clients experienced a generalized psychopathology disposition that had undercurrents of externalizing, internalizing, psychotic, paraphilic, and homicidal features. (4) Conclusions: A qualitative understanding of the p Factor and its contribution to offending behaviors among correctional clients complements the statistical approach to developmental psychopathology.

Combined polygenic risk scores of different psychiatric traits predict general and specific psychopathology in childhood

BACKGROUND

Polygenic risk scores (PRSs) operationalize genetic propensity toward a particular mental disorder and hold promise as early predictors of psychopathology, but before a PRS can be used clinically, explanatory power must be increased and the specificity for a psychiatric domain established. To enable early detection, it is crucial to study these psychometric properties in childhood. We examined whether PRSs associate more with general or with specific psychopathology in school-aged children. Additionally, we tested whether psychiatric PRSs can be combined into a multi-PRS score for improved performance.

METHODS

We computed 16 PRSs based on GWASs of psychiatric phenotypes, but also neuroticism and cognitive ability, in mostly adult populations. Study participants were 9,247 school-aged children from three population-based cohorts of the DREAM-BIG consortium: ALSPAC (UK), The Generation R Study (Netherlands), and MAVAN (Canada). We associated each PRS with general and specific psychopathology factors, derived from a bifactor model based on self-report and parental, teacher, and observer reports. After fitting each PRS in separate models, we also tested a multi-PRS model, in which all PRSs are entered simultaneously as predictors of the general psychopathology factor.

RESULTS

Seven PRSs were associated with the general psychopathology factor after multiple testing adjustment, two with specific externalizing and five with specific internalizing psychopathology. PRSs predicted general psychopathology independently of each other, with the exception of depression and depressive symptom PRSs. Most PRSs associated with a specific psychopathology domain, were also associated with general child psychopathology.

CONCLUSIONS

The results suggest that PRSs based on current GWASs of psychiatric phenotypes tend to be associated with general psychopathology, or both general and specific psychiatric domains, but not with one specific psychopathology domain only. Furthermore, PRSs can be combined to improve predictive ability. PRS users should therefore be conscious of nonspecificity and consider using multiple PRSs simultaneously, when predicting psychiatric disorders.

Developmental Language Disorder and Psychopathology: Disentangling Shared Genetic and Environmental Influences

There is considerable variability in the extent to which young people with developmental language disorder (DLD) experience mental health difficulties. What drives these individual differences remains unclear. In the current article, data from the Twin Early Development Study were used to investigate the genetic and environmental influences on psychopathology in children and adolescents with DLD (n = 325) and those without DLD (n = 865). Trivariate models were fitted to investigate etiological influences on DLD and psychopathology, and bivariate heterogeneity and homogeneity models were fitted and compared to investigate quantitative differences in etiological influences on psychopathology between those with and without DLD. The genetic correlation between DLD and internalizing problems in childhood was significant, suggesting that their co-occurrence is due to common genetic influences. Similar, but nonsignificant effects were observed for externalizing problems. In addition, genetic influences on internalizing problems, but not externalizing problems, appeared to be higher in young people with DLD than those without DLD, suggesting that the presence of DLD may exacerbate genetic risk for internalizing problems. These findings indicate that genetic influences on internalizing problems may also confer susceptibility to DLD (or vice versa) and that DLD serves as an additional risk factor for those with a genetic predisposition for internalizing problems.

The association between body dysmorphic symptoms and suicidality among adolescents and young adults: a genetically informative study

BACKGROUND

Previous research indicates that body dysmorphic disorder (BDD) is associated with risk of suicidality. However, studies have relied on small and/or specialist samples and largely focussed on adults, despite these difficulties commonly emerging in youth. Furthermore, the aetiology of the relationship remains unknown.

METHODS

Two independent twin samples were identified through the Child and Adolescent Twin Study in Sweden, at ages 18 (N = 6027) and 24 (N = 3454). Participants completed a self-report measure of BDD symptom severity. Young people and parents completed items assessing suicidal ideation/behaviours. Logistic regression models tested the association of suicidality outcomes with: (a) probable BDD, classified using an empirically derived cut-off; and (b) continuous scores of BDD symptoms. Bivariate genetic models examined the aetiology of the association between BDD symptoms and suicidality at both ages.

RESULTS

Suicidal ideation and behaviours were common among those with probable BDD at both ages. BDD symptoms, measured continuously, were linked with all aspects of suicidality, and associations generally remained significant after adjusting for depressive and anxiety symptoms. Genetic factors accounted for most of the covariance between BDD symptoms and suicidality (72.9 and 77.7% at ages 18 and 24, respectively), but with significant non-shared environmental influences (27.1 and 22.3% at ages 18 and 24, respectively).

CONCLUSIONS

BDD symptoms are associated with a substantial risk of suicidal ideation and behaviours in late adolescence and early adulthood. This relationship is largely explained by common genetic liability, but non-shared environmental effects are also significant and could provide opportunities for prevention among those at high-risk.

Overview of CAPICE-Childhood and Adolescence Psychopathology: unravelling the complex etiology by a large Interdisciplinary Collaboration in Europe-an EU Marie Skłodowska-Curie International Training Network

The Roadmap for Mental Health and Wellbeing Research in Europe (ROAMER) identified child and adolescent mental illness as a priority area for research. CAPICE (Childhood and Adolescence Psychopathology: unravelling the complex etiology by a large Interdisciplinary Collaboration in Europe) is a European Union (EU) funded training network aimed at investigating the causes of individual differences in common childhood and adolescent psychopathology, especially depression, anxiety, and attention deficit hyperactivity disorder. CAPICE brings together eight birth and childhood cohorts as well as other cohorts from the EArly Genetics and Life course Epidemiology (EAGLE) consortium, including twin cohorts, with unique longitudinal data on environmental exposures and mental health problems, and genetic data on participants. Here we describe the objectives, summarize the methodological approaches and initial results, and present the dissemination strategy of the CAPICE network. Besides identifying genetic and epigenetic variants associated with these phenotypes, analyses have been performed to shed light on the role of genetic factors and the interplay with the environment in influencing the persistence of symptoms across the lifespan. Data harmonization and building an advanced data catalogue are also part of the work plan. Findings will be disseminated to non-academic parties, in close collaboration with the Global Alliance of Mental Illness Advocacy Networks-Europe (GAMIAN-Europe).

The Latent Structure of Child and Adolescent Psychopathology and its Association with Different Forms of Trauma and Suicidality and Self-Harm : LATENT STRUCTURE OF PSYCHOPATHOLOGY

The Hierarchical Taxonomy of Psychopathology (HiTOP) is a multidimensional and hierarchical model of the latent structure of psychopathology. While HiTOP has received much support in child/adolescent community samples, fewer studies have assessed this model in clinical samples of children/adolescents. Here, we modelled the latent structure of 45 symptoms of psychopathology from a clinical sample of children/adolescents and assessed how dimensions of psychopathology were related to specific forms of trauma and suicidality/self-harm. Clinician-derived assessments were obtained from 507 people aged 7-18 years. Confirmatory factor analysis was used to determine the optimal fitting model, and structural equation modelling was used to estimate associations with trauma exposure and suicidality/self-harm. The best fitting model(s) included five first-order factors reflecting Fear, Distress, Externalizing, Thought Disorder, and Traumatic Stress, with a higher-order general factor (p) accounting for the covariation between these factors. Unique associations were identified between specific forms of trauma and each dimension of psychopathology. p was strongly associated with suicidality/self-harm, and of the first-order factors, Distress was most strongly associated with suicidality/self-harm. Findings support the predictions of HiTOP that the latent structure of child/adolescent psychopathology can be effectively described by a multidimensional and hierarchal model. Moreover, we found tentative evidence for a unique dimension of Traumatic Stress psychopathology. Our findings also highlight the unique associations between specific forms of early life trauma and specific dimensions of psychopathology, and the importance of Distress related psychopathology for suicidality/self-harm in children and adolescents.

Genetics in the ADHD Clinic: How Can Genetic Testing Support the Current Clinical Practice?

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder with a childhood prevalence of 5%. In about two-thirds of the cases, ADHD symptoms persist into adulthood and often cause significant functional impairment. Based on the results of family and twin studies, the estimated heritability of ADHD approximates 80%, suggests a significant genetic component in the etiological background of the disorder; however, the potential genetic effects on disease risk, symptom severity, and persistence are unclear. This article provides a brief review of the genome-wide and candidate gene association studies with a focus on the clinical aspects, summarizing findings of ADHD disease risk, ADHD core symptoms as dimensional traits, and other traits frequently associated with ADHD, which may contribute to the susceptibility to other comorbid psychiatric disorders. Furthermore, neuropsychological impairment and measures from neuroimaging and electrophysiological paradigms, emerging as potential biomarkers, also provide a prominent target for molecular genetic studies, since they lie in the pathway from genes to behavior; therefore, they can contribute to the understanding of the underlying neurobiological mechanisms and the interindividual heterogeneity of clinical symptoms. Beyond the aforementioned aspects, throughout the review, we also give a brief summary of the genetic results, including polygenic risk scores that can potentially predict individual response to different treatment options and may offer a possibility for personalized treatment for the therapy of ADHD in the future.

Parenting in the Context of the Child: Genetic and Social Processes

The focus on the role of parenting in child development has a long-standing history. When measures of parenting precede changes in child development, researchers typically infer a causal role of parenting practices and attitudes on child development. However, this research is usually conducted with parents raising their own biological offspring. Such research designs cannot account for the effects of genes that are common to parents and children, nor for genetically influenced traits in children that influence how they are parented and how parenting affects them. The aim of this monograph is to provide a clearer view of parenting by synthesizing findings from the Early Growth and Development Study (EGDS). EGDS is a longitudinal study of adopted children, their birth parents, and their rearing parents studied across infancy and childhood. Families (N = 561) were recruited in the United States through adoption agencies between 2000 and 2010. Data collection began when adoptees were 9 months old (males = 57.2%; White 54.5%, Black 13.2%, Hispanic/Latinx 13.4%, Multiracial 17.8%, other 1.1%). The median child age at adoption placement was 2 days (M = 5.58, SD = 11.32). Adoptive parents were predominantly in their 30s, White, and coming from upper-middle- or upper-class backgrounds with high educational attainment (a mode at 4-year college or graduate degree). Most adoptive parents were heterosexual couples, and were married at the beginning of the project. The birth parent sample was more racially and ethnically diverse, but the majority (70%) were White. At the beginning of the study, most birth mothers and fathers were in their 20s, with a mode of educational attainment at high school degree, and few of them were married. We have been following these family members over time, assessing their genetic influences, prenatal environment, rearing environment, and child development. Controlling for effects of genes common to parents and children, we confirmed some previously reported associations between parenting, parent psychopathology, and marital adjustment in relation to child problematic and prosocial behavior. We also observed effects of children's heritable characteristics, characteristics thought to be transmitted from parent to child by genetic means, on their parents and how those effects contributed to subsequent child development. For example, we found that genetically influenced child impulsivity and social withdrawal both elicited harsh parenting, whereas a genetically influenced sunny disposition elicited parental warmth. We found numerous instances of children's genetically influenced characteristics that enhanced positive parental influences on child development or that protected them from harsh parenting. Integrating our findings, we propose a new, genetically informed process model of parenting. We posit that parents implicitly or explicitly detect genetically influenced liabilities and assets in their children. We also suggest future research into factors such as marital adjustment, that favor parents responding with appropriate protection or enhancement. Our findings illustrate a productive use of genetic information in prevention research: helping parents respond effectively to a profile of child strengths and challenges rather than using genetic information simply to identify some children unresponsive to current preventive interventions.

Validity and utility of Hierarchical Taxonomy of Psychopathology (HiTOP): III. Emotional dysfunction superspectrum

The Hierarchical Taxonomy of Psychopathology (HiTOP) is a quantitative nosological system that addresses shortcomings of traditional mental disorder diagnoses, including arbitrary boundaries between psychopathology and normality, frequent disorder co-occurrence, substantial heterogeneity within disorders, and diagnostic unreliability over time and across clinicians. This paper reviews evidence on the validity and utility of the internalizing and somatoform spectra of HiTOP, which together provide support for an emotional dysfunction superspectrum. These spectra are composed of homogeneous symptom and maladaptive trait dimensions currently subsumed within multiple diagnostic classes, including depressive, anxiety, trauma-related, eating, bipolar, and somatic symptom disorders, as well as sexual dysfunction and aspects of personality disorders. Dimensions falling within the emotional dysfunction superspectrum are broadly linked to individual differences in negative affect/neuroticism. Extensive evidence establishes that dimensions falling within the superspectrum share genetic diatheses, environmental risk factors, cognitive and affective difficulties, neural substrates and biomarkers, childhood temperamental antecedents, and treatment response. The structure of these validators mirrors the quantitative structure of the superspectrum, with some correlates more specific to internalizing or somatoform conditions, and others common to both, thereby underlining the hierarchical structure of the domain. Compared to traditional diagnoses, the internalizing and somatoform spectra demonstrated substantially improved utility: greater reliability, larger explanatory and predictive power, and greater clinical applicability. Validated measures are currently available to implement the HiTOP system in practice, which can make diagnostic classification more useful, both in research and in the clinic.

Systematic Review: Molecular Studies of Common Genetic Variation in Child and Adolescent Psychiatric Disorders

OBJECTIVE

A systematic review of studies using molecular genetics and statistical approaches to investigate the role of common genetic variation in the development, persistence, and comorbidity of childhood psychiatric traits was conducted.

METHOD

A literature review was performed using the PubMed database, following PRISMA guidelines. There were 131 studies meeting inclusion criteria, having investigated at least one type of childhood-onset or childhood-measured psychiatric disorder or trait with the aim of identifying trait-associated common genetic variants, estimating the contribution of single nucleotide polymorphisms (SNPs) to the amount of variance explained (SNP-based heritability), investigating genetic overlap between psychiatric traits, or investigating whether the stability in traits or the association with adult traits is explained by genetic factors.

RESULTS

The first robustly associated genetic variants have started to be identified for childhood psychiatric traits. There were substantial contributions of common genetic variants to many traits, with variation in single nucleotide polymorphism heritability estimates depending on age and raters. Moreover, genetic variants also appeared to explain comorbidity as well as stability across a range of psychiatric traits in childhood and across the life span.

CONCLUSION

Common genetic variation plays a substantial role in childhood psychiatric traits. Increased sample sizes will lead to increased power to identify genetic variants and to understand genetic architecture, which will ultimately be beneficial to targeted and prevention strategies. This can be achieved by harmonizing phenotype measurements, as is already proposed by large international consortia and by including the collection of genetic material in every study.

The P-factor and its genomic and neural equivalents: an integrated perspective

Different psychiatric disorders and symptoms are highly correlated in the general population. A general psychopathology factor (or "P-factor") has been proposed to efficiently describe this covariance of psychopathology. Recently, genetic and neuroimaging studies also derived general dimensions that reflect densely correlated genomic and neural effects on behaviour and psychopathology. While these three types of general dimensions show striking parallels, it is unknown how they are conceptually related. Here, we provide an overview of these three general dimensions, and suggest a unified interpretation of their nature and underlying mechanisms. We propose that the general dimensions reflect, in part, a combination of heritable 'environmental' factors, driven by a dense web of gene-environment correlations. This perspective calls for an update of the traditional endophenotype framework, and encourages methodological innovations to improve models of gene-brain-environment relationships in all their complexity. We propose concrete approaches, which by taking advantage of the richness of current large databases will help to better disentangle the complex nature of causal factors underlying psychopathology.

Modeling environment through a general exposome factor in two independent adolescent cohorts

Exposures to perinatal, familial, social, and physical environmental stimuli can have substantial effects on human development. We aimed to generate a single measure that capture's the complex network structure of the environment (ie, exposome) using multi-level data (participant's report, parent report, and geocoded measures) of environmental exposures (primarily from the psychosocial environment) in two independent adolescent cohorts: The Adolescent Brain Cognitive Development Study (ABCD Study, N = 11 235; mean age, 10.9 years; 47.7% females) and an age- and sex-matched sample from the Philadelphia Neurodevelopmental Cohort (PNC, N = 4993). We conducted a series of data-driven iterative factor analyses and bifactor modeling in the ABCD Study, reducing dimensionality from 348 variables tapping to environment to six orthogonal exposome subfactors and a general (adverse) exposome factor. The general exposome factor was associated with overall psychopathology (B = 0.28, 95% CI, 0.26-0.3) and key health-related outcomes: obesity (odds ratio [OR] , 1.4; 95% CI, 1.3-1.5) and advanced pubertal development (OR, 1.3; 95% CI, 1.2-1.5). A similar approach in PNC reduced dimensionality of environment from 29 variables to 4 exposome subfactors and a general exposome factor. PNC analyses yielded consistent associations of the general exposome factor with psychopathology (B = 0.15; 95% CI, 0.13-0.17), obesity (OR, 1.4; 95% CI, 1.3-1.6), and advanced pubertal development (OR, 1.3; 95% CI, 1-1.6). In both cohorts, inclusion of exposome factors greatly increased variance explained in overall psychopathology compared with models relying solely on demographics and parental education (from <4% to >38% in ABCD; from <4% to >18.5% in PNC). Findings suggest that a general exposome factor capturing multi-level environmental exposures can be derived and can consistently explain variance in youth's mental and general health.

The structure of dimensions of psychopathology in normative and clinical samples: Applying causal discovery to MMPI-2-RF scales to investigate clustering of psychopathology spectra and p-factors

We applied a Bayesian Constraint-based Causal Discovery method (BCCD) to examine the hierarchical structure of the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) Restructured Clinical (RC) scales. Two different general psychopathology super spectra (p-factor) scales were extracted from (1) all RC scales and (2) all RC scales except the RCd (Demoralization) scale. These p-factor scales were included in separate models to investigate the structure of dimensions of psychopathology in a normative (n = 3,242) and clinical (n = 2,466) sample, as well as the combined normative/clinical sample (N = 5,708), by applying the BCCD algorithm to obtain a data-driven reconstruction of the internal hierarchical structure of the MMPI-2-RF. Research on the underlying structure of the MMPI-2-RF has clinical relevance as well as conceptual relevance in the context of the HiTOP model. Results demonstrated that the syndromes measured with the RC-scales-in presence of a p-factor-cluster into six spectra: internalizing, disinhibited-externalizing, antagonistic-externalizing, thought disorder, detachment, and somatoform. These results may support a super spectrum construct, as it was necessary for obtaining a bottom-up reconstruction of this six-spectrum structure. We found support for superiority of a broad super spectrum with additional variance over and above demoralization, as it resulted in the clearest structure (i.e., clustering of the RC scales). Furthermore, our results indicate independent support for the bifactor structure model of psychopathology.

Polygenic scores differentially predict developmental trajectories of subtypes of social withdrawal in childhood

BACKGROUND

Children who consistently withdraw from social situations face increased risk for later socioemotional difficulties. Twin studies indicate that genetic factors substantially account for the persistence of social withdrawal over time. However, the molecular genetic etiology of chronic courses of social wariness and preference for solitude, two dimensions of social withdrawal, remains undocumented. The objectives of the present study were (a) to identify high-risk trajectories for social wariness and preference for solitude in childhood and (b) to examine whether falling on these high-risk trajectories can be predicted by specific polygenic scores for mental health traits and disorders and by a general polygenic predisposition to these traits.

METHODS

Teachers evaluated 971 genotyped children at five occasions (age 6 to 12 years) from two prospective longitudinal studies, the Quebec Newborn Twin Study and the Quebec Longitudinal Study of Child Development. Developmental trajectories for social wariness and preference for solitude were identified. We tested whether polygenic scores for attention deficit hyperactivity disorder, autism spectrum disorder, depression, loneliness, and subjective well-being, as well as a general mental health genetic risk score derived across these traits, were associated with the developmental trajectories.

RESULTS

Polygenic scores differentially predicted social wariness and preference for solitude. Only the loneliness polygenic score significantly predicted the high trajectory for social wariness. By contrast, the general mental health genetic risk score factor was associated with the trajectory depicting high-chronic preference for solitude.

CONCLUSIONS

Distinct associations were uncovered between the polygenic scores, social wariness, and preference for solitude.

The consequences of a year of the COVID-19 pandemic for the mental health of young adult twins in England and Wales

The COVID-19 pandemic has impacted all our lives, not only through the infection itself, but also through the measures taken to control the virus’s spread (e.g., lockdown). Here we investigated how the COVID-19 pandemic and unprecedented lockdown affected the mental health of young adults in England and Wales. We compared the mental health symptoms of up to 4,000 twins in their mid-twenties in 2018 prior to the COVID-19 pandemic (T1) to those in a four-wave longitudinal data collection during the pandemic in April, July, and October 2020, and in March 2021 (T2-T5). The average changes in mental health were small-to-medium and mainly occurred from 2018 (T1) to March 2020 (T2, one month following the start of lockdown; average Cohen d=0.14). Despite the expectation of catastrophic effects on the pandemic on mental health of our young adults, we did not observe trends in worsening mental health during the pandemic (T3-T5). Young people with pre-existing mental health problems were adversely affected at the beginning of the pandemic, but their increased problems largely subsided as the pandemic persisted. Twin analyses indicated that the aetiology of individual differences did not change during the lockdown. The average heritability of mental health symptoms was 33% across 5 waves of assessment, and the average genetic correlation between T1 and T2-T5 was .95, indicating that genetic effects before the pandemic (T1) are substantially correlated with genetic effects up to a year later (T2-T5). We conclude that on average the mental health of young adults in England and Wales has been remarkably resilient to the effects of the pandemic and associated lockdown.

Elucidating the Links Between Mother and Father Alcohol Use Disorder and Adolescent Externalizing Psychopathology: A Test of Transmission Specificity Within Competing Factor Structures and Genetic and Environmental Liabilities

Parental alcohol use disorder (AUD) is a substantiated risk factor for adolescent externalizing psychopathology; however, the level of specificity at which risk from parental AUD is transmitted to adolescent offspring should be interrogated further. The current study modeled competing factor structures of psychopathology in a sample of 502 adolescent twin pairs (Mage = 13.24 years) and tested associations with mother and father AUD. The bifactor model exhibited the best fit to the data when contrasted with correlated factors and general factor models. Paternal AUD predicted the externalizing and internalizing correlated factors, the adolescent P-factor but not the residual externalizing and internalizing factors, and the general factor. No significant associations with maternal AUD were noted. Lastly, the latent factors of adolescent psychopathology were all moderately heritable (h2 = 0.44-0.59) and influenced by the nonshared environment. Shared genetic factors primarily explained externalizing and internalizing covariance. Findings suggest that efforts to mitigate risk in offspring of fathers exhibiting AUD require broader approaches that address the full range of adolescent symptomology.

Commentary: Time to reconceptualize ASD? comments on Happe and Frith (2020) and Sonuga-Barke (2020)

Happe and Frith (2020) list seven changes in the concept of autism that have taken place since the 80s when autism became the focus of clinical concerns and research interests. These dramatic changes, supported by additional research results, have not convinced Sonuga-Barke (2020) that a Kuhnian revolution in psychiatric nosology may be at our front door. This commentary will discuss this conclusion, calling on ASD researchers to re-evaluate the benefits of a paradigm shift in the nosology of ASD.

Prediction Along a Developmental Perspective in Psychiatry: How Far Might We Go?

Most mental disorders originate in childhood, and once symptoms present, a variety of psychosocial and cognitive maladjustments may arise. Although early childhood problems are generally associated with later mental health impairments and psychopathology, pluripotent transdiagnostic trajectories may manifest. Possible predictors range from behavioral and neurobiological mechanisms, genetic predispositions, environmental and social factors, and psychopathological comorbidity. They may manifest in altered neurodevelopmental trajectories and need to be validated capitalizing on large-scale multi-modal epidemiological longitudinal cohorts. Moreover, clinical and etiological variability between patients with the same disorders represents a major obstacle to develop effective treatments. Hence, in order to achieve stratification of patient samples opening the avenue of adapting and optimizing treatment for the individual, there is a need to integrate data from multi-dimensionally phenotyped clinical cohorts and cross-validate them with epidemiological cohort data. In the present review, we discuss these aspects in the context of externalizing and internalizing disorders summarizing the current state of knowledge, obstacles, and pitfalls. Although a large number of studies have already increased our understanding on neuropsychobiological mechanisms of mental disorders, it became also clear that this knowledge might only be the tip of the Eisberg and that a large proportion still remains unknown. We discuss prediction strategies and how the integration of different factors and methods may provide useful contributions to research and at the same time may inform prevention and intervention.