Genetic probes of three theories of maternal adjustment: I. Recent evidence and a model.

Studies focusing on genetic and social influences on maternal adjustment will illumine mother's marriage, parenting, and the development of psychopathology in her children. Recent behavioral genetic research suggests mechanisms by which genetic and social influences determine psychological development and adjustment. First, heritable, personal attributes may influence individuals' relationships with their family members. These genetically influenced family patterns may amplify the effects of adverse, heritable personal attributes on adjustment. Second, influences unique to siblings may be the most important environmental determinants of adjustment. We derive three hypotheses on maternal adjustment from integrating these findings from genetic studies with other contemporary research on maternal adjustment. First, mother's marriage mediates the influence of her heritable, personal attributes on her adjustment. Second, mother's recall of how she was parented is partially genetically influenced, and both her relationships with her spouse and her child mediate the impact of these genetically influenced representations on her current adjustment. Third, characteristics of mother's spouse are important influences on difference between her adjustment and that of her sister's. These sibling-specific influences are unrelated to mother's heritable attributes. The current article develops this model, and [figure: see text] the companion article describes the Twin Mom Study that was designed to test it as well, as its first findings. Data from this study can illumine the role of family process in the expression of genetic influence and lead to specific family interventions designed to offset adverse genetic influences.     

青少年抑郁情绪的行为遗传学研究

本研究意在探讨青少年抑郁情绪遗传率的性别和年龄差异及遗传和环境对抑郁情绪跨时间连续性的影响。508对同卵双生子, 176对同性别异卵双生子参加了两轮追踪研究, 时间间隔约为一年半(1.37±0.44)。第一轮测量双生子的年龄范围为10~18岁, 平均年龄为13.69±2.04岁, 男生比例为46.2%。采用儿童抑郁量表(CDI)对青少年的抑郁情绪进行多报告者评定。结果发现, 青少年抑郁情绪的遗传解释率不存在性别差异, 处于青春早期青少年的遗传解释率高于青春中期的青少年。遗传是影响青春早期青少年抑郁情绪持续发生的主导因素, 而环境是影响青春中期青少年抑郁情绪持续发生的主要因素。     

Toward an Evolutionary History of Female Sociosexual Variation

ABSTRACT Considerable progress has been made in behavioral genetics toward providing theoretical accounts of individual differences One theoretical task, however, has been largely neglected—that of constructing evolutionary accounts of behaviorally relevant genetic variance We attempt to address this task with respect to the genetic variance underlying sociosexuality, that is, the differences in the implicit prerequisites (in terms of time, attachment, commitment, etc) to entering a sexual relationship Specifically, we argue that genetic variance on this trait for females could have been maintained through frequency-dependent selection In our evolutionary past, restricted females-those who require relatively more time, attachment, and commitment-could have benefited through paternal investment in their offspring Unrestricted females—those who require relatively less time, attachment, and commitment—could have benefited through the quality of their mate's genes passed on to their sons Moreover, the value of these alternate „strategies” could have been frequency-dependent One prediction that follows from this evolutionary history is tested and supported in three studies Those females genetically predisposed to be unrestricted are found to produce relatively more sons than females predisposed to be restricted Additional predictions are offered and alternative accounts are discussed     

Genetic and environmental explanations of juvenile violence in advantaged and disadvantaged environments

This study tests the proposition derived from behavioral genetic theory that genetics and environmental variables have different effects across different environments. I examine the effects of intellectual imbalance [performance IQ (P) significantly greater than verbal IQ (V)] a variable assumed to be heritable to some extent, and love deprivation, a composite variable consisting of various indices of parental abuse and neglect, on violent delinquency within different socioeconomic status (SES) environments. The findings are consistent with behavioral genetic theory, in that love deprivation could not explain any unique variance in violent delinquency after P > V explained all that it could in the advantaged environment (49.5%), and P > V could not explain any unique variance in the disadvantaged environment after love deprivation explained all that it could (28.8%). It was also found that love deprivation explains a highly significant 30.5% of the variance in P > V among SES-disadvantaged subjects, thus supporting those who posit that environmental disadvantages contribute significantly to intellectual imbalance. © 1992 Wiley-Liss, Inc.     

Preliminary evidence that specific candidate genes are associated with adolescent-onset antisocial behavior

Though initially conceptualized as resulting from peer imitation of child-onset or life-course-persistent youth [Moffitt, 1993], there is mounting evidence from twin studies that adolescent-onset or adolescent-limited antisocial behavior may also be genetically influenced. This study sought to provide preliminary molecular genetic evidence in support of these findings. We further evaluated whether genetic associations varied between behavioral subtypes of ASB (i.e., physical aggression and nonaggressive rule-breaking), given that only the latter has been found to characterize adolescent-onset ASB. The sample consisted of 211 undergraduate men of European-American ancestry. Three polymorphisms with theoretical and/or empirical ties to ASB or related traits (i.e., tryptophan hydroxylase-A218C, 5HT(2A) His452Tyr, and the DAT1 variable nucleotide tandem repeat) were genotyped. Analyses revealed that two of the three polymorphisms (i.e., His452Tyr and DAT1) were associated with adolescent ASB. Moreover, these associations appeared to be specific to the nonaggressive, rule-breaking form of ASB, and did not extend to physical aggression, further supporting ties to adolescent ASB in particular. Such results thus constructively replicate earlier findings of genetic influence on adolescent ASB. They also offer preliminary evidence that the genetic processes underlying aggressive and nonaggressive antisocial behavior may be (at least partially) distinct.     

非药物成瘾的遗传学和神经生物学机制研究述评

非药物成瘾又称“非物质相关性成瘾”或“行为成瘾”。特征性表现包括对成瘾对象的渴望、受损的冲动控制、对成瘾对象的耐受、撤退反应和高复发率等。目前发现的非药物成瘾类型包括病理性赌博、网络成瘾、购物成瘾、游戏成瘾、性瘾以及贪食等。非药物成瘾与药物成瘾在症状学上表现出很高的相似性且具有较高的共病率, 提示二者之间可能存在着共同的发病机制。从遗传学和神经生物学的角度探讨非药物成瘾的机制具有重要的理论价值和临床应用价值。家庭研究和双生子研究发现, 男性的病理性赌博和贪食障碍具有中度以上的遗传度。分子遗传学研究发现, 单胺能神经递质相关基因, 如5-羟色胺转运体基因、多巴胺受体基因和单胺氧化酶A基因等, 与非药物成瘾有关。神经影像学研究发现, 非药物成瘾者脑内负责奖赏,线索加工和冲动控制的神经通路活动性异于正常对照。未来研究需要进一步从多个角度入手, 探讨非药物成瘾与药物成瘾的共性和特性。     

Behavioral Intentions: Which Ones Predict Fertility Behavior in Married Couples?1

The published literature on the relationship between behavioral intentions and fertility behavior exhibits four major problems: inconsistent and confusing use of theoretical constructs, limited use of different types of intentions, use of nonbehavioral outcomes, and failure to explore adequately the couple aspects of the intentions/behavior relationship. The study reported here addresses these problems by using a theoretical framework that characterizes the psychological/behavioral sequence leading to a planned conception, three different types of fertility intentions, a behavioral outcome variable, and data from 196 married couples with no children and 185 married couples with one child. Data analysis results in a simultaneous equation, constrained regression model which indicates that child-timing intentions are the most important predictors of proceptive behavior over a 3-1/2 year period and that childbearing intentions are next in importance; that behavioral intentions are the final common pathway through which fertility motivations, attitudes, beliefs, and desires affect behavior; that the use of proceptive behavior as an outcome variable improves the explanatory power of our models; and that the interaction of couple intentions do not demonstrate greater husband or wife influence over couple proceptive behavior but do demonstrate that disagreement has a delaying effect on the onset of that behavior.     

Evaluating the Impact of Genetic Counseling and Testing with Signal Detection Methods

One measure of the impact of genetic counseling and testing (GCT) is the extent to which it fosters behavioral change that is consistent with mutation status. We describe and illustrate how two different signal detection methods, receiver operating characteristic (ROC) analysis and recursive partitioning, can be used in this context to evaluate the impact of GCT. We analyzed real screening behavior data obtained in the 12 months following GCT for Hereditary Nonpolyposis Colon Cancer (HNPCC) using these two different signal detection approaches. Each approach demonstrated that GCT had an impact on behavioral outcomes, and was effective in fostering behavioral outcomes appropriate to mutation status. The ROC approach demonstrated that GCT was effective because mutation positive and mutation negative individuals could be distinguished on the basis of the number of recommended screening behaviors. The recursive partitioning approach demonstrated that GCT was effective because there were generally high rates of adherence to screening guidelines among subjects. The recursive partitioning technique also identified four subgroups of subjects, each with distinct characteristics, for which tailored interventions could be developed to increase rates of adherence to screening guidelines. Signal detection methods are easily implemented and are useful techniques for evaluating the impact of GCT.     

Behavior Genetics: What's New? What's Next?

What's new in behavior genetics? With widespread acceptance that nearly all behavioral variation reflects some genetic influence, current studies are investigating developmental changes in the nature and magnitude of genetic and environmental effects, the extent to which different behaviors are influenced by common genes, and different forms of gene-environment correlation and interaction. New designs, focused on assessment of unrelated children in the same households or neighborhood environments, and use of measured environmental variables within genetically informative designs, are yielding more incisive evidence of common environmental effects on behavior. What will be next? Behavior genetic techniques and analyses will be used to inform efforts to find genes altering susceptibility for disorder and dispositional genes affecting behavioral variation. The developing integration of behavioral and molecular genetics will identify genes influencing specific behavioral variation and enhance understanding of how they do so. Psychologists will play a pivotal role in communicating that understanding to the public and in facilitating consideration of the inevitable ethical issues then to be confronted.     

Molecular Genetic Studies of Eating Disorders: Current Status and Future Directions

ABSTRACT— We review association studies that have examined the genetic basis of eating disorders. Overall, findings suggest that serotonin, brain-derived neurotrophic factor, and estrogen genes may be important for the development of the disorders. These neuronal systems influence behavioral and personality characteristics (e.g., anxiety, food intake) that are disrupted in eating disorders. Future studies would benefit from larger sample sizes and inclusion of behavioral and personality covariates in analyses. Consideration of the mechanisms of genetic effects and interactions between genes and environment is also needed to extend conceptualizations of the genetic basis of these disorders.     

主动性攻击和反应性攻击的遗传基础研究述评

根据攻击行为的意图可以将攻击分为主动性攻击和反应性攻击。近年来, 研究者对遗传和环境在主动性攻击和反应性攻击发展中的作用进行了探讨, 并获得了两类攻击具有不同遗传和环境基础的重要发现。既有研究主要采用定量行为遗传学研究的范式考察两类攻击的遗传基础, 未来研究应从确定与两类攻击相关的候选基因、遗传基因与环境的交互作用机制、遗传基因作用于两类攻击的神经生物机制等方面展开。     

Genetic Disorders of Intellectual Disability: Expanding our Concepts of Phenotypes and of Family Outcomes

Over the past two decades, great strides have been made in our understandings of how genetic conditions influence behavior and how such so-called “behavioral phenotypes” influence parent and family stress and coping. In this paper, we call for expansions in two directions. First, as a field we need to go beyond behavior in our concepts of phenotypes, to also include the many medical, physical, and other “non-behavioral” phenotypes that influence children’s everyday lives. Second, in examining how etiology-related phenotypes affect others, we need to go beyond the outcome of parental stress. In this regard, we focus on parental health, well-being, and various life choices, as well as how parenting children with specific genetic disorders can often lead to positive perceptions and outcomes. We end by discussing remaining research issues and how these two expansions relate to clinical practice.     

Sources of Variance in Personality Facets: A Multiple‐Rater Twin Study of Self‐Peer,Peer‐Peer,and Self‐Self (Dis)Agreement

ABSTRACT This study considered the validity of the personality structure based on the Five‐Factor Model using both self‐ and peer reports on twins' NEO‐PI‐R facets. Separating common from specific genetic variance in self‐ and peer reports, this study examined genetic substance of different trait levels and rater‐specific perspectives relating to personality judgments. Data of 919 twin pairs were analyzed using a multiple‐rater twin model to disentangle genetic and environmental effects on domain‐level trait, facet‐specific trait, and rater‐specific variance. About two thirds of both the domain‐level trait variance and the facet‐specific trait variance was attributable to genetic factors. This suggests that the more personality is measured accurately, the better these measures reflect the genetic structure. Specific variance in self‐ and peer reports also showed modest to substantial genetic influence. This may indicate not only genetically influenced self‐rater biases but also substance components specific for self‐ and peer raters' perspectives on traits actually measured.     

阅读能力个体差异的遗传基础—— 双生子研究的元分析

阅读能力的个体差异来源是行为遗传学的研究焦点之一。文章通过对80个阅读双生子研究的元分析发现：(1)遗传对阅读及其加工过程、基本认知技能具有中等强度影响; (2)不同阅读加工成分既受到共同遗传因素的作用, 又同时受到特异遗传因素的影响。(3)阅读与一般认知能力、数学能力在遗传上存在中等强度相关。这些结果表明了双生子研究对探索阅读的遗传机制具有分子遗传学所不可替代的价值, 文章还提出了如提升行为表型的测查质量等对未来研究的具体建议。     

Evidence for bivariate systems: An empirical test of appetition and aversion across domains

Research in diverse domains of psychology has independently identified two behavioral systems, one concerned with obtaining positive outcomes, the other concerned with avoiding negative outcomes. This basic distinction, described in different domains of inquiry with varying terminology, may be integrated within a single appetitive–aversive systems model. The present research was designed to examine the viability of the appetitive–aversive distinction as an organizational construct underlying various particular measures and concepts. In four studies, individual difference measures from different domains were examined with exploratory (Study 1) and confirmatory (Studies 2–4) factor analyses. We expected and found that measures tapping sensitivity to rewards or positive outcomes would load on a common appetitive latent factor, whereas, measures tapping individual differences in sensitivity to punishment or negative outcomes would load a common aversive latent factor. Results strongly supported the hypothesized two-factor structure over alternative models and indicated that the latent appetitive and aversive variables accounted for about half the variance in the observed variables.     

Genetic counselling: Predicting patient outcomes

Abstract

With the rapid development of genetic testing, the demand for genetic counselling is increasing. Yet there is little known about what makes for effective or efficient genetic counselling. The aim of the current study is to determine the main factors influencing outcomes of genetic consultations. One hundred and thirty one routine consultations conducted in a regional genetics centre were audiotaped, transcribed and coded. The main predictors of outcome tested were pre-interview patient and counsellor expectations; pre-interview patient concerns; length of consultations; counsellor directiveness; and the extent to which social and emotional issues are addressed in the consultation. The main outcomes were the patient's view of the extent to which their expectations were met, their satisfaction with information provided, and concern about the problem they were referred with.

Although there were six significant correlations between the process of consultation and outcome variables, multivariate analyses revealed no significant predictors of any of the outcomes. Using multiple regression analyses, small amounts of variance in patient outcomes were predicted by patient and counsellor variables assessed before the consultation, but none was predicted by any of the process measures made of the consultation. Various explanations are considered to explain the lack of influence of process variables upon outcomes. One possible explanation for these findings is that the consultation has a minimal effect upon patient outcomes. Alternatively, the study, in design or analysis, was not sufficiently sensitive to detect the influential aspects of the consultation.     

Ethical Concerns About Human Genetic Enhancement in the Malay Science Fiction Novels

Advancements in science and technology have not only brought hope to humankind to produce disease-free offspring, but also offer possibilities to genetically enhance the next generation’s traits and capacities. Human genetic enhancement, however, raises complex ethical questions, such as to what extent should it be allowed? It has been a great challenge for humankind to develop robust ethical guidelines for human genetic enhancement that address both public concerns and needs. We believe that research about public concerns is necessary prior to developing such guidelines, yet the issues have not been thoroughly investigated in many countries, including Malaysia. Since the novel often functions as a medium for the public to express their concerns, this paper explores ethical concerns about human genetic enhancement expressed in four Malay science fiction novels namely Klon, Leksikon Ledang, Transgenesis Bisikan Rimba and Transgenik Sifar. Religion has a strong influence on the worldview of the Malays therefore some concerns such as playing God are obviously religious. Association of the negative image of scientists as well as the private research companies with the research on human genetic enhancement reflects the authors’ concerns about the main motivations for conducting such research and the extent to which such research will benefit society.     

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.     

Exploring gene-environment interactions: socioregional moderation of alcohol use.

Examples of gene-environment interaction in human behavioral data are relatively rare; those that exist have used simple, dichotomous measures of the environment. The authors describe a model that allows for the specification of more continuous, more realistic variations in environments as moderators of genetic and environmental influences on behavior. Using data from a population-based Finnish twin study, the authors document strong moderating effects of socioregional environments on genetic and environmental influences on adolescent alcohol use, with nearly a five-fold difference in the magnitude of genetic effects between environmental extremes. The incorporation of specific environmental measures into genetically informative designs should prove to be a powerful method for better understanding the nature of gene-environment interaction and its contribution to the etiology of behavioral variation.     

The Separation of ADHD Inattention and Hyperactivity-Impulsivity Symptoms: Pathways from Genetic Effects to Cognitive Impairments and Symptoms

Both shared and unique genetic risk factors underlie the two symptom domains of attention deficit hyperactivity disorder (ADHD): inattention and hyperactivity-impulsivity. The developmental course and relationship to co-occurring disorders differs across the two symptom domains, highlighting the importance of their partially distinct etiologies. Familial cognitive impairment factors have been identified in ADHD, but whether they show specificity in relation to the two ADHD symptom domains remains poorly understood. We aimed to investigate whether different cognitive impairments are genetically linked to the ADHD symptom domains of inattention versus hyperactivity-impulsivity. We conducted multivariate genetic model fitting analyses on ADHD symptom scores and cognitive data, from go/no-go and fast tasks, collected on a population twin sample of 1,312 children aged 7–10. Reaction time variability (RTV) showed substantial genetic overlap with inattention, as observed in an additive genetic correlation of 0.64, compared to an additive genetic correlation of 0.31 with hyperactivity-impulsivity. Commission errors (CE) showed low additive genetic correlations with both hyperactivity-impulsivity and inattention (genetic correlations of 0.17 and 0.11, respectively). The additive genetic correlation between RTV and CE was also low and non-significant at ?0.10, consistent with the etiological separation between the two indices of cognitive impairments. Overall, two key cognitive impairments phenotypically associated with ADHD symptoms, captured by RTV and CE, showed different genetic relationships to the two ADHD symptom domains. The findings extend a previous model of two familial cognitive impairment factors in combined subtype ADHD by separating pathways underlying inattention and hyperactivity-impulsivity symptoms.