The Effect Of MAOA,5-HTT Polymorphism And Parenting On Children’s Social Adjustment

As a key aspect of child development, child social adjustment has won more and more attention. Genetic (G) and environmental factors (E) play a critical role in the development of child social adjustment. How G and E interact with each other is a hot topic in the field of child development. It is theoretically predicted that the nature of G X E interaction is possibly presented as genetic vulnerability, differential susceptibility, the goodness of fit and social enhancement models. However, few empirical studies systematically explored the nature of G×E interaction. Therefore, the present study aimed to explore how and when MAOA/5-HTTLPR polymorphism and parenting interacted with each other when impacting on chilld social adjustment in China.416 children and their parents participated in this study. When children were 6 months old, both the mother and father reported their own parenting stress and cognitive involvement. Buccal cells from children and demographic data were also collected. MAOA and 5-HTTLPR genotypes were determined by polymerase chain reaction amplification At 24 months, a series of questionnaires concerning parenting styles, child behavioral problems and social competence were rated by parents. Additionally, maternal low power of control strategies was coded by observing mother-child free play interaction.2 years later, parents were invited again to report child behavioral problems and social competence. The regression analysis, simple slope analysis and "regions of significance" approach were performed to probe the natur of the interactions. The results were expressed as follow:Firstly, maternal parenting stress and overprotection positively predicted internalizing problems of preschool boys with low-activity allele, but not for boys with high-activity allele. These interactions were consistent with genetic vulnerability model. It indicated that the low-activity genotype is a risk factor for preschool boy’s internalizing problems at preschool age if maternal parenting stress and overprotection were high.Secondly, paternal harsh parenting was positively associated with high-activity boys’ externalizing and internalizing problems at preschool age, but not for low-activity boys. This interaction between MAOA genotype and paternal harsh parenting was consistent with social enhancement model. It indicated that the high-activity genotype is a "vantage susceptible" factor for preschool boys to profit most from positive parenting.Thirdly, maternal harsh parenting negatively predicted high-activity boys’ social competence, but not for low-activity boys at toddlerhood. Additionally, maternal cognitive involvement positively predicted low-activity boys’ social competence, but not for high-activity boys at preschool age. The former interaction was in line with social enhancement model and the later was fit with genetic vulnerability model. It indicated that the high-activity genotype is a vantage susceptible factor for boy’s social competence at toddlerhood if maternal harsh parenting is low, but the low-activity genotype is a risk factor for preschool boys’ social competence if maternal cognitive involvement is low.Fourthly, maternal harsh parenting positively predicted externalizing and internalizing problems of preschool girls with high-activity genotype. Maternal cognitive involvement positively predicted high-activity girls’ social competence, but not for low-activity girls at preschool age. These interactions were in keeping with genetic vulnerability model, which indicated that the high-activity genotype is a risk factor for preschool girls’ social adjustment under maternal negative parenting.Fifthly, paternal parenting stress was positively associated with externalizing problems of preschoolers with s/s and s/1 genotypes, but not for preschoolers with 1/1 genotype. This interaction was satisfied with social enhancement model, which indicated that s/s and s/1 genotypes were vantage susceptible factors for preschoolers to have low externalizing problems under low parenting stress.Sixthly, maternal parenting stress was positively linked with externalizing problems of boys with s/s and s/1 genotypes, but not for boys with 1/1 genotype. Maternal harsh parenting was positively associated with internalizing problems of boys with s/s and s/1 genotypes, but not for boys with 1/1 genotype. These interactions consisted with social enhancement model, which indicated that the s/s and s/1 genotypes were vantage susceptible factors for preschool boys to have low behavioral problems under low maternal parenting stress or low harsh parenting.Seventhly, maternal parenting stress was positively associated with internalizing problems of preschool girls with 1/1 genotype, but not for girls with s/s and s/1 genotypes. This interaction fit with genetic vulnerability model, which indicated that the 1/1 genotype is a risk factor for preschool girls to suffer from high maternal parenting stress.Finally, paternal parenting stress was positively associated with social competence of toddlers with 1/1 genotype, but not for toddlers with s/s and s/1 genotypes. Maternal overprotection negatively predicted social competence of preschoolers carrying s/s and s/1 genotypes, but not for/’/-genotype preschoolers. The former interaction was in line with genetic vulnerability model, but the later conformed to social enhancement model. It indicated that the s/s and s/1 genotypes were vantage susceptible factors for preschoolers’social competence to benefit from low level of maternal overprotection, but 1/1 genotype is a risk for toddlers to have low social competence if the father was in high parenting stress.In summary, the present study provided evidence for the notion that the interactions of parenting with MAOA or 5-HTTLPR polymorphism were in line with genetic vulnerability and social enhancement models. It demonstrated that the preschool age is the sensitive period of the G×E interactions in child social adjustment.