Unstable maternal environment, separation anxiety, and heightened CO2 sensitivity induced by gene-by-environment interplay.

Background: In man, many different events implying childhood separation from caregivers/unstable parental environment are associated with heightened risk for panic disorder in adulthood. Twin data show that the occurrence of such events in childhood contributes to explaining the covariation between separation anxiety disorder, panic, and the related psychobiological trait of CO(2) hypersensitivity. We hypothesized that early interference with infant-mother interaction could moderate the interspecific trait of response to CO(2) through genetic control of sensitivity to the environment.

Gene-environment interactions in panic disorder and CO₂ sensitivity: Effects of events occurring early in life.

Heterogeneous life events (LE) precede the onset of-and potentially increase the susceptibility to-panic disorder (PD). It remains unknown whether LE can act as moderators in the context of gene-by-environment interactions (G×E) that alter the susceptibility to PD and the related trait of CO₂ sensitivity, nor it is known whether such moderation may depend on occurrence of events at different epochs in life. In 712 general population twins we analyzed by Maximum Likelihood analyses of ordinal data whether life (major- and stressful) events moderate the genetic risk for PD and CO₂ sensitivity, as indexed by the 35% CO₂ /65% O₂ challenge.

A genetically informed study of the covariation between the CBCL/6-18 DSM-oriented problem scales and the competence scales.

In 398 twin pairs belonging to the population-based Italian Registry, we investigated by the monozygotic twin intrapair differences model and bivariate designs whether the phenotypic correlations between CBCL/6-18 problem behaviours and competencies could better be accounted for by direct, causal effects, or by the presence of latent etiological factors, acting simultaneously as elements of risk/protection for psychopathology and competencies. All zero-order correlations between six CBCL DSM-oriented scales (DOS) and three competence scales (CS) were negative and small-to-moderate. After implementing multiple regressions we found robust enough prediction only for ADH DOS on school CS, and for anxiety DOS on social CS.

Clumsiness and psychopathology: causation or shared etiology? A twin study with the CBCL 6-18 questionnaire in a general school-age population sample.

In a sample of 398 twin pairs aged 8-17 belonging to the Italian Twin Registry we explored the extent to which physical clumsiness/motor problems covary with a broad spectrum of behavioral problems identified by the Child Behavior Checklist 6-18/DSM oriented scales, and the causes of such covariation. Only Anxiety and Attention Deficit Hyperactivity (ADH) Problems maintained significant correlation with Clumsiness after partialling out the effects of the other problem scales. By the co-twin control method we found no indication of clear, direct causal effect of Clumsiness upon Anxiety or ADH Problems, or vice versa.

The role of genes and environment in shaping co-occurrence of DSM-IV defined anxiety dimensions among Italian twins aged 8-17.

This study investigated the ultimate causes of co-variation between symptoms of four common DSM-IV anxiety dimensions - Generalized Anxiety, Panic, Social Phobia and Separation Anxiety disorder - assessed with the Italian version of the Screen for Child Anxiety-Related Emotional Disorders questionnaire in a sample of 378 twin pairs aged 8-17 from the population-based Italian Twin Register. Genetic and environmental proportions of covariance between the targeted anxiety dimensions were estimated by multivariate twin analyses. Genetic influences (explaining from 58% to 99% of covariance) and unique environmental factors were the sole sources of co-variation for all phenotypes under study.

A genetically informed study of the association between childhood separation anxiety, sensitivity to CO(2), panic disorder, and the effect of childhood parental loss.

Context: Childhood separation anxiety disorder can predate panic disorder, which usually begins in early adulthood. Both disorders are associated with heightened sensitivity to inhaled CO(2) and can be influenced by childhood parental loss.

Objectives: To find the sources of covariation between childhood separation anxiety disorder, hypersensitivity to CO(2), and panic disorder in adulthood and to measure the effect of childhood parental loss on such covariation.

A twin study of the common vulnerability between heightened sensitivity to hypercapnia and panic disorder.

For unknown reasons the inhalation of CO(2)-enriched air mixtures evokes acute panic-like symptoms in people with panic disorder and in their unaffected relatives. This study was set to determine whether, and to what extent, CO(2)-induced acute anxiety and panic disorder share the same genetic and environmental determinants. Cholesky structural equation models were used to decompose into genetic and environmental elements the correlation between self-assessed anxiety post-35%CO(2)-65%O(2) inhalation and interview-based DSM-IV lifetime diagnoses of panic disorder in 346 young adult twin pairs of the Norwegian Institute of Health Panel, 12% of whom had been invited to take part into the CO(2) study on the basis of self-reported symptoms of anxiety gathered 4-7 years before the provocation challenge.

The co-occurrence between internalizing and externalizing behaviors. A general population twin study.

Although Internalized and Externalized problem behaviors are described as separate phenomena at the psychometric and clinical levels, they frequently co-occur. Only few studies, however, have investigated the causes of such covariation. In a sample of 398 twin pairs aged 8-17 drawn from the general population-based Italian Twin Registry, we applied bivariate genetic analyses to parent-rated CBCL/6-18 Internalization and Externalization scores.

A general population twin study of the CBCL/6-18 DSM-oriented scales.

Objective: To explore the contributions of genetic and environmental influences to individual variation and covariation of the Child Behavior Checklist (CBCL) DSM-oriented scales (DOS) originally proposed by Achenbach and associates in 2001.

Method: A classic twin study of 398 twin pairs ages 8 to 17 years belonging to the population-based Italian Twin Registry, assessed by parents using the CBCL for Ages 6 to 18 (CBCL/6-18).

Results: Univariate analyses showed that compared with the classic CBCL/6-18 empirical subscales, the DOS have higher heritability (lowest 0.

A genetic study of the acute anxious response to carbon dioxide stimulation in man.

People with panic disorder-agoraphobia and their relatives often react anxiously to CO(2)-enriched gas mixtures. Available data are not suited to disentangle genetic from common environmental causes of familial aggregation of CO(2) reactivity, nor provide quantitative estimations of the sources of trait variation. Three-hundred-forty-six twin pairs belonging to the general population-based Norwegian NIPH Mental Health Study underwent self-assessments of anxiety and of DSM-IV panic symptoms after inhalation of a 35%CO(2)-65%O(2) mixture.