Does genetic background moderate the association between parental education and school achievement?

Uncovering the complex genetics of human character

Human personality is 30-60% heritable according to twin and adoption studies. Hundreds of genetic variants are expected to influence its complex development, but few have been identified. We used a machine learning method for genome-wide association studies (GWAS) to uncover complex genotypic-phenotypic networks and environmental interactions. The Temperament and Character Inventory (TCI) measured the self-regulatory components of personality critical for health (i.e., the character traits of self-directedness, cooperativeness, and self-transcendence). In a discovery sample of 2149 healthy Finns, we identified sets of single-nucleotide polymorphisms (SNPs) that cluster within particular individuals (i.e., SNP sets) regardless of phenotype. Second, we identified five clusters of people with distinct profiles of character traits regardless of genotype. Third, we found 42 SNP sets that identified 727 gene loci and were significantly associated with one or more of the character profiles. Each character profile was related to different SNP sets with distinct molecular processes and neuronal functions. Environmental influences measured in childhood and adulthood had small but significant effects. We confirmed the replicability of 95% of the 42 SNP sets in healthy Korean and German samples, as well as their associations with character. The identified SNPs explained nearly all the heritability expected for character in each sample (50 to 58%). We conclude that self-regulatory personality traits are strongly influenced by organized interactions among more than 700 genes despite variable cultures and environments. These gene sets modulate specific molecular processes in brain for intentional goal-setting, self-reflection, empathy, and episodic learning and memory.

Differential susceptibility to effects of maternal sensitivity? A study of candidate plasticity genes

Here we tested whether there was genetic moderation of effects of early maternal sensitivity on social–emotional and cognitive–linguistic development from early childhood onward and whether any detected Gene × Environment interaction effects proved consistent with differential-susceptibility or diathesis–stress models of Person × Environment interaction (N= 695). Two new approaches for evaluating models were employed with 12 candidate genes. Whereas maternal sensitivity proved to be a consistent predictor of child functioning across the primary-school years, candidate genes did not show many main effects, nor did they tend to interact with maternal sensitivity/insensitivity. These findings suggest that the developmental benefits of early sensitive mothering and the costs of insensitive mothering look more similar than different across genetically different children in the current sample. Although acknowledgement of this result is important, it is equally important that the generally null Gene × Environment results reported here not be overgeneralized to other samples, other predictors, other outcomes, and other candidate genes.

Relation of symptom-induced impairment with other illness parameters in clinic-referred youth

OBJECTIVE

To examine the relation of caregiver ratings of psychiatric symptom-induced impairment with number and severity of symptoms and informant agreement in consecutive child psychiatry outpatient referrals.

METHODS

Parents and teachers completed a broadband DSM-IV-referenced rating scale with disorder-specific impairment for 636 youth (6-18 years). Illness parameters included impairment, number and severity of symptoms, and their combination (symptom + impairment) as well as categorical (cut-off) and dimensional scoring.

RESULTS

Agreement between impairment and other illness parameters showed considerable variation as a function of type of parameter, disorder, and informant, but to lesser extent age and gender. Many youth who met impairment cut-off for specific disorders did not meet symptom cut-off. Conversely, most youth who met symptom cut-off were impaired. Symptom cut-off evidenced greater convergence with impairment cut-off than combined symptom + impairment cut-offs. Severity of impairment was moderately to highly correlated with number and severity of symptoms. Parents' and teachers' ratings indicated little disorder-specific agreement about youth who met impairment cut-off, symptom cut-off, or combined symptom + impairment cut-off. Therefore, sole reliance on one informant greatly underestimates the pervasiveness of impairment.

CONCLUSION

Findings are consistent with the notion that each illness parameter represents a unique conceptual construct, which has important clinical and research implications.

Poverty as a predictor of 4-year-olds' executive function: new perspectives on models of differential susceptibility

In a predominantly low-income, population-based longitudinal sample of 1,259 children followed from birth, results suggest that chronic exposure to poverty and the strains of financial hardship were each uniquely predictive of young children's performance on measures of executive functioning. Results suggest that temperament-based vulnerability serves as a statistical moderator of the link between poverty-related risk and children's executive functioning. Implications for models of ecology and biology in shaping the development of children's self-regulation are discussed.

Serotonin receptor 2A gene moderates the effect of childhood maternal nurturance on adulthood social attachment

The ability to form and maintain attachment relations with other people is crucial for mental health and well-being. The origins of attachment behaviors are often assumed to be in early experiences with other people, especially with primary caregivers. Preliminary evidence suggests that serotonergic system may be involved in attachment behaviors. We examined whether the T102C variant of the serotonin receptor 2A gene moderates the effect of childhood maternal nurturance on social attachment in adulthood. The participants were 1070 women and men from the Young Finns Study with 27-year follow-up and two measurement times for the outcomes (n = 1836 person observations). Mothers reported their relationship quality with their children (participants) in childhood or adolescence. Social attachment was assessed by participant's self-reports on two measures (reward dependence scale of the Temperament and Character Inventory and the Relationship Questionnaire). High childhood maternal nurturance predicted high reward dependence and low avoidant attachment in carriers of the T/T genotype but not in the T/C or C/C genotype groups, while low maternal nurturance was associated with low reward dependence and high avoidant attachment in T/T genotype carriers but not in C allele carriers. Our result suggests that T/T genotype carriers were more influenced by their childhood nurturing environment, than their C allele carrying counterparts, thus providing evidence for differential susceptibility to childhood nurturing environment associated with the HTR2A gene.