The relation between normative rituals/routines and obsessive-compulsive symptoms at a young age:A systematic review

Objective One of the most challenging issues in the pediatric obsessive–compulsive (OC) disorder field is to differentiate pathological OC symptoms from the phenotypically similar normative rituals/routines that characterize normal childhood development. Given their similarities, it can be questioned whether both constructs reflect two qualitatively distinct behavioral expressions of different etiological factors or rather reflect two diverse manifestations of one single continuum (cfr. the continuity hypothesis). Method This paper aims to improve our understanding of the relation between normative childhood rituals/routines and OC symptoms in two ways. First, the continuity hypothesis was investigated by systematically reviewing current evidence on this association, using various databases (Web of Science Core Collection, MEDLINE/PubMed, and SciELO Citation Index) from 1950 until February 1, 2019 (registration number: CRD42019121293). Second, based on this systematic review, an integrative conceptual model was developed describing this relation from different perspectives on sources of influence. Results The literature search initially revealed 2122 hits, with 114 full-texts being assessed for eligibility. After applying several selection criteria, 18 studies were included in the review. The results generally support the continuity hypothesis and reveal important etiological factors at different levels of behavioral analysis, including the phenotypic (anxiety), neurobiological and genetic level. Also age and the presence of other disorders appeared to be important factors in evaluating the level of normality. Conclusion We provide a conceptual framework to inform future research aimed at improving the understanding of the relationship between normative rituals/routines and pathological OC symptoms. Conceptual implications are discussed and clinical recommendations are given to improve early identification and differentiation

The genetic architecture of neuroticism in 3301 Dutch adolescent twins as a function of age and sex: a study from the Dutch Twin Register

The objective of this study was to estimate the magnitude of genetic and environmental influences to variation in adolescent neuroticism as a function of age and sex. Neuroticism was assessed using the Amsterdamse Biografische Vragenlijst (ABV): a self-report personality instrument similar in content to the Eysenck Personality Questionnaire. Genetic modeling procedures, including age as modifier, were fitted to the total sample of 3301 Dutch adolescent twins aged 12 to 17 years (mean age 15.5). Significant influences of additive genetic factors (.59, 95% confidence intervals [CI] .54–.63) and unshared environmental factors (.41, 95% CI .37–.45) were found. Our data did not support a role of shared environment. Results showed that different genes may influence variation in neuroticism between girls and boys. No interaction was found between the variance components and age. Results generally support prior findings in adults and young children that neuroticism is influenced principally by additive genetic and unique environmental factors. The magnitude of the genetic component appears higher in the present sample of adolescents than in most studies of adults. The present study suggests that, in adolescence, different genes are expressed in boys and girls

Latent class analysis of the Child Behavior Checklist Obsessive-Compulsive Scale

The Obsessive-Compulsive Scale (OCS) of the Child Behavior Checklist (CBCL) predicts obsessive-compulsive disorder and is highly heritable. Latent class analysis (LCA) of the OCS was used to identify profiles within this 8-item scale and to examine heritability of those profiles. The LCA was performed on maternal CBCL reports of their 6- to 18-year-old children from 2 US nationally representative samples from 1989 (n = 2475, 50% male) and 1999 (n = 2029, 53% male) and from Dutch twins in the Netherlands Twin Registry at ages 7 (n = 10 194, 49.3% male), 10 (n = 6448, 48.1% male), and 12 (n = 3674, 48.6% male) years. The heritability of the resultant classes was estimated using odds ratios of twin membership across classes. A 4-class solution fitted all samples best. The resulting classes were a "No or Few Symptoms" class, a "Worries and Has to Be Perfect" class, a "Thought Problems" class, and an "OCS" class. Within-class odds ratios were higher than across-class odds ratios and were higher for monozygotic than dizygotic twins. We conclude that LCA identifies an OCS class and that class is highly heritable using across-twin comparisons. © 2009 Elsevier Inc. All rights reserved

Host Sexual Dimorphism and Parasite Adaptation

Disease expression and prevalence often vary in the different sexes of the host. This is typically attributed to innate differences of the two sexes but specific adaptations by the parasite to one or other host sex may also contribute to these observations

Meta-analysis of genome-wide association studies for extraversion:Findings from the Genetics of Personality Consortium

Extraversion is a relatively stable and heritable personality trait associated with numerous psychosocial, lifestyle and health outcomes. Despite its substantial heritability, no genetic variants have been detected in previous genome-wide association (GWA) studies, which may be due to relatively small sample sizes of those studies. Here, we report on a large meta-analysis of GWA studies for extraversion in 63,030 subjects in 29 cohorts. Extraversion item data from multiple personality inventories were harmonized across inventories and cohorts. No genome-wide significant associations were found at the single nucleotide polymorphism (SNP) level but there was one significant hit at the gene level for a long non-coding RNA site (LOC101928162). Genome-wide complex trait analysis in two large cohorts showed that the additive variance explained by common SNPs was not significantly different from zero, but polygenic risk scores, weighted using linkage information, significantly predicted extraversion scores in an independent cohort. These results show that extraversion is a highly polygenic personality trait, with an architecture possibly different from other complex human traits, including other personality traits. Future studies are required to further determine which genetic variants, by what modes of gene action, constitute the heritable nature of extraversion