Publikationsansicht. 22352432. On Studying Evil (2006). Kubarych,Thomas S. Abstract. Philosophy, ... more Publikationsansicht. 22352432. On Studying Evil (2006). Kubarych,Thomas S. Abstract. Philosophy, Psychiatry, & Psychology - Volume 12, Number 3, September 2005. Details der Publikation. ...
Background.Mixed anxiety–depression (MAD) has been under scrutiny to determine its potential plac... more Background.Mixed anxiety–depression (MAD) has been under scrutiny to determine its potential place in psychiatric nosology. The current study sought to investigate its prevalence, clinical characteristics, course and potential validators.Method.Restricted latent-class analyses were fit to 12-month self-reports of depression and anxiety symptom criteria in a large population-based sample of twins. Classes were examined across an array of relevant indicators (demographics, co-morbidity, adverse life events, clinical significance and twin concordance). Longitudinal analyses investigated the stability of, and transitions between, these classes for two time periods approximately 1.5 years apart.Results.In all analyses, a class exhibiting levels of MAD symptomatology distinctly above the unaffected subjects yet having low prevalence of either major depression (MD) or generalized anxiety disorder (GAD) was identified. A restricted four-class model, constraining two classes to have no prior...
Understanding genetic and environmental effects on white matter development in the first years of... more Understanding genetic and environmental effects on white matter development in the first years of life is of great interest, as it provides insights into the etiology of neurodevelopmental disorders. In this study, the genetic and environmental effects on white matter were estimated using data from 173 neonatal twin subjects. Diffusion tensor imaging scans were acquired around 40 days after birth and were non-rigidly registered to a group-specific atlas and parcellated into 98 ROIs. A model of additive genetic, and common and specific environmental variance components was used to estimate overall and regional genetic and environmental contributions to diffusion parameters of fractional anisotropy, radial diffusivity, and axial diffusivity. Correlations between the regional heritability values and diffusion parameters were also examined. Results indicate that individual differences in overall white matter microstructure, represented by the average diffusion parameters over the whole ...
The estimation of cortical thickness is in part dependent on the degree of contrast in T1 signal ... more The estimation of cortical thickness is in part dependent on the degree of contrast in T1 signal intensity between white matter and gray matter along the cortical mantle. The ratio of white matter to gray matter signal (WM/GM contrast) has been found to vary as a function of age and Alzheimer's disease status, suggesting a biological component to what might otherwise be labeled as a nuisance variable. The aim of the present study was to determine if measures of WM/GM contrast are genetically influenced, as well as the degree to which this phenotype may be related to the genetic and environment determinants of cortical thickness. Participants were 514 male twins (130 monozygotic, 97 dizygotic pairs, and 60 unpaired individuals) from the Vietnam Era Twin Study of Aging. Ages ranged from 51 to 59years. Measures of WM/GM contrast and cortical thickness were derived for 66 cortical regions of interest (ROI) using FreeSurfer-based methods. Univariate and bivariate twin analyses were ...
Ordered latent class analysis (OLCA) can be used to approximate unidimensional la-tent distributi... more Ordered latent class analysis (OLCA) can be used to approximate unidimensional la-tent distributions. The main objective of this study is to evaluate the method of OLCA in detecting non-normality of an unobserved continuous variable (i.e., a common factor) used to explain the covariation between dichotomous item-level responses. Using simulation, we compared a model in which probabilities of class membership were estimated to a restricted submodel in which class memberships were fixed to normal Gauss–Hermite quadrature values. Our results indicate that the likelihood ra-tio statistic follows a predictable chi-square distribution for a wide range of sample sizes (N = 500–12,000) and test instrument characteristics, and has reasonable power to detect non-normality in cases of moderate effect sizes. Furthermore, under situa-tions of large sample sizes, large numbers of items, or centrally located item difficul-ties, simulations suggest that it may be possible to describe the shape of l...
Background The aggregation of neurocognitive deficits among the non-psychotic first-degree relati... more Background The aggregation of neurocognitive deficits among the non-psychotic first-degree relatives of adult- and childhood-onset schizophrenia patients suggests that there may be a common etiology for these deficits in childhood- and adult-onset illness. However, there is considerable heterogeneity in the presentation of neurobiological abnormalities, and whether there are differences in the extent of familial transmission for specific domains of cognitive function has not been systematically addressed. Methods We employed variance components analysis, as implemented in SOLAR-Eclipse, to evaluate the evidence of familial transmission for empirically derived composite scores representing attention, working memory, verbal learning, verbal retention, and memory for faces. We contrast estimates for adult- and childhood-onset schizophrenia families and matched community control pedigrees, and compare our findings to previous reports based on analogous neurocognitive assessments. Result...
Publikationsansicht. 22352431. Self-Deception and Peck's Analysis of Evil (2006).Kubarych, T... more Publikationsansicht. 22352431. Self-Deception and Peck's Analysis of Evil (2006).Kubarych, Thomas S. Abstract. Philosophy, Psychiatry, & Psychology - Volume 12, Number 3, September 2005. Details der Publikation. ...
Publikationsansicht. 22352432. On Studying Evil (2006). Kubarych,Thomas S. Abstract. Philosophy, ... more Publikationsansicht. 22352432. On Studying Evil (2006). Kubarych,Thomas S. Abstract. Philosophy, Psychiatry, & Psychology - Volume 12, Number 3, September 2005. Details der Publikation. ...
Background.Mixed anxiety–depression (MAD) has been under scrutiny to determine its potential plac... more Background.Mixed anxiety–depression (MAD) has been under scrutiny to determine its potential place in psychiatric nosology. The current study sought to investigate its prevalence, clinical characteristics, course and potential validators.Method.Restricted latent-class analyses were fit to 12-month self-reports of depression and anxiety symptom criteria in a large population-based sample of twins. Classes were examined across an array of relevant indicators (demographics, co-morbidity, adverse life events, clinical significance and twin concordance). Longitudinal analyses investigated the stability of, and transitions between, these classes for two time periods approximately 1.5 years apart.Results.In all analyses, a class exhibiting levels of MAD symptomatology distinctly above the unaffected subjects yet having low prevalence of either major depression (MD) or generalized anxiety disorder (GAD) was identified. A restricted four-class model, constraining two classes to have no prior...
Understanding genetic and environmental effects on white matter development in the first years of... more Understanding genetic and environmental effects on white matter development in the first years of life is of great interest, as it provides insights into the etiology of neurodevelopmental disorders. In this study, the genetic and environmental effects on white matter were estimated using data from 173 neonatal twin subjects. Diffusion tensor imaging scans were acquired around 40 days after birth and were non-rigidly registered to a group-specific atlas and parcellated into 98 ROIs. A model of additive genetic, and common and specific environmental variance components was used to estimate overall and regional genetic and environmental contributions to diffusion parameters of fractional anisotropy, radial diffusivity, and axial diffusivity. Correlations between the regional heritability values and diffusion parameters were also examined. Results indicate that individual differences in overall white matter microstructure, represented by the average diffusion parameters over the whole ...
The estimation of cortical thickness is in part dependent on the degree of contrast in T1 signal ... more The estimation of cortical thickness is in part dependent on the degree of contrast in T1 signal intensity between white matter and gray matter along the cortical mantle. The ratio of white matter to gray matter signal (WM/GM contrast) has been found to vary as a function of age and Alzheimer's disease status, suggesting a biological component to what might otherwise be labeled as a nuisance variable. The aim of the present study was to determine if measures of WM/GM contrast are genetically influenced, as well as the degree to which this phenotype may be related to the genetic and environment determinants of cortical thickness. Participants were 514 male twins (130 monozygotic, 97 dizygotic pairs, and 60 unpaired individuals) from the Vietnam Era Twin Study of Aging. Ages ranged from 51 to 59years. Measures of WM/GM contrast and cortical thickness were derived for 66 cortical regions of interest (ROI) using FreeSurfer-based methods. Univariate and bivariate twin analyses were ...
Ordered latent class analysis (OLCA) can be used to approximate unidimensional la-tent distributi... more Ordered latent class analysis (OLCA) can be used to approximate unidimensional la-tent distributions. The main objective of this study is to evaluate the method of OLCA in detecting non-normality of an unobserved continuous variable (i.e., a common factor) used to explain the covariation between dichotomous item-level responses. Using simulation, we compared a model in which probabilities of class membership were estimated to a restricted submodel in which class memberships were fixed to normal Gauss–Hermite quadrature values. Our results indicate that the likelihood ra-tio statistic follows a predictable chi-square distribution for a wide range of sample sizes (N = 500–12,000) and test instrument characteristics, and has reasonable power to detect non-normality in cases of moderate effect sizes. Furthermore, under situa-tions of large sample sizes, large numbers of items, or centrally located item difficul-ties, simulations suggest that it may be possible to describe the shape of l...
Background The aggregation of neurocognitive deficits among the non-psychotic first-degree relati... more Background The aggregation of neurocognitive deficits among the non-psychotic first-degree relatives of adult- and childhood-onset schizophrenia patients suggests that there may be a common etiology for these deficits in childhood- and adult-onset illness. However, there is considerable heterogeneity in the presentation of neurobiological abnormalities, and whether there are differences in the extent of familial transmission for specific domains of cognitive function has not been systematically addressed. Methods We employed variance components analysis, as implemented in SOLAR-Eclipse, to evaluate the evidence of familial transmission for empirically derived composite scores representing attention, working memory, verbal learning, verbal retention, and memory for faces. We contrast estimates for adult- and childhood-onset schizophrenia families and matched community control pedigrees, and compare our findings to previous reports based on analogous neurocognitive assessments. Result...
Publikationsansicht. 22352431. Self-Deception and Peck's Analysis of Evil (2006).Kubarych, T... more Publikationsansicht. 22352431. Self-Deception and Peck's Analysis of Evil (2006).Kubarych, Thomas S. Abstract. Philosophy, Psychiatry, & Psychology - Volume 12, Number 3, September 2005. Details der Publikation. ...
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