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The interacting effect of the BDNF Val66Met polymorphism and stressful life events on adolescent depression is not an artifact of gene–environment correlation: evidence from a longitudinal twin study
Author(s) -
Chen Jie,
Li Xinying,
McGue Matt
Publication year - 2013
Publication title -
journal of child psychology and psychiatry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.652
H-Index - 211
eISSN - 1469-7610
pISSN - 0021-9630
DOI - 10.1111/jcpp.12099
Subject(s) - psychology , confounding , psychopathology , depression (economics) , heritability , gene–environment interaction , genotype , longitudinal study , medicine , correlation , polymorphism (computer science) , allele , clinical psychology , oncology , gene , genetics , biology , economics , macroeconomics , geometry , mathematics , pathology
Background Confounding introduced by gene–environment correlation ( rGE ) may prevent one from observing a true gene–environment interaction (G × E) effect on psychopathology. The present study investigated the interacting effect of the BDNF Val66Met polymorphism and stressful life events (SLEs) on adolescent depression while controlling for the r GE by two means: separating pure environmental factors (independent SLEs) from the environmental factors under partial genetic control (dependent SLEs) and adopting a prospective longitudinal design. Methods A total of 780 pairs of Chinese twins, aged 11–17 years (mean = 13.6, SD = 1.8) at intake, were followed up twice. Self‐reported depression symptoms at Time 1 and Time 2 were assessed by the Children's Depression Inventory ( CDI ). SLE s occurring between Time 1 and Time 2 were assessed by a self‐reported checklist. SLE s were differentiated into independent and dependent ones and were validated by heritability analyses using twin design. The interacting effects between the BDNF Val66Met polymorphism and numbers of SLE s (total SLE s and independent SLE s) on intraindividual change of depression symptoms were examined. Results After controlling for sex, age, age square, and Time 1 depression, both total SLE s × BDNF Val66Met genotype and independent SLE s × BDNF Val66Met genotype significantly predicted Time 2 depression. Val allele carriers (Val/Val and Val/Met) were more susceptible to the detrimental effects of stress. Conclusions There is a true G × E effect underlying the observed interaction between BDNF Val66Met polymorphism and environmental stress on depression.