Socioeconomic status amplifies genetic effects in middle childhood in a large German twin sample.

The Scarr-Rowe hypothesis predicts that the heritability of cognitive abilities is higher in more privileged socioeconomic conditions, meaning that genetic potential can be more fully expressed in environments characterized by high socioeconomic status (SES) compared to low SES. This gene × SES interaction, however, has been replicated mostly in the United States, but not in other Western nations like the United Kingdom. In the current study, we tested the interaction between childhood SES and the heritability of cognitive ability in 3,074 German twin pairs comprising three age cohorts at different developmental stages (mean ages of 11, 17, and 23 years). Higher SES was associated with significantly higher mean cognitive ability scores in the two younger cohorts, with reduced variances at higher SES levels. Results further support the Scarr-Rowe hypothesis in middle childhood, and to some degree in adolescence, but not in adulthood. This indicates that the role of family SES as a moderator of the heritability of cognitive ability changes as children grow older. Moreover, children's shared experiences appear to be explain more variance in cognitive ability at the lower end of the SES distribution in middle childhood and adolescence.

Neighborhood deprivation and depression in adult twins: genetics and gene×environment interaction.

BACKGROUND: Depression is a significant problem and it is vital to understand its underlying causes and related policy implications. Neighborhood characteristics are implicated in depression but the nature of this association is unclear. Unobserved or unmeasured factors may confound the relationship. This study addresses confounding in a twin study investigating neighborhood-level effects on depression controlling for genetics, common environment, and gene×environment (G × E) interactions. METHOD: Data on neighborhood deprivation and depression were gathered from 3155 monozygotic twin pairs and 1275 dizygotic pairs (65.7% female) between 2006 and 2013. The variance for both depression and neighborhood deprivation was decomposed into three components: additive genetic variance (A); shared environmental variance (C); and non-shared environmental variance (E). Depression was then regressed on neighborhood deprivation to test the direct association and whether that association was confounded. We also tested for a G × E interaction in which the heritability of depression was modified by the level of neighborhood deprivation. RESULTS: Depression and neighborhood deprivation showed evidence of significant A (21.8% and 15.9%, respectively) and C (13.9% and 32.7%, respectively) variance. Depression increased with increasing neighborhood deprivation across all twins (p = 0.009), but this regression was not significant after controlling for A and C variance common to both phenotypes (p = 0.615). The G × E model showed genetic influences on depression increasing with increasing neighborhood deprivation (p < 0.001). CONCLUSIONS: Neighborhood deprivation is an important contributor to depression via increasing the genetic risk. Modifiable pathways that link neighborhoods to depression have been proposed and should serve as targets for intervention and research.

Parental depression and offspring psychopathology: a children of twins study.

BACKGROUND: Associations between parental depression and offspring affective and disruptive disorders are well documented. Few genetically informed studies have explored the processes underlying intergenerational associations. METHOD: A semi-structured interview assessing DSM-III-R psychiatric disorders was administered to twins (n=1296) from the Australian Twin Register (ATR), their spouses (n=1046) and offspring (n=2555). We used the Children of Twins (CoT) design to delineate the extent to which intergenerational associations were consistent with a causal influence or due to genetic confounds. RESULTS: In between-family analyses, parental depression was associated significantly with offspring depression [hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.20-1.93] and conduct disorder (CD; HR 2.27, CI 1.31-3.93). Survival analysis indicated that the intergenerational transmission of depression is consistent with a causal (environmental) inference, with a significant intergenerational association in offspring of discordant monozygotic (MZ) twin pairs (HR 1.39, CI 1.00-1.94). Logistic regression analysis suggested that the parental depression-offspring CD association was due to shared genetic liability in the parents and offspring. No intergenerational association was found when comparing the offspring of discordant MZ twins [odds ratio (OR) 1.41, CI 0.63-3.14], but offspring of discordant dizygotic (DZ) twins differed in their rates of CD (OR 2.53, CI 0.95-6.76). All findings remained after controlling for several measured covariates, including history of depression and CD in the twins' spouses. CONCLUSIONS: The mechanisms underlying associations between parental depression and offspring psychopathology seem to differ depending on the outcome. The results are consistent with a causal environmental role of parental depression in offspring depression whereas common genetic factors account for the association of parental depression and offspring CD.

Basic relations among lesion laterality, lesion volume and neuropsychological performance.

Although it is widely accepted that lesion size is an important determinant of severity of deficit, difficulties in the quantification of lesion size and the absence of a theoretical model of how lesion volume combines with lesion locus to produce deficits have inhibited the development of methodological and statistical procedures for studying naturally occurring lesions in humans. We propose such a unified model and apply it to the analysis of neuropsychological performance in a sample of patients with naturally occurring unilateral lesions. The analysis suggests that a statistical interaction between lesion size and laterality may be an important determinant of neuropsychological deficit.

Nonshared environment: a theoretical, methodological, and quantitative review.

When genetic similarity is controlled, siblings often appear no more alike than individuals selected at random from the population. Since R. Plomin and D. Daniels' seminal 1987 review, it has become widely accepted that the source of this dissimilarity is a variance component called nonshared environment. The authors review the conceptual foundations of nonshared environment, with emphasis on distinctions between components of environmental variance and causal properties of environmental events and between the effective and objective aspects of the environment. A statistical model of shared and nonshared environmental variables is developed. A quantitative review shows that measured nonshared environmental variables do not account for a substantial portion of the nonshared variability posited by biometric studies of behavior. Other explanations of the preponderance of nonshared environmental variability are suggested.

Heritability and biological explanation.

Modern neuroscientific and genetic technologies have provoked intense disagreement between scientists who envision a future in which biogenetic theories will enrich or even replace psychological theories, and others who consider biogenetic theories exaggerated, dehumanizing, and dangerous. Both sides of the debate about the role of genes and brains in the genesis of human behavior have missed an important point: All human behavior that varies among individuals is partially heritable and correlated with measurable aspects of brains, but the very ubiquity of these findings makes them a poor basis for reformulating scientists' conceptions of human behavior. Materialism requires psychological processes to be physically instantiated, but more crucial for psychology is the occasional empirical discovery of behavioral phenomena that are specific manifestations of low-level biological variables. Heritability and psychobiological association cannot be the basis for establishing whether behavior is genetic or biological, because to do so leads only to the banal tautology that all behavior is ultimately based in the genotype and brain.

Why the gap? Practice and policy in civil commitment hearings.

The failure of civil commitment procedures to meet statutory requirements is one of the more reliable findings in the applied social sciences. Most states now require specific legal procedures and behavioral standards for involuntary hospitalization. Nonetheless, empirical studies have demonstrated that commitment hearings are rarely adversarial and clinical concerns continue to take precedence over legal issues. These findings are analyzed in the context of three related issues: the grounds for commitment that are used in civil commitment hearings, the particular difficulties of recommitment hearings, and the shortcomings of the national policy of deinstitutionalization. The authors conclude that a primary cause of the gap between legal standards and actual practice is the absence of viable, less restrictive alternatives to inpatient treatment.

Morphological brain abnormalities in schizophrenia determined by computed tomography: a problem of measurement?

The size of the cerebral ventricles was estimated from computed tomographic (CT) scans of 14 young patients with schizophrenia and 12 medical controls. The subjects were a representative subsample from a larger sample studied by Boronow et al. (1985). Although no CT abnormalities were detected in the psychiatric patients using traditional measures (mechanical planimetry for the lateral ventricles and a linear measure for the third ventricle), a volumetric analysis of the same 26 scans revealed enlargement of the lateral and third ventricles in the schizophrenics. The effect revealed by volumetric measures of the lateral ventricles was 58% greater than that obtained with digital planimetry and 96% greater than the effect found using mechanical planimetry. No differences were found between volumetric and digital planimetric measures of the third ventricle, but the effect revealed by the latter measure was 114% greater than that obtained by a linear index. It is suggested that volumetric measures of lateral ventricles based on information from several CT slices may be more sensitive to group differences in ventricular size than planimetry. Likewise, area measures of the third ventricle may be more sensitive to group differences than linear measures.

Recollections of conflict with parents and family support in the personality disorders.

This study examined the relationships between personality disorders and retrospective reports of family support and conflict with parents. Participants were 798 United States Air Force recruits who were participating in a larger program of research on the peer assessment of personality disorders. Correlational analyses revealed consistent but modest associations between personality disorder features and both measures of family adversity. Borderline, antisocial, and paranoid features maintained small, unique associations after controlling for the general component of personality disorder. Further analyses, however, showed that differences among the correlations between personality disorder traits and family adversity measures account for little explained variance. In general, it does not appear that individual personality disorders have unique relations with retrospective reports of family adversity. Instead, the relation between personality disorders and family adversity seems to depend on a component common to all personality disorders.

Psychometric analysis of racial differences on the Maudsley Obsessional Compulsive Inventory.

Black university students scored significantly higher than White students on the Maudsley Obsessional Compulsive Inventory (MOCI). They tended to endorse more Cleaning and Checking subscale items in the pathological direction. Subsequent analyses examined whether this finding is a reflection of valid group differences in the prevalence of OCD or a psychometric artifact. Structured interviews were conducted to determine the correspondence of MOCI scores with OCD diagnoses. The race difference in endorsement frequency on the MOCI did not extend to OCD diagnoses. The MOCI scores showed modest predictive validity in Whites, but they did not predict interview-based diagnoses in Blacks. Multivariate item response theory was then employed to examine race differences in the Cleaning and Checking subscales. Equivalent item discrimination parameters fit the data for Black and White participants for both subscales. A more restrictive model in which relative item difficulties were also constrained to be equal for Black and White participants did not fit. This interaction between race and item difficulty suggests that the items do not have equivalent psychometric properties in Blacks and Whites.

Peer assessment of personality traits and pathology in female college students.

Assessment procedures for personality disorders (PDs) typically rely on self-reports, even though some people with PDs may be unable to view themselves realistically or are unwilling to report socially undesirable traits. Close associates may provide important information regarding the presence of PD traits. Peer nomination is a reliable and valid assessment procedure that can be adapted to the study of PDs for research purposes. This study focused on characteristic features that define narcissistic, dependent, and obsessive-compulsive PDs using information collected from both self and others in a nonclinical sample of women. It was designed to identify specific areas of agreement and discrepancy between self-report and peer assessment in the measurement of characteristic features of these disorders.

Multidimensional Representation of Decision-making in Chronic Schizophrenics.

We administered all paired comparisons of eight gambling stimuli to samples of inpatient schizophrenics, outpatient schizophrenics, and a comparison group of first-degree relatives. A matrix of pairwise preferences was elicited from each subject, and decomposed into a binary matrix indicating stimulus choice, and an unsigned dissimilarity matrix representing strength of preference. These matrices were analyzed using maximum likelihood multidimensional scaling methods, resulting in a representation of subjects and stimuli in an n-dimensional decision space. Results suggest that choice behavior of all groups was determined almost exclusively by the expected value of the stimuli, with no significant differences among the groups. Strength of preference was influenced by expected value for only the comparison group, with a much larger unsystematic component among the schizophrenic groups.

Length of hospitalization and outcome of commitment and recommitment hearings.

Despite extensive legislative reformulation of civil commitment procedures, empirical studies have shown that civil commitment hearings continue to be largely nonadversarial. The authors observed all civil commitment hearings during a three-month period at a large state hospital in Virginia and examined the characteristics of patients and the actions of attorneys, clinical examiners, and judges as a function of the length of time the patient had been in the hospital. The analysis revealed that as the length of a patient's hospitalization increased, the hearings became shorter and less adversarial; patients tended to show fewer signs of acute psychiatric illness and more signs of chronic schizophrenia. The implications of these findings for civil commitment policy are discussed.

Touch relieves stress and pain.

There are few systematic investigations of the potential benefits of incidental touch as it occurs in medical health care settings. In the present laboratory study 60 college students participated in two testing sessions 1 month apart. These sessions involved counterbalanced conditions of baseline, pulse palpation (touch), cold pressor test (stressor), and combined cold pressor/pulse palpation. Heart rate and systolic and diastolic blood pressure were measured during each condition. Subjective pain ratings were recorded during stress conditions. Significant decreases in cardiovascular measures and pain ratings were associated with physical contact. However, these changes were small and individual responses to physical contact were not stable over time. Physical contact produces a small but significant decrease in cardiovascular variables and the experience of pain. However, the tendency to show a cardiovascular response to touch does not represent a stable trait for individuals in the laboratory setting.

Volumetric asymmetries of the human brain: intellectual correlates.

Volumetric measures of the brain and ventricles were derived from CT films and related to intellectual variables from the Wechsler Adult Intelligence Scale (WAIS). Subjects were patients referred for neurological examination for headache or somatic complaints, sometimes accompanied by anxiety or dysphoric affect (N = 41), for whom a comprehensive neurological work-up revealed no evidence of abnormality. The asymmetry of hemispheric volume (left minus right over total, times 100) was correlated (r = .57, p less than .001) with Verbal IQ minus Performance IQ within subjects. No relationship was observed between total brain or hemispheric volumes and IQ scores. Brain and ventricular volumes were larger for the left hemisphere than the right.

Quantitative assessment of covariation between neuropsychological function and location of naturally occurring lesions in humans.

Studies of localization of brain function in humans depend on analysis of covariation between the location of naturally occurring lesions and measures of neuropsychological ability. Such an analysis presents two problems: how to represent numerically the infinite variety of lesion locations, sizes, and shapes; and how to assess covariation between the location measure and performance. We present a mathematical model of lesion location and its relationship with performance. To demonstrate its utility, the model is applied to a sample of 53 patients with naturally occurring brain lesions who were administered a standard battery of neuropsychological tests. Importance functions derived for the neuropsychological measures generally conform to expectations. Sensory and motor abilities were localized correctly within the contralateral hemispheres, and language functions were localized in the left frontal region. Lesion location accounts for substantially more variation in performance than does lesion volume, with location accounting for more than 50% for some left-hemisphere functions.

Intellectual and memory impairment in dementia. Computerized axial tomography volume correlations.

Ventricular volume estimates and an index of cerebral atrophy were obtained from computerized axial tomography scans of patients with presenile or senile dementia of probable Alzheimer's type. These measures were used to examine the correlation between morphological brain change and performance on the Wechsler Adult Intelligence Scale (WAIS) and the Wechsler Memory Scale (WMS). Despite ventricular volumes in excess of 60% larger than normal, no significant correlations were found between ventricular size and WAIS or WMS performance. The index of pericerebral atrophy did correlate negatively with various WAIS measures, particularly Performance IQ, and some aspects of WMS performance. Results suggest that in Alzheimer's disease, pericerebral atrophy measures, but not ventricular dilation, correlate with intellectual decline and certain aspects of memory impairment.

Relationship between cognitive and morphological asymmetry in dementia of the Alzheimer type: a CT scan study.

In this study we investigated the association between morphological asymmetry and patterns of cognitive ability in dementia of Alzheimer's type (DAT). Digitized CT scans were used to estimate volumetric parameters of the brain. The volume of the cranium, brain parenchyma, the subarachnoid space, and lateral ventricles was computed. The volume of the subarachnoid space was used as an index of cortical atrophy, while the ventricular volume served as an estimate of subcortical atrophy. Asymmetry indices were computed for all structures as the difference between left and right volume divided by their average and multiplied by 100. Cognitive asymmetry index was computed by dividing the difference between VIQ and PIQ of the Wechsler Adult Intelligence Scale (WAIS) by their average and multiplying by 100. After statistically controlling for cranial asymmetry, hemispheric asymmetry was found to correlate positively with cognitive asymmetry. The correlation was somewhat greater for male than for female patients. Asymmetry of both cortical and subcortical atrophy correlated negatively with cognitive asymmetry.

The fetal-pelvic index has minimal utility in predicting fetal-pelvic disproportion.

OBJECTIVE: Our purpose was to evaluate the fetal-pelvic index in our patient population and to determine whether it would be predictive of route of delivery. STUDY DESIGN: One hundred seventy-six patients with a previous history or clinical findings in the current pregnancy suggestive of fetal-pelvic disproportion participated in this Human Investigation Committee-approved study. All underwent fetal ultrasonographic examinations and modified digital radiography before labor. Fetal head and abdominal circumferences and maternal inlet and midpelvic circumferences were determined, and the fetal-pelvic index was calculated. RESULTS: Ninety-one patients fulfilled all aspects of the study, including rigorous criteria pertaining to labor management. Thirty of these patients underwent cesarean delivery and 61 were delivered vaginally. The fetal-pelvic index value for the vaginal delivery group was -5.4 +/- 5.3, as opposed to -2.4 +/- 5.8 in the cesarean delivery group (P <.02). Notwithstanding this difference, the fetal-pelvic index had a low overall ability to predict fetal-pelvic disproportion (0.65) and had associated sensitivity and specificity of 0.27 and 0.84, respectively. Predictive thresholds other than zero were tested, but optimal predictive ability, at a fetal-pelvic index cutoff of 2, was only 70% (sensitivity 0.20, specificity 0.95). CONCLUSION: In our patient population the fetal-pelvic index was only moderately predictive of fetal-pelvic disproportion. Factors other than those assessed by the fetal-pelvic index are probably important in determining the route of delivery. Further studies are indicated.