Neuroticism's prospective association with mental disorders halves after adjustment for baseline symptoms and psychiatric history, but the adjusted association hardly decays with time: a meta-analysis on 59 longitudinal/prospective studies with 443 313 participants

Spatial and temporal expression patterns of genes around nine neuroticism-associated loci

Neuroticism is a high-order personality trait. Individuals with higher neuroticism have increased risks of various psychiatric disorders and physical health outcomes. Neuroticism is related to physiological differences in the brain. A recent genome-wide association study identified nine distinct genomic loci that contribute to neuroticism. Brain development and function depend on the precise regulation of gene expression, which is differentially regulated across brain regions and developmental stages. Using multiple publicly available human post-mortem databases, we investigated, in brain and non-brain tissues and across several developmental life stages, the spatial and temporal expression patterns of genes arising from nine neuroticism-associated loci. Functional gene-network analysis for neuroticism-associated genes was performed. The spatial expression analysis revealed that the nearest genes (GRIK3, SRP9, KLHL2, PTPRD, ELAVL2, CRHR1 and CELF4) from index single-nucleotide polymorphisms (SNPs) at the nine loci were intensively enriched in the brain compared with their representation in non-brain tissues (p<1.56×10^-3). The nearest genes associated with the glutamate receptor activity network consisted mainly of GRIK3 (FDR q=4.25×10^-2). The temporal expression analysis revealed that the neuroticism-associated genes were divided into three expression patterns: KLHL2, CELF4 and CRHR1 were preferentially expressed during postnatal stages; PTPRD, ELAVL2 and MFHAS1 were expressed during prenatal stages; and the other three genes were not expressed during specific life stages. These findings suggest that the glutamate network might be a target for investigating the neurobiological mechanisms underlying susceptibilities to higher neuroticism and several psychiatric disorders and that neuroticism is mediated by genes specifically expressed in the brain during several developmental stages.

Three-way Interaction of Neuroticism, Extraversion, and Conscientiousness in the Internalizing Disorders: Evidence of Disorder Specificity in a Psychiatric Sample

It is well-established that neuroticism, extraversion, and conscientiousness are individually associated with internalizing disorders, but research suggests that these main effects may be qualified by a three-way interaction when predicting depression. The current study was the first to examine this three-way interaction in a psychiatric sample (N=463) with a range of internalizing symptoms as the outcomes. Using two omnibus personality inventories and a diagnostic interview, the expected three-way interaction emerged most consistently for symptoms of major depression, and there was also evidence of synergistic effects for post-traumatic stress disorder and generalized anxiety disorder. Findings indicate that, even in a clinically-distressed and currently-disordered sample, high levels of extraversion and conscientiousness protect against distress disorders for those with high levels of neuroticism.

A hierarchical causal taxonomy of psychopathology across the life span

We propose a taxonomy of psychopathology based on patterns of shared causal influences identified in a review of multivariate behavior genetic studies that distinguish genetic and environmental influences that are either common to multiple dimensions of psychopathology or unique to each dimension. At the phenotypic level, first-order dimensions are defined by correlations among symptoms; correlations among first-order dimensions similarly define higher-order domains (e.g., internalizing or externalizing psychopathology). We hypothesize that the robust phenotypic correlations among first-order dimensions reflect a hierarchy of increasingly specific etiologic influences. Some nonspecific etiologic factors increase risk for all first-order dimensions of psychopathology to varying degrees through a general factor of psychopathology. Other nonspecific etiologic factors increase risk only for all first-order dimensions within a more specific higher-order domain. Furthermore, each first-order dimension has its own unique causal influences. Genetic and environmental influences common to family members tend to be nonspecific, whereas environmental influences unique to each individual are more dimension-specific. We posit that these causal influences on psychopathology are moderated by sex and developmental processes. This causal taxonomy also provides a novel framework for understanding the heterogeneity of each first-order dimension: Different persons exhibiting similar symptoms may be influenced by different combinations of etiologic influences from each of the 3 levels of the etiologic hierarchy. Furthermore, we relate the proposed causal taxonomy to transdimensional psychobiological processes, which also impact the heterogeneity of each psychopathology dimension. This causal taxonomy implies the need for changes in strategies for studying the etiology, psychobiology, prevention, and treatment of psychopathology. (PsycINFO Database Record

Why Does Frustration Predict Psychopathology? Multiple Prospective Pathways over Adolescence: A Trails Study

Adolescents’ temperamental frustration is a developmental precursor of adult neuroticism and psychopathology. Because the mechanisms that underlie the prospective association between adolescents’ high frustration and psychopathology (internalizing/externalizing) have not been studied extensively, we quantified three pathways: stress generation [mediation via selection/evocation of stressful life events (SLEs)], cross–sectional frustration–psychopathology overlap (‘carry–over’/common causes), and a direct (non–mediated) vulnerability effect of frustration, including moderation of SLE impact. Frustration and psychopathology were assessed at age 16 with the Early Adolescent Temperament Questionnaire and the Youth Self–Report. No gender differences in frustration were observed. At age 19, psychopathology was reassessed by using the Adult Self–Report, while occurrence of endogenous (self–generated) and exogenous (not self–generated) SLEs during the interval (ages 16–19) were ascertained with the Life Stress Interview, an investigator–based contextual–stressfulness rating procedure (N = 957). Half of the prospective effect of frustration on psychopathology was explained by baseline overlap, including effects of ‘carry–over’ and common causes, about 5% reflected stress generation (a ‘vicious’ cycle with the environment adolescents navigate and shape), and 45% reflected unmediated association: a direct vulnerability effect including stress sensitivity or moderation of SLE impact. After adjustment for their overlap, frustration predicted the development of externalizing but not internalizing symptoms. Copyright © 2016 European Association of Personality Psychology

Personality, Psychopathology, and Psychotherapy: A Pre-specified Analysis Protocol for Confirmatory Research on Personality-Psychopathology Associations in Psychotherapy Outpatients

The role of personality trait variation in psychopathology and its influence on the outcome of psychotherapy is a burgeoning field. However, thus far most findings were based on controlled clinical trials that may only poorly represent real-world clinical settings due to highly selective samples mostly restricted to patients with major depression undergoing antidepressive medication. Focusing on personality and psychopathology in a representative naturalistic sample of psychotherapy patients is therefore worthwhile. Moreover, up to date hardly any confirmatory research has been conducted in this field. Strictly confirmatory research implies two major requirements: firstly, specific hypotheses, including expected effect sizes and statistical approaches to data analysis, must be detailed prior to inspection of the data, and secondly, corresponding protocols have to be published online and freely available. Here, we introduce a longitudinal naturalistic study aimed at examining, firstly, the prospective impact of baseline personality traits on the outcome of psychotherapy over a 6-month observation period; secondly, the stability and change in personality traits over time; thirdly, the association between longitudinal change in psychopathology and personality; fourthly, the agreement between self-reports and informant rating of personality; and fifthly, the predictive validity of personality self-reports compared to corresponding informant ratings. For it, we comprehensively state a priori hypotheses, predict the expected effect sizes and detail the statistical analyses that we intend to conduct to test these predictions. Such a stringent confirmatory design increases the transparency and objectivity of psychopathological research, which is necessary to reduce the rate of false-positive findings and to increase the yield of scientific research.