A quantitative genetic analysis of schizotypal personality traits

2003 ◽  
Vol 33 (5) ◽  
pp. 803-816 ◽  
Author(s):  
Y. M. LINNEY ◽  
R. M. MURRAY ◽  
E. R. PETERS ◽  
A. M. MacDONALD ◽  
F. RIJSDIJK ◽  
...  
Keyword(s):  
Structural Equation ◽  
Model Fitting ◽  
Twin Studies ◽  
Equation Model ◽  
Common Pathway ◽  
Schizotypal Personality ◽  
Quantitative Genetic ◽  
Best Fitting ◽  
Limited Power ◽  
Fitting Model

Background. Previous twin studies investigating the heritability of schizotypy have often had limited power and have failed to measure the disorganization/social anxiety component.Method. Seven hundred and thirty-three female twin pairs, drawn from the Institute of Psychiatry Volunteer Twin Register, completed the Oxford–Liverpool Inventory of Feelings and Experiences and the Peters et al. Delusions Inventory. Structural equation modelling was carried out on scores for MZ and DZ twin pairs.Results. The best fitting models for all scales comprised additive genetic and unique environmental effects. Heritability was estimated at approximately 50% for most scales, although it was lower at 37% for the PDI scale. Multivariate structural equation model fitting revealed a best-fitting model in which additive genetic and unique environmental influences act through a single common pathway for Cognitive Disorganization, Unusual Experiences and the PDI, and through a separate common pathway for Cognitive Disorganization and Introvertive Anhedonia.Conclusions. The various components of schizotypy are moderately heritable. Multivariate model fitting indicates that at least two latent factor structures are required to account for the covariation between the various components of schizotypy. The positive and negative components of schizotypy are relatively genetically independent, although each in turn may be related to Cognitive Disorganization.

The Heritability of CHD Mortality in Danish Twins After Controlling for Smoking and BMI

2005 ◽  
Vol 8 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Andreas Wienke ◽  
Anne M. Herskind ◽  
Kaare Christensen ◽  
Axel Skytthe ◽  
Anatoli I. Yashin
Keyword(s):  
Environmental Factors ◽  
Structural Equation ◽  
Equation Model ◽  
Mortality Data ◽  
Best Fitting ◽  
Genetic And Environmental Factors ◽  
Individual Frailty ◽  
Fitting Model ◽  
Model Approach

AbstractCause-specific mortality data on Danish monozygotic and dizygotic twins are used to analyze heritability estimates of susceptibility to coronary heart disease (CHD) after controlling for smoking and Body Mass Index (BMI). The sample includes 1209 like-sexed twin pairs born between 1890 and 1920, where both individuals were still alive in 1966. The participants completed a questionnaire in 1966 which included questions on smoking, height and weight. The analysis was conducted with both sexes pooled due to the relatively small number of twin pairs. Follow-up was conducted from January 1, 1966 to December 31, 1993. The correlated gammafrailty model with observed covariates was used for the genetic analysis of frailty to account for censoring and truncation in the lifetime data. During the follow-up, 1437 deaths occurred, including 435 deaths due to CHD. Proportions of variance of frailty attributable to genetic and environmental factors were analyzed using the structural equation model approach. Different standard biometric models are fitted to the data to evaluate the magnitude and nature of genetic and environmental factors on mortality. Using the best-fitting model without covariates, heritability of frailty to CHD was found to be 0.45 (0.11). This result changes only slightly to 0.55 (0.13) in a DE model after controlling for smoking and BMI. This analysis underlines the existence of a substantial genetic influence on individual frailty associated with mortality caused by CHD.

Parental treatment and the equal environment assumption in twin studies of psychiatric illness

1994 ◽  
Vol 24 (3) ◽  
pp. 579-590 ◽  
Author(s):  
K. S. Kendler ◽  
M. C. Neale ◽  
R. C. Kessler ◽  
A. C. Heath ◽  
L. J. Eaves
Keyword(s):  
Psychiatric Disorders ◽  
Structural Equation ◽  
Statistical Power ◽  
Model Fitting ◽  
Twin Studies ◽  
Population Based ◽  
Equation Model ◽  
Parental Treatment ◽  
Mz Twins ◽  
Twin Resemblance

SynopsisThe validity of the twin method depends on the equal environment assumption (EEA) – that monozygotic (MZ) and dizygotic (DZ) twins are equally correlated in their exposure to environmental factors of aetiological importance for the trait under study. Parents may treat MZ twins more similarly than DZ twins thereby potentially violating the EEA. We tested this hypothesis for four common psychiatric disorders (major depression, generalized anxiety disorder, phobia, and alcoholism) in a population-based sample of female–female twin pairs where analyses indicate sufficient statistical power meaningfully to test the EEA. Mother's and father's beliefs about their twins' zygosity disagreed with assigned zygosity in approximately 20% of cases, often because of what they were told about their twins' zygosity at their birth. By structural equation model-fitting, we found no evidence that mother's or father's perceived zygosity influenced twin resemblance for any of the disorders. Compared to parents of DZ twins, parents of MZ twins were more likely to report that, in rearing their twins, they emphasized their similarities more than their differences. However, by model-fitting, mothers' and fathers' approach to raising twins had no significant influence on twin resemblance for the four examined psychiatric disorders. These results suggest that the differential treatment of MZ and DZ twins by their parents is unlikely to represent a significant bias in twin studies of these major psychiatric disorders.

Modelling Museum Visitors’ Perception and Experience of Authenticity: Examining Heterogeneity with a Finite Mixture Model

2021 ◽  
Vol 56 ◽  
pp. 0-0
Author(s):  
Claudia Bauer-Krösbacher ◽  
Josef Mazanec
Keyword(s):  
Latent Variable ◽  
Structural Equation ◽  
Latent Class ◽  
Structural Model ◽  
Unobserved Heterogeneity ◽  
Model Fitting ◽  
Equation Model ◽  
Finite Mixture ◽  
Museum Visitors ◽  
Specific Strength

Purpose. In this study, the authors explore the role of museum visitors’ perceptions and experiences of authenticity. They introduce several variants of authenticity experience and analyse how they are intertwined and feed visitor satisfaction. Method. The authors apply a multi-step model fitting and validation procedure including inferred causation methods and finite mixture modelling to verify whether the visitors’ perceptions of authenticity are subject to unobserved heterogeneity. They elaborate an Authenticity Model that demonstrates out-of-sample validity and generalisability by being exposed to new data for another cultural attraction in another city. Then, they address the heterogeneity hypothesis and evaluate it for the case study with the larger sample. Findings. In both application cases, the Sisi museum in Vienna and the Guinness Storehouse in Dublin, the empirical results support the assumed cause-effect sequence, translating high quality information display—from traditional and multimedia sources—into Perceived Authenticity and its experiential consequences such as Depth and Satisfaction. Accounting for unobserved heterogeneity detects three latent classes with segment-specific strength of relationships within the structural model. Research and conclusions limitations. The combined latent-class, structural-equation model needs validation with another sample that would have to be larger than the available Guinness database. Future studies will have to complement the purely data-driven search for heterogeneity with theory-guided reasoning about potential causes of diversity in the strength of the structural relationships. Practical implications. Cultural heritage sites are among the attractions most typical of city tourism. History tends to materialise in the artefacts accumulated by the population among the urban agglomerations, and museums are the natural places for preserving exhibits of cultural value. Authenticity must be considered an important quality assessment criterion for many visitors, whereby, the distinction between object authenticity and existential authenticity is crucial. Originality. In addition to making substantive contributions to authenticity theory, the authors also extend previous research in terms of methodological effort. Authenticity research, so far, has neither exploited inferred causation methods nor combined latent variable modelling with detecting unobserved heterogeneity. Type of paper: Research article.

scholarly journals Heritability of Schneider's first-rank symptoms

2002 ◽  
Vol 180 (1) ◽  
pp. 35-38 ◽  
Author(s):  
Alastair G. Cardno ◽  
Pak C. Sham ◽  
Anne E. Farmer ◽  
Robin M. Murray ◽  
Peter McGuffin
Keyword(s):  
Model Fitting ◽  
Heritability Estimate ◽  
Best Fitting ◽  
Same Gender ◽  
First Rank Symptoms ◽  
Fitting Model ◽  
Biometric Model

BackgroundSchneider's first-rank symptoms are given particular weight when making a diagnosis of schizophrenia, but the nuclear syndrome, characterised by one or more first-rank symptoms, has been found previously to have no heritability.AimsTo estimate the heritability of the nuclear syndrome.MethodA total of 224 twin pairs (106 monozygotic, 118 same-gender dizygotic) were ascertained from the Maudsley Twin Register in London via probands with any psychosis. Lifetime-ever first-rank symptoms were rated using the OPCRIT checklist. Probandwise concordance rates were calculated for the nuclear syndrome and a heritability estimate was derived from biometric model fitting.ResultsProbandwise concordance rates were 13/49 (26.5%) for monozygotic and 0/45 to 2/46 (0.0–4.3%) for dizygotic pairs. The heritability estimate for the best-fitting model was 71% (95% CI 57–82).ConclusionsThese results indicate that the nuclear syndrome shows substantial heritability, although this is slightly lower than that for schizophrenia as defined by the DSM and ICD systems.

Bystander Intervention in Bullying: Role of Social Skills and Gender

2017 ◽  
Vol 39 (2) ◽  
pp. 141-166 ◽  
Author(s):  
Lyndsay N. Jenkins ◽  
Amanda B. Nickerson
Keyword(s):  
Social Skills ◽  
Structural Equation ◽  
Equation Model ◽  
Bystander Intervention ◽  
Intervention Model ◽  
Know How ◽  
Eighth Grade Students ◽  
Best Fitting ◽  
And Gender

The Bystander Intervention Model proposed by social psychologists Latané and Darley has been used to examine the actions of peer bystanders in bullying. The five-stage model consists of notice the event, interpret event as an emergency, accept responsibility for intervening, know how to intervene, and implement intervention decisions. The current study examined associations among gender, social skills, and the bystander intervention model among 299 sixth- to eighth-grade students. Analyses revealed that girls reported significantly greater cooperation and empathy, and noticed bullying events, interpreted them as an emergency, and intervened more often than boys. The best fitting structural equation model included both empathy and cooperation, with significant positive path coefficients between empathy and bystander intervention. Students with greater empathy were more likely to engage with each step of the model, except noticing the event. Assertiveness was positively associated and cooperation was negatively associated with greater knowledge of how to intervene.

Feeling of Cold Hands and Feet is a Highly Heritable Phenotype

2012 ◽  
Vol 15 (2) ◽  
pp. 166-169 ◽  
Author(s):  
Yoon-Mi Hur ◽  
Jeong-Ho Chae ◽  
Ki Wha Chung ◽  
Jung Jin Kim ◽  
Hoe-Uk Jeong ◽  
...  
Keyword(s):  
Sex Differences ◽  
Measurement Error ◽  
General Population ◽  
Environmental Influences ◽  
Model Fitting ◽  
Environmental Variance ◽  
Best Fitting ◽  
Heritable Phenotype ◽  
Hands And Feet ◽  
Fitting Model

The prevalence of the feeling of cold hands and feet (FCHF) is high in the general population but the etiology of FCHF is largely unknown. The aim of the present study was to explore whether the FCHF is heritable. Eight hundred and ninety-four pairs of twins completed a question about FCHF. Tetrachoric correlations for FCHF were .58, .29, .67, .52, and .04 for monozygotic male, dizygotic male, monozygotic female, and dizygotic female twins, respectively. Model-fitting analyses suggested that in the best fitting model, additive genetic and nonshared environmental variance including measurement error were 64% (95% CI: 55%-72%) and 36% (28%-45%), respectively. Sex differences in genetic and environmental influences were not significant.

Heritability and GWAS Analyses of Acne in Australian Adolescent Twins

2017 ◽  
Vol 20 (6) ◽  
pp. 541-549 ◽  
Author(s):  
Angela Mina-Vargas ◽  
Lucía Colodro-Conde ◽  
Katrina Grasby ◽  
Gu Zhu ◽  
Scott Gordon ◽  
...  
Keyword(s):  
Structural Equation ◽  
Genome Wide Association Study ◽  
Acne Vulgaris ◽  
Monozygotic Twins ◽  
Twin Studies ◽  
Equation Model ◽  
Genome Wide ◽  
A Genome ◽  
Parsimonious Model ◽  
Three Body

Acne vulgaris is a skin disease with a multifactorial and complex pathology. While several twin studies have estimated that acne has a heritability of up to 80%, the genomic elements responsible for the origin and pathology of acne are still undiscovered. Here we performed a twin-based structural equation model, using available data on acne severity for an Australian sample of 4,491 twins and their siblings aged from 10 to 24. This study extends by a factor of 3 an earlier analysis of the genetic factors of acne. Acne severity was rated by nurses on a 4-point scale (1 = absent to 4 = severe) on up to three body sites (face, back, chest) and on up to three occasions (age 12, 14, and 16). The phenotype that we analyzed was the most severe rating at any site or age. The polychoric correlation for monozygotic twins was higher (rMZ = 0.86, 95% CI [0.81, 0.90]) than for dizygotic twins (rDZ = 0.42, 95% CI [0.35, 0.47]). A model that includes additive genetic effects and unique environmental effects was the most parsimonious model to explain the genetic variance of acne severity, and the estimated heritability was 0.85 (95% CI [0.82, 0.87]). We then conducted a genome-wide analysis including an additional 271 siblings — for a total of 4,762 individuals. A genome-wide association study (GWAS) scan did not detect loci associated with the severity of acne at the threshold of 5E-08 but suggestive association was found for three SNPs: rs10515088 locus 5q13.1 (p = 3.9E-07), rs12738078 locus 1p35.5 (p = 6.7E-07), and rs117943429 locus 18q21.2 (p = 9.1E-07). The 5q13.1 locus is close to PIK3R1, a gene that has a potential regulatory effect on sebocyte differentiation.

scholarly journals Genetic and Environmental Contributions to Variance in Age at First Sexual Intercourse

1997 ◽  
Vol 8 (3) ◽  
pp. 211-216 ◽  
Author(s):  
M.P. Dunne ◽  
N.G. Martin ◽  
D.J. Statham ◽  
W.S. Slutske ◽  
S.H. Dinwiddie ◽  
...  
Keyword(s):  
Sexual Intercourse ◽  
Structural Equation ◽  
Age At Onset ◽  
Model Fitting ◽  
Monozygotic Twins ◽  
Equation Model ◽  
Semistructured Interview ◽  
First Sexual Intercourse ◽  
Genetic And Environmental Factors ◽  
Age Range

Little is known about the relative importance of genetic and environmental factors as determinants of age at first sexual intercourse In this study, subjects were 5,080 individuals from the Australian Twin Registry (3,310 females, I 770 males, age range 27-70 years, median 40 years) who completed a semistructured interview by telephone in 1992-1993 Self-reported age at first intercourse correlated higher for identical (monozygotic) twins than for nonidentical (dizygotic) twins Structural equation model fitting found that the genetic contribution to variance was considerably greater among twins aged 40 years or less (72% for males and 49% for females) than for those aged from 41 to 70 years (0% for males and 32% for females) Among the older cohort, there was evidence that somewhat different aspects of the shared social environment influenced age at onset in males and females In a more laissez-faire social climate in recent decades, it is likely that biological and psychological characteristics that are partly under genetic control significantly influence the age at which a person commences sexual activity

scholarly journals Asteroseismology of the DAV star R808

2020 ◽  
Vol 500 (4) ◽  
pp. 4703-4709
Author(s):  
Y H Chen ◽  
H Shu
Keyword(s):  
Coulomb Potential ◽  
Model Fitting ◽  
Potential Effect ◽  
Data Set ◽  
Trapped Mode ◽  
Star Models ◽  
Diffusion Scheme ◽  
Best Fitting ◽  
Screened Coulomb Potential ◽  
Fitting Model

ABSTRACT The DAV star R808 was observed by 13 different telescopes for more than 170 h in 2009 April on the WET run XCOV26. 25 independent pulsation frequencies were identified by this data set. We assumed 19 m = 0 modes and performed an asteroseismological study on those 19 modes. We evolve grids of DAV star models by wdec adopting the element diffusion scheme with pure and screened Coulomb potential effect. The core compositions are from white dwarf models evolved by mesa, which are thermal nuclear burning results. Our best-fitting model is from the screened Coulomb potential scenario, which has parameters of log(MHe/M*) = −2.4, log(MH/M*) = −5.2, Teff = 11100 K, M* = 0.710 M⊙, logg = 8.194, and σRMS = 2.86 s. The value of σRMS is the smallest among the four existing asteroseismological work. The average period spacing is 46.299 s for l = 1 modes and 25.647 s for l = 2 modes. The other six observed modes can be fitted by $m\, \ne$ 0 components of some modes for our best-fitting model. Fitting the 25 observed modes, we obtain a σRMS value of 2.59 s. Considering the period spacings, we also assume, that at least in one case, we detect an l = 2 trapped mode.

Sign in / Sign up

Export Citation Format

Share Document