Behavioral and molecular genetic contributions to a dimensional classification of personality disorder

This article examines the possible contribution of behavioral and molecular genetic research to the development of a dimensional classification of personality disorder. It is argued that the results of molecular studies are too preliminary to have immediate nosological significance. However, behavioral genetic methods could play a useful role in constructing a classification that reflects the genetic architecture of personality disorder. It is also argued that the best approach to constructing a valid classification would be to integrate behavioral genetic methods with the construct validation framework used in test construction. An integrative approach is proposed that seeks to combine constructs from alternative dimensional models. It is suggested that strong evidence of a four-dimensional structure to personality disorder provides a way to organize a preliminary model. An initial set of primary traits to define these secondary domains would then be compiled from existing models and refined using a combination of traditional psychometric analyses and behavioral genetic methods. It is concluded that an etiologically based classification is feasible for the DSM-V.     

Behavioral Genetics as a Tool for Developmental Psychology: Anxiety and Depression in Children and Adolescents

Over the past decade there has been a huge increase in the number of behavioral genetic studies looking into anxiety and depression in children and adolescents. There are now enough data in this area to make a review of the results useful. This paper begins with an outline of the methods used in such research and moves on to review the results in extant studies. Overall, these studies indicate modest to moderate genetic influence on both anxiety and depression. However, behavioral genetic methods are also paramount for exploring environmental influences in addition to genetic influences. Shared environment (that which makes family members resemble one another) is rarely identified in adult studies of personality or psychopathology and does not appear to be a significant influence for depression but it is for anxiety. Nonshared environment, which makes family members differ from one another, is found to be a significant influence for both anxiety and depression. Patterns within these results due to rater effects, age effects, sex effects, the precise phenotype measured, and the study design are explored.     

Separated twins and the genetics of personality differences: a critique

This article discusses studies of separated twins, with special emphasis on the Minnesota Study of Twins Reared Apart (MISTRA), to determine whether they support the existence of an important genetic component in behavioral and personality differences. The methods and conclusions of the MISTRA team are discussed in the context of earlier studies of separated identical twins. I argue that volunteer-based studies are biased toward greater twin similarity. In addition, the MISTRA research team did not publish or share raw data and case history information. Reared-together and reared-apart monozygotic twins share important environmental similarities not controlled for by comparing personality correlations. I propose an alternative control group consisting of biologically unrelated pairs of strangers matched on all environmental factors common to pairs of separated monozygotic twins. I conclude that the evidence from studies of twins reared apart does not support the role of genetic factors in personality and behavioral differences.     

Environment and genes. Determinants of behavior

Recent behavioral genetic research has demonstrated that genetic influence on individual differences in behavioral development is usually significant and often substantial and, paradoxically, also supports the important role of the environment. This article reviews research on the heritability of intellectual factors, personality factors, and psychopathology. It discusses the importance of investigating within-family environmental differences in order to understand the environmental origins of individual differences in development.     

Behavioral Genetics and Personality Change

Although research on personality and behavioral genetics has focused on the continuity of traits, both fields and their interface will profit from the consideration of trait change. In this article we review personality research on age differences in heritability and propose the counterintuitive hypothesis that, when developmental changes in heritability are found, heritability tends to increase. We also focus on behavioral genetic analyses of long-term developmental change. Research to date suggests that genetic involvement in adult personality change is slight whereas personality change in childhood is governed substantially be genetic factors. Finally, we consider a new topic, genetic influence on short-term change in personality.     

A genetic factor explains most of the variation in the psychopathic personality

The psychopathic personality can be conceptualized as three interrelated dimensions, (a) an interpersonal style of glibness, grandiosity, and manipulation; (b) an affective disposition of callousness, lack of empathy, and unemotionality; and (c) a behavioral/lifestyle dimension of impulsivity, need for stimulation, and irresponsibility, underpinning a higher order construct, psychopathic personality. The authors used a self-report questionnaire (The Youth Psychopathic Traits Inventory) to study the importance of genetic and environmental influences on psychopathic personality traits in a sample of 1,090 monozygotic and dizygotic twin pairs, aged 16-17 years. Results showed a strong genetic influence behind the higher order "psychopathic personality" factor, underpinned by the three psychopathic personality dimensions. Over and above the effects to the higher order factor, significant unique genetic influences were also found in the callous/unemotional and in the impulsive/irresponsible dimension, but not in the grandiose/manipulative dimension. The authors propose that this latent psychopathic personality factor is a meaningful target for future etiological research.     

A behavioral genetic study of the overlap between personality and parenting

The current study had three aims. The first was to examine the covariation between personality of parents and parenting behaviors. The second aim was to examine the genetic and environmental influences on parenting behaviors. The third aim was to examine the extent to which the association between personality and parenting was mediated by genetic and environmental factors. Personality (Five Factor Model, NEO-FFI) and parenting data were collected as part of a larger German study of 300 adult twin pairs (GOSAT). The current paper analyzes data on a subset of the 300 twin pairs from the GOSAT sample who were concordant for having children (n=98 pairs or 196 individuals). Results indicated modest overlap between personality and parenting. In addition, univariate behavioral genetic analyses indicated moderate genetic influence on select parenting dimensions. Results also indicated that the moderate phenotypic covariation between personality and parenting was attributed largely to nongenetic factors. Implications of the findings for research on parenting and personality are considered.     

Stability and change in personality pathology: revelations of three longitudinal studies

Three major longitudinal studies of personality disorder jointly provide new insights into the nature of stability and change in this important domain of psychopathology. This commentary highlights some of the many convergent results, which indicate robust findings that can be considered "established," and also differences in the studies' purposes and methods that permit each study to make unique contributions. One of the most important findings across the studies is that DSM- diagnosed personality disorder is not as stable as the characteristic traits that underlie personality pathology, leading to the insight that DSM personality disorders are hybrids of more acute, "Axis I-like" symptoms that resolve more quickly and longer lasting affective, cognitive, and behavioral personality dysfunctions. Implications for future research are considered.     

发展行为遗传学简介

发展行为遗传学是发展心理学与行为遗传学的交叉学科, 旨在探明遗传与环境对人类心理与行为发展是否存在影响, 如何产生影响, 以及该影响及其作用机制是否随年龄增长而发展变化的问题。该学科与行为遗传学在研究对象、设计和内容等方面存在不同; 开展发展行为遗传学研究需要综合运用心理测量法和行为遗传学研究方法; 未来研究应拓宽和深化候选基因与行为关联性的考察, 并着力探析基因与环境的相互作用机制。     

人格研究中的行为遗传学取向的发展

人格的行为遗传学研究,是以研究遗传和环境的差异来解释人格的个体差异的程度为目的,为探讨遗传和环境在个体发展中的作用提供了新的研究途径。该文以天性和教养为突破口,紧紧围绕行为遗传学在人格研究领域的发展脉络:遗传力、环境、特定基因的研究,进一步探讨在个体人格发展过程中遗传和环境的交互作用的关系。     

As the Twig Is Bent? The Myth of Child-Rearing Influences on Personality Development

Social scientists and laypersons alike believe that child-rearing styles and family environments are formative of personality traits such as shyness and activity level, intellectual traits such as IQ, and psychopathology. After 100 years of behavioral genetic research, however, including new studies of twins raised apart and together, little factual support for this “common sense” proposition can be found. Nonintellectual traits seem to be determined instead by genetic influences and by relatively specific environmental influences, most of which are not particularly tied to the family or parental treatments. Intellectual traits show modest family environmental influence, but that influence may diminish in importance after childhood. I conclude that parents should be given less credit for children who turn out well and should take less blame for children who turn out poorly. Counselors who blame parents less for children's behavioral outcomes—especially extreme traits and psychopathology—may find those parents to be more willing helpers in those intervention processes that have been shown to work.     

Evolutionary biology and personality psychology: Implications of genetic variability

Biological considerations raise an important set of issues for psychology: what behavioral attributes of the species are genetically based, what are the mechanisms by which genetic influences affect behavior, what are the evolutionary antecedents of genetically-based attributes, and what are their consequences? This article examines a subset of these issues by exploring some potential consequences of extant genetic variability for personality functioning, social interaction and the current genetic evolution of our species. Behavior genetics provides a methodology for discovering genetically-influenced behavioral variation. Five disparate areas (socialization, personality development, personality assessment, interactionism and assortative mating) are examined in which findings from behavior genetics can guide research and theory in personality psychology. Relationships between organismic and social parameters are emphasized. The final section combines these five areas by placing them within the broader context of theory-building in psychology.     

Genetic and Environmental Contributions to Individual Differences: The Three Major Dimensions of Personality

ABSTRACT This article deals with the contribution of genetic and environmental factors to individual differences in the three major dimensions of personality (Psychoticism, Extraversion, and Neuroticism) Twin studies indicate, and family studies confirm within limits, the strong genetic determination of these and many other personality factors, additive genetic variance accounting for roughly half the total phenotypic variance On the environmental side, shared family environment plays little or no part, all environmental effects being within-family Assortative mating, important in the formation of social attitudes, has little impact on personality Dominance may be important for Extraversion Epistasis (emergenesis) may account for the comparative low values of dizygotic (DZ) twins' correlations Evidence for differential heritability of traits is present, but not very strong It is concluded that behavioral genetics forms a vital part of the psychological understanding of the causes of individual differences in personality     

Engineering technology and behavior analysis for interdisciplinary environmental protection

Engineering strategies for saving environmental resources have been widespread. However, many of those engineering advances have not been widely accepted nor generally applied by large segments of the general population. This paper considers the need to examine behavioral/environmental variables in the application of engineering technology, with particular reference to specific behavioral strategies for encouraging the use of engineering technology from an interdisciplinary perspective. A model for the study of factors contributing to the solution of ecological/environmental problems is presented and examples of interdisciplinary research are described. The model implies a need for the examination of the effects of antecedent and consequent manipulation of a variety of variables including: behavioral, physiological, environmental, technical and legal conditions. It is concluded that while interdisciplinary research efforts between engineering technologists and behavioral analysts are necessary, they have not received sufficient attention in the literature nor have they focused on the comprehensive study of antecedents and consequences as they relate to ecological/environmental problems. Thus, an extended "family" of research efforts is important for the success of these efforts.     

Why Are Siblings So Different? The Significance of Differences in Sibling Experiences Within the Family

Siblings, who are 50% similar genetically and grow up within the same family, nevertheless differ markedly in personality and psychopathology, and most of these sibling differences cannot be explained by genetic factors. These findings from the field of behavioral genetics imply that within-family processes that lead to sibling differences, called nonshared environment, are crucial for understanding environmental influences on individual development. Such nonshared environmental influences cannot be identified by the conventional strategy of comparing one child per family on a family-by-family basis; what is needed are studies of siblings that focus on why they are so different. The implications of these findings for investigating family process are outlined, and research is reviewed that explores the extent to which siblings in a family have different experiences, and that begins to assess links between such differential experiences and developmental outcomes.     

Normal and abnormal personality traits: evidence for genetic and environmental relationships in the Minnesota Study of Twins Reared Apart

ABSTRACT Recent studies have demonstrated substantial correlations between normal and abnormal personality traits. Yet little is known about how these correlations are mediated genetically and environmentally: Do normal and abnormal personality traits stem from the same underlying genes and environments? We addressed this question using data from 128 monozygotic and dizygotic twin pairs in the Minnesota Study of Twins Reared Apart (MISTRA). Additive genetic and nonshared environmental correlations between scales of the Minnesota Multiphasic Personality Inventory (MMPI)—an index of abnormal personality—and the Multidimensional Personality Questionnaire (MPQ)—an index of normal personality—were estimated. Results indicated that phenotypic correlations between normal and abnormal personality were mediated by genetic as well as environmental factors, although the magnitude of genetic mediation tended to be larger overall. Moreover, the patterns of phenotypic, genetic, and environmental relationships among the scales were similar, suggesting that influences on normal and abnormal personality act through systems common to both. It is suggested that future research focus on the neurogenetic substrates of these shared systems and how dysfunction in these systems influences development of disordered personality.     

Taxometric and related methods in relationships research

Research on personal relationships inescapably uses taxonomies for classifying people, relationships, and interpersonal processes and events, and often develops new ones. However, constructing a good taxonomy is no simple matter. Many existing classification methods have serious weaknesses, and they carry the risk of drawing taxonomic distinctions that are spurious. In addition, researchers frequently make unwarranted assumptions about the nature of the taxonomic categories that they employ in their work. This article introduces a family of quantitative methods for testing and generating taxonomies. Although they have seen little use to date outside of psychopathology, personality psychology, and behavioral genetics, these methods are versatile and readily adapted to the domain of personal relationships, where they offer many research possibilities. Three of the methods are illustrated in a study of elementary forms of relationships.     

An Interactionist Perspective on Genetic and Environmental Contributions to Personality

It is now well established that nature and nurture are both important contributors to variation in human personality. As a result, the field of personality behavior genetics is moving beyond simply estimating the magnitude of genetic and environmental influences on various personality constructs. Recent methodological advances provide for the study of how these different sources of influence interact in the development of personality. Specifically, newer biometrical moderation models allow for group‐specific estimates of heritability and environmental influences on personality (a form of gene–environment interaction). In the current paper, we review selected recent research using these models. Furthermore, we explore how moderation might also be important in understanding links between specific genes and personality. Accounting for the contingencies between genes and environment will be an important catalyst for the molecular genetic study of personality, as unmoderated ‘main effect’ types of gene → personality associations have been elusive.