Association Between Parent-adolescent Relationship And Adolescents' Social Adjustments: The Effect Of Gene And Environment

A wealthy of previous study has shown that there is a robust association between parent-adolescent relationship and adolescents'social adjustments. However, the mechanism underlying the association has remained unclear. Psychosocial designs have often concluded that parent-adolescent relationship causes or exacerbates adolescents externalizing or internalizing problems. Although the qualitative behavior genetics by adopting a twin-study design and an adopt-study design has found that parent-adolescent relationship and adolescents'social adjustments is associated by an overlap in genetic effects or by an overlap in environmental factors, such insights have traditionally been based on decomposing variance in a given phenotype without actually measuring the nature of the genetic and environmental factors, therefore the documented links between parent-adolescent relationship and adolescents'social adjustments leave open the question of whether genetic and environmental effects underlie the relationship. With the advancement of molecular genetics, it is possible to systematically explore the effect of gene and environment on the associtation between parent-adolescent relationship and adolescents'social adjustments in recent years. A large number of research in the discipline of psychopathology, pharmacology, and epidemiology have examined the genetic influences on the the major depression, dipolar I disorder, ADHD or the aggression of patient with schizophrenia, and got some valuable findings. However, to date, little attempts has been made with the sample of healthy adolescents in the discipline of developmental psychology, and the underlying mechanism of genetic and environmental influences on the association between parent-adolescent relatiship and adolescents'social adjustments still remain unclear.This doctoral thesis was to examine the genetic and environmental influences on the association between parent-adolescent relatiship and adolescents'social adjustments in the group of healthy adolescents with a corss-sectional design and by a synthesized method of psychosocial analysis and genetical design from the perspective of developmental psychology. Specifically, (1) examing the associtation between parent-adolescent relatiship and adolescents'social adjustments with a psychosocial design; (2) examing the association between parent-adolescent relatiship and adolescents'social adjustments with a molecular genetics design, which consists of three parts: (I) examing the genetic and environmental influences on the adolescents'social adjustments; (II) examing the genetic and environmental influences on the parent-adolescent relationship; (III) examing the genetic and environmental influences on the association between the parent-adolescent relationship and adolescents'social adjustments. Three steps were taken to carry out the present study. Firstly, the aggression subscale of Youth Self-Report ( YSR;α= 0.82), Center for Epidemiologic Studies Depression Scale (CES-D;α= 0.87), a series of qustionnaires of parent-adolescent relationship (α= 0.73-0.93), and Adolescent Life Event Scale (α= 0.91) were administered to 715 participants. Secondly, those scored on the top 10% and at the bottom10% of aggression or depression were chosen to constitute high and low aggression or depression group, and then teacher rated whether the grouping was in accordance with his or her observation, if no, the related participant was eliminated. Finally, DNA collection from saliva were performed on the 208 seleted adolescents (high aggression group: n = 65, low aggression group: n = 88; high depression group: n = 59, low depression group: n = 68), and 14 candidate SNP was genotyped using the MassARRAY Typer software version 3.4 (Sequenom).Analyses were carried out using SPSS17.0,SHEsis and MPLUS 5.2, and the main findings were as follows:1. Parent -adolescent relationship was significantly correlated with adolescents'social adjustments (aggression and depression ).2. The development of the healthy adolescents'social adjustments had genetic and environmental underpinning, which independently and coordinately influence adolescents'social adjustments. The pathway from gene to adolescents'social adjustments was complicated, on the one hand one specific candidate gene imposes its unique effect, and on the other hand its effect was moderated by other genes, adolescents'gender or negative life events.3. Parent-adolescent relationship had genetic and environmental underpinning. A single candidate gene had no significantly effect on the parent-adolescent relationship, however, it interacted with other genes, adolescents'gender or negative life events.4. The association between parent-adolescent relationship and adolescents'social adjustments was moderated by the gene and environment. When the the genetic and environmental influences were controlled the association decreased significantly, especially for the association between parent-adolescent violent conflict and adolescents'social adjustments.5. There existed various pathways from genetic and environmental influences to parent-adolescent relationship and adolescents'social adjustments. On the one hand, gene and/or negative life events imposed direct and independent influences on parent-adolescent relationship and adolescents'social adjustments, and on the other hand, they imposed indirect effects on adolescents'social adjustments through parent-adolescent relationship, that is, parent-adolescent relationship mediated the association between gene and adolescents'social adjustments.The research in this dissertation provides evidence that parent-adolescent relationship and adolescents'social adjustments were influenced by gene and environment, and it captures the underlying mechanisms, which contriutes to deepen the existing recognitions about parent-adolescent relationship and adolescents'social adjustments, and can be used as references to promte adolescents'positive development. In addition, this dissertation indicates that it is necessary and possible for scholars in the discipline of the developmental psychology to examine the normal adolescents'development using the techonolgy of molecular genetics and in accordance with the developmental systematic perspectives.