DRD4基因与亲社会行为的关联及其潜在脑机制

DRD4基因是亲社会行为的重要候选基因,且与环境交互影响亲社会行为的发生发展。通过梳理既有研究,本文从性别差异、亲社会行为的不同类型及发展动态性等角度探讨了亲社会行为遗传研究存在分歧的原因,并在此基础上探索了DRD4基因作用于亲社会行为的潜在脑机制。未来研究应采用纵向设计探究DRD4基因影响亲社会行为的发展动态性问题,并深入探索其性别差异;采用多质多法分析考察不同类型亲社会行为遗传机制的差异性;采用影像遗传学设计揭示“DRD4基因—脑—亲社会行为”作用机制。     

Transactional models between personality and alcohol involvement: a further examination

Although correlated changes between personality and alcohol involvement have been shown, the functional relation between these constructs is also of theoretical and clinical interest. Using bivariate latent difference score models, we examined transactional relations (i.e., personality predicting changes in alcohol involvement, which in turn predicts changes in personality) across two distinct but overlapping developmental time frames (i.e., across college and during young adulthood) using two large, prospective samples. Across college, there was some evidence that alcohol involvement predicted changes in personality; however, these findings were limited to models that included more proximal measures of alcohol use. When examined across a longer timeframe, we found no evidence that alcohol involvement significantly predicted changes in personality but found some evidence that personality predicted changes in alcohol use. We did find reliable evidence of correlated changes between personality and alcohol use, especially during emerging adulthood. The findings from our datasets highlight that the impact of alcohol involvement on personality change may be limited to shorter intervals during specific developmental time-frames and that the relation between changes in personality and alcohol involvement may be best viewed from a noncausal perspective.     

The DRD4 VNTR polymorphism moderates craving after alcohol consumption.

Recent research has suggested that alterations in mesolimbic dopamine neurotransmission are central to the development and expression of craving for alcohol. Because the D4 dopamine receptor gene, variable numbers of tandem repeats (DRD4 VNTR) polymorphism putatively expresses functional differences in dopamine receptors, the present study tested whether this polymorphism influences the effects of a priming dose of alcohol on craving. Participants consumed 3 alcoholic drinks or 3 control drinks and completed measures of craving after each drink. Participants who were homozygous or heterozygous for the 7 (or longer) repeat allele were classified as DRD4 L, whereas the other participants were classified as DRD4 S. Results suggested that DRD4 L participants demonstrated significantly higher craving after consumption of alcohol as compared with the control beverage.     

Linking Gene, Brain, and Behavior: DRD4, Frontal Asymmetry, and Temperament

ABSTRACT— Gene-environment interactions involving exogenous environmental factors are known to shape behavior and personality development. Although gene-environment interactions involving endogenous environmental factors are hypothesized to play an equally important role, this conceptual approach has not been empirically applied in the study of early-developing temperament in humans. Here we report evidence for a gene- endo environment (i.e., resting frontal brain electroencephalogram, EEG, asymmetry) interaction in predicting child temperament. The dopamine D4 receptor (DRD4) gene (long allele vs. short allele) moderated the relation between resting frontal EEG asymmetry (left vs. right) at 9 months and temperament at 48 months. Children who exhibited left frontal EEG asymmetry at 9 months and who possessed the DRD4 long allele were significantly more soothable at 48 months than other children. Among children with right frontal EEG asymmetry at 9 months, those with the DRD4 long allele had significantly more difficulties focusing and sustaining attention at 48 months than those with the DRD4 short allele. Resting frontal EEG asymmetry did not influence temperament in the absence of the DRD4 long allele. We discuss how the interaction of genetic and endoenvironmental factors may confer risk and protection for different behavioral styles in children.     

The DRD4 VNTR polymorphism influences reactivity to smoking cues

Recent research has indicated that craving for tobacco can be reliably elicited by exposure to smoking cues, suggesting that cue-elicited craving for tobacco may be a useful phenotype for research on genetic factors related to nicotine dependence. Given the potential role of dopamine in cue-elicited craving, the authors examined whether the DRD4 VNTR polymorphism is associated with cue-elicited craving for tobacco. Participants who were homozygous or heterozygous for the 7 repeat (or longer) allele were classified as DRD4 L, and all other participants were classified as DRD4 S. Participants were exposed to smoking cues before smoking either high-nicotine cigarettes or control cigarettes. Analyses suggested that participants in the L group demonstrated significantly greater craving, more arousal, less positive affect, and more attention to the smoking cues than did the participants in the S group.     

Adversity in adolescence predicts personality trait change from childhood to adulthood

This study examined whether cumulative adversity in adolescence predicted changes in the Big Five traits from childhood to adulthood in the Project Competence Longitudinal Study sample (N = 205) followed from childhood (age 10) through adolescence into adulthood (age 30). Personality traits were measured in childhood through multiple methods and in adulthood by self-report. Cumulative adversity, assessed in adolescence, differentiated independent adversity (likely unrelated to participants’ behavior) from dependent adversity (resulting from participants’ own behavior). Participants’ personality traits were modestly stable over 20 years, although Openness showed greater stability. Independent and dependent adversity predicted increases in Negative Emotionality/Neuroticism, and dependent adversity predicted decreases in Constraint/Conscientiousness and Agreeableness from childhood to adulthood, suggesting that cumulative adversity shapes personality development in young people.     

Risky drinking in college changes as fraternity/sorority affiliation changes: a person-environment perspective.

This study aimed to resolve the direction of the relation between Greek affiliation and substance use by taking advantage of the quasi-experimental nature of change in college fraternity/sorority affiliation. Precollege individual differences and college substance use were examined as a function of time-varying Greek status to characterize self-selection (by which heavy substance users opt into Greek systems) and socialization (by which Greek systems foster heavy substance use). Prospective data on continuously enrolled college students (N=2,376), assessed at precollege and in the first 6 semesters of college, were used. Latent class analysis indicated 4 discrete groups of status: constant Greek members (30%), constant nonmembers (64%), late joiners (2%), and droppers (4%). Random coefficient models demonstrated disaffiliation with Greek systems is associated with decreases in risky drinking and alcohol-conducive environmental factors (peer norms and alcohol availability), whereas affiliation is associated with increases, indicating Greek socialization via sociocognitive and physical environments. Future Greeks differed from nonmembers in diverse individual characteristics and heavier substance use at precollege, suggesting multiple selection paths into Greek systems. Findings suggest a reciprocal relation between Greek environment and individuals in determining the trajectories of college drinking and heterogeneity in drinking as functions of changes in Greek affiliation.     

Bidirectional relations between different forms of prosocial behaviors and substance use among female college student athletes

Bidirectional, longitudinal relations between alcohol and marijuana use and prosocial behaviors in women college student athletes were examined. Participants were 187 female college students (M_age = 19.87 years; 91% White) who completed questionnaires on their use of marijuana and alcohol, and six forms of prosocial behaviors across 6 years (2004–2010). The findings yield overall evidence that earlier marijuana use predicted lower levels of most specific forms of prosocial behaviors for women athletes in later young adulthood. Early expressions of altruistic behaviors predicted less marijuana use in later young adulthood. Expression of public prosocial behaviors early in young adulthood predicted higher levels of hazardous drinking in late young adulthood. These novel findings have important implications for links between prosocial development and substance use in women college athletes.     

Childhood Adversity and Adulthood Subjective Well-Being: Evidence from Japan

In this study, we examined the impact of childhood interpersonal adversity on adulthood subjective well-being (SWB), with a focus on the mediating and moderating effects of social support and socioeconomic status (SES). We concentrated on parental maltreatment (abuse and neglect) and bullying in school as childhood adversity variables and on perceived happiness and self-rated health as adulthood SWB measures. Our empirical analysis was based on micro data from a survey in municipalities in and around the Tokyo metropolitan area (N = 3,292). We obtained four key findings. First, the experience of childhood adversity had a substantial negative impact on adulthood SWB. Second, social support and SES significantly mediated the impact of childhood adversity. Third, however, a large proportion of the impact of childhood adversity remained unexplained by their mediation effects. Fourth, social support and SES did not moderate the impact of childhood adversity. Hence, we can conclude that childhood adversity affects adulthood SWB in a relatively independent manner rather than being substantially mediated or moderated by social support or SES. Accordingly, social policies should aim at reducing incidents of childhood maltreatment and bullying in addition to helping people enhance levels of social support and SES in later life.     

Experimental evidence for differential susceptibility: dopamine D4 receptor polymorphism (DRD4 VNTR) moderates intervention effects on toddlers' externalizing behavior in a randomized controlled trial

In a randomized controlled trial we tested the role of genetic differences in explaining variability in intervention effects on child externalizing behavior. One hundred fifty-seven families with 1- to 3-year-old children screened for their relatively high levels of externalizing behavior participated in a study implementing Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD), with six 1.5-hr intervention sessions focusing on maternal sensitivity and discipline. A moderating role of the dopamine D4 receptor (DRD4) variable-number tandem repeat (VNTR) exon III polymorphism was found: VIPP-SD proved to be effective in decreasing externalizing behavior in children with the DRD4 7-repeat allele, a polymorphism that is associated with motivational and reward mechanisms and Attention Deficit Hyperactivity Disorder (ADHD) in children. VIPP-SD effects were largest in children with the DRD4 7-repeat allele whose parents showed the largest increase in the use of positive discipline. The findings of this first experimental test of (measured) gene by (observed) environment interaction in human development indicate that children may be differentially susceptible to intervention effects depending on genetic differences.     

Beyond family‐level adversities: Exploring the developmental timing of neighborhood disadvantage effects on the brain

A growing literature suggests that adversity is associated with later altered brain function, particularly within the corticolimbic system that supports emotion processing and salience detection (e.g., amygdala, prefrontal cortex [PFC]). Although neighborhood socioeconomic disadvantage has been shown to predict maladaptive behavioral outcomes, particularly for boys, most of the research linking adversity to corticolimbic function has focused on family‐level adversities. Moreover, although animal models and studies of normative brain development suggest that there may be sensitive periods during which adversity exerts stronger effects on corticolimbic development, little prospective evidence exists in humans. Using two low‐income samples of boys (n = 167; n = 77), Census‐derived neighborhood disadvantage during early childhood, but not adolescence, was uniquely associated with greater amygdala, but not PFC, reactivity to ambiguous neutral faces in adolescence and young adulthood. These associations remained after accounting for several family‐level adversities (e.g., low family income, harsh parenting), highlighting the independent and developmentally specific neural effects of the neighborhood context. Furthermore, in both samples, indicators measuring income and poverty status of neighbors were predictive of amygdala function, suggesting that neighborhood economic resources may be critical to brain development.     

Holistic face processing among school children,younger and older adults

While previous studies have mostly examined holistic face processing in childhood and young adulthood, the present study investigated developmental changes of holistic face processing under a lifespan perspective, including older adulthood. Children 5–7 and 9–10 years of age, as well as young and older adults were instructed to assign faces into two categories. The categories were constructed to allow either a holistic categorization according to the overall face similarities or an analytical categorization by focusing on single facial features. The results show an increase in holistic face processing from childhood to young adulthood and a decrease towards older adulthood. Features used for categorization changed from internal to external features with age. Thus, crucial changes of face processing occur beyond young adulthood.     

How our work influences who we are: Testing a theory of vocational and personality development over fifty years

This study examines the developmental influences of occupational environments on personality traits from childhood to adulthood. We test aspects of a theory of vocational and personality development, proposing that traits develop in response to work experience following corresponsive and noncorresponsive mechanisms. We describe these pathways in the context of situations of vocational gravitation and inhabitation. In a sample from the Hawaii personality and health cohort (N = 596), we examined associations of childhood and adulthood personality traits, with occupational environments profiled on the RIASEC model. Mediations tests confirmed that work influenced personality development from childhood to adulthood for Openness/Intellect. We observed multiple reactivity effects of occupation environments on adulthood traits that were not associated with corresponding selection effects.     

The role of parenting and dopamine D4 receptor gene polymorphisms in children's inhibitory control

Temperamental effortful control has important implications for children's development. Although genetic factors and parenting may influence effortful control, few studies have examined interplay between the two in predicting its development. The current study investigated associations between parenting and a facet of children's effortful control, inhibitory control (IC), and whether these associations were moderated by whether children had a 7‐repeat variant of the DRD4 exon III VNTR. A community sample of 409 3‐year‐olds completed behavioural tasks to assess IC, and observational measures of parenting were also collected. Negative parenting was associated with lower child IC. The association between children's IC and positive parenting was moderated by children's DRD4 7‐repeat status, such that children with at least one 7‐repeat allele displayed lower IC than children without this allele when positive parenting was lower. These effects appeared to be primarily influenced by parent support and engagement. Results extend recent findings suggesting that some genetic polymorphisms may increase vulnerability to contextual influences.     

The Dopamine Receptor D4 Gene (<Emphasis Type="Italic">DRD4</Emphasis>) Moderates Family Environmental Effects on ADHD

Attention-Deficit/Hyperactivity Disorder (ADHD) is a prime candidate for exploration of gene-by-environment interaction (i.e., G x E), particularly in relation to dopamine system genes, due to strong evidence that dopamine systems are dysregulated in the disorder. Using a G x E design, we examined whether the DRD4 promoter 120-bp tandem repeat polymorphism, previously associated with ADHD, moderated the effects of inconsistent parenting and marital conflict on ADHD or Oppositional-Defiant Disorder (ODD). Participants were 548 children with ADHD and non-ADHD comparison children and their parents. Homozygosity for the DRD4 promoter 120-bp tandem repeat insertion allele increased vulnerability for ADHD and ODD only in the presence of inconsistent parenting and appeared to increase susceptibility to the influence of increased child self-blame for marital conflict on ADHD inattention. DRD4 genotypes may interact with these proximal family environmental risk factors by increasing the individual’s responsivity to environmental contingencies.     

Sociocultural factors, resilience, and coping: Support for a culturally sensitive measure of resilience

This investigation presents 1) a literature review concerning how adversity and resilience influence the development of youth from diverse cultural backgrounds; 2) an examination of measures of resilience with regard to cultural factors that relate to the nature of coping and resilience among young adults from diverse racial/ethnic backgrounds; and 3) the exploration of aspects of cultural resilience: childhood stressors, global coping, adaptive coping, maladaptive coping, and sociocultural support. Results for 305 college age women indicated that cultural factors were related to measures of these five aspects of resilience. Childhood stressors were experienced differentially by individuals from different racial/ethnic and social class status backgrounds, supporting proposals that ecological aspects, notably cultural background and experiences, influence the development of resilience. A conceptual framework illustrating how culture contributes to resilience and coping is presented. Implications for the development of a measure of cultural resilience and its usefulness for developmental community interventions are discussed.     

Multiple protective and risk factors for drug use and abuse: cross-sectional and prospective findings.

A conceptual elaboration was developed that incorporates many risk and protective factors, and both direct and moderating (buffering) influences on drug involvement were tested. From prospective data, 14 factors related to drug use were selected and assigned empirically to either a multiple protective index (PFI) or a risk factor index (RFI). Analyses examined the relationships of the RFI, PFI, and their interaction on measures of cigarette, alcohol, cannabis, cocaine, and hard drug use cross-sectionally in late adolescence and later in young adulthood. These same variables were used to predict alcohol, cannabis, and cocaine abuse 8 years later. Vulnerability as measured by the RFI, PFI, and their interaction was highly associated with drug use in adolescence, moderately associated with certain types of drug use in young adulthood, and strongly associated with heightened drug problems in adulthood.     

Models of developmental regulation in emerging adulthood and links to symptomatology

This contribution deals with theoretical conceptualizations and empirical research analyzing young adults' activity in reaching normative developmental goals in emerging adulthood. It explores whether establishing a stable relationship, starting a career, and achieving residential independence are still important developmental goals now as compared to earlier decades, and how emerging adults strive to achieve them. Findings, based on a longitudinal study of 146 German emerging adults, support the model of adjustment, with developmental goals being adjusted to changes in attainment. Finally, our findings indicate that focusing, selecting, and sequencing of developmental goals during emerging adulthood is adaptive for a healthy transition.     

Course of Antisocial Behavior during Emerging Adulthood: Developmental Differences in Personality

Despite similar normative changes in antisocial behavior (AB) and traits of disinhibition and negative emotionality during "emerging adulthood," few studies have tested if there are developmental differences in personality over this period for distinct courses of AB. In a college cohort assessed at ages 18 and 25, we examined if mean-level changes on traits from the Tridimensional Personality Questionnaire varied by course of AB. Compared to persisters, those who desisted in AB from 18 to 25 exhibited a larger decrease on novelty seeking and larger increase on reward dependence. A significant mean-level decline was observed for harm avoidance, but was unrelated to AB course. Findings support theories of the co-development of personality and AB during emerging adulthood.     

Associate Area Editor's Note

Articles on "Identity and Emerging Adulthood" can include any identity-related topic that pertains to people in the 18-29 age period. I prefer the term emerging adulthood to "youth," "young adulthood," or "the transition to adulthood" because emerging adulthood is a term that has been more clearly defined in its developmental meaning. Emerging adulthood has been conceptualized as a period marked by exploration and instability, and these characteristics certainly pertain to identity issues. The explorations of emerging adulthood are often identity-related, in that they tend to concern love, work, or ideology. The instability of emerging adulthood is a reflection of the changes young people make in the course of their identity explorations. Although identity has traditionally been regarded as a topic that especially pertains to adolescence, today in industrialized societies identity explorations tend to continue into emerging adulthood and in fact become more systematic and serious than in adolescence. Articles submitted to Identity that concern the emerging adulthood period should have a developmental context, not necessarily in line with previous ideas about emerging adulthood but reflecting a consideration of how the developmental characteristics of emerging adulthood may be similar to or different from adolescence or (later) adulthood. For more information about emerging adulthood, see Arnett (2000) in American Psychologist and the web site <http://www.s-r-a.org/easig.html>.