title: Plasticity genes do not modify associations between physical activity and depressive symptoms.
abstract: OBJECTIVE
  Physical activity is inversely associated with depression in adolescents, but the overall associations are fairly weak, suggesting individual differences in the strength of the associations. The aim of this study was to investigate whether plasticity genes modify the reciprocal prospective associations between physical activity and depressive symptoms found previously.
  
  
  METHODS
  In a prospective population-based study (N = 1,196), physical activity and depressive symptoms were assessed three times, around the ages of 11, 13.5, and 16. Structural Equation Modeling was used to examine reciprocal effects of physical activity and depressive symptoms over time. The plasticity genes examined were 5-HTTLPR, DRD2, DRD4, MAOA, TPH1, 5-HTR2A, COMT, and BDNF. A cumulative gene plasticity index consisting of three groups (low, intermediate, and high) according to the number of plasticity alleles carried by the adolescents was created. Using a multigroup approach, we examined whether the associations between physical activity and depressive symptoms differed between the three cumulative plasticity groups, as well as between the individual polymorphisms.
  
  
  RESULTS
  We found significant cross-sectional and cross-lagged paths from physical activity to depressive symptoms and vice versa. Neither the cumulative plasticity index nor the individual polymorphisms modified the strengths of these associations.
  
  
  CONCLUSIONS
  Associations between adolescents' physical activity and depressive symptoms are not modified by plasticity genes.
authors.affiliation: Interdisciplinary Centre for Psychopathology and Emotion Regulation (ICPE), University Medical Centre Groningen (UMCG), Groningen, The Netherlands. n.stavrakakis@umcg.nl
authors.forename: N
authors.initials: N
authors.lastname: Stavrakakis
authors.forename: A J
authors.initials: AJ
authors.lastname: Oldehinkel
authors.forename: E
authors.initials: E
authors.lastname: Nederhof
authors.forename: R C
authors.initials: RC
authors.lastname: Oude Voshaar
authors.forename: F C
authors.initials: FC
authors.lastname: Verhulst
authors.forename: J
authors.initials: J
authors.lastname: Ormel
authors.forename: P
authors.initials: P
authors.lastname: de Jonge
mesh_terms: D000293:Adolescent; D000483:Alleles; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics; D002394:Catechol O-Methyltransferase / Q000235:genetics; D002648:Child; D003430:Cross-Sectional Studies; D003863:Depression / Q000235:genetics* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008995:Monoamine Oxidase / Q000235:genetics; D009043:Motor Activity / Q000235:genetics*; D009473:Neuronal Plasticity / Q000235:genetics*; D011110:Polymorphism, Genetic; D011446:Prospective Studies; D044402:Receptor, Serotonin, 5-HT2A / Q000235:genetics; D017448:Receptors, Dopamine D2 / Q000235:genetics; D050638:Receptors, Dopamine D4 / Q000235:genetics; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics; D014365:Tryptophan Hydroxylase / Q000235:genetics
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C581293:DRD2 protein, human; C493599:DRD4 protein, human; D044402:Receptor, Serotonin, 5-HT2A; D017448:Receptors, Dopamine D2; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D050638:Receptors, Dopamine D4; C579455:BDNF protein, human; C497467:TPH1 protein, human; D014365:Tryptophan Hydroxylase; D008995:Monoamine Oxidase; C579458:monoamine oxidase A, human; D002394:Catechol O-Methyltransferase