title: BDNF Met66 modulates the cumulative effect of psychosocial childhood adversities on major depression in adolescents.
abstract: BACKGROUND
  The interplay among lifetime adversities and the genetic background has been previously examined on a variety of measures of depression; however, only few studies have focused on major depression disorder (MDD) in adolescence.
  
  
  METHODS
  Using clinical data and DNA samples from mouthwash gathered from an epidemiological study on the prevalence of mental disorders in youths between 12 and 17 years old, we tested the statistical interaction between a set of psychosocial adversities experienced during childhood (CAs) with two common polymorphisms in the brain-derived neurotrophic factor (BDNF) (Val66Met) and SLC6A4 (L/S) genes on the probability of suffering MDD in adolescence.
  
  
  RESULTS
  Genotype or allele frequencies for both polymorphisms were similar between groups of comparison (MDD N = 246; controls N = 270). The CAs factors: Abuse, neglect, and family dysfunctions; parental maladjustment, parental death, and to have experienced a life-threatening physical illness were predictors of clinical depression in adolescents. Remarkably, the cumulative number of psychosocial adversities was distinctly associated with an increase in the prevalence of depression but only in those Val/Val BDNF individuals; while the possession of at least a copy of the BDNF Met allele (i.e., Met +) was statistically linked with a "refractory" or resilient phenotype to the noticeable influence of CAs.
  
  
  CONCLUSIONS
  Liability or resilience to develop MDD in adolescence is dependent of a complex interplay between particular environmental exposures and a set of plasticity genes including BDNF. A better understanding of these factors is important for developing better prevention and early intervention measures.
authors.affiliation: Psychiatric Genetics Department, Clinical Research Branch, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñíz" Mexico City, México.
authors.forename: Carlos S
authors.initials: CS
authors.lastname: Cruz-Fuentes
authors.affiliation: Epidemiology and Psychosocial Research Division, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñíz" Mexico City, México.
authors.forename: Corina
authors.initials: C
authors.lastname: Benjet
authors.affiliation: Psychiatric Genetics Department, Clinical Research Branch, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñíz" Mexico City, México.
authors.forename: Gabriela A
authors.initials: GA
authors.lastname: Martínez-Levy
authors.affiliation: Psychiatric Genetics Department, Clinical Research Branch, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñíz" Mexico City, México.
authors.forename: Amado
authors.initials: A
authors.lastname: Pérez-Molina
authors.affiliation: Psychiatric Genetics Department, Clinical Research Branch, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñíz" Mexico City, México.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Briones-Velasco
authors.affiliation: Psychiatric Genetics Department, Clinical Research Branch, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñíz" Mexico City, México.
authors.forename: Jesús
authors.initials: J
authors.lastname: Suárez-González
mesh_terms: D000293:Adolescent; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D002648:Child; D002649:Child Abuse; D003865:Major Depressive Disorder / Q000209:etiology* / Q000235:genetics*; D005260:Female; D059647:Gene-Environment Interaction; D006801:Humans; D008016:Life Change Events; D008297:Male; D055500:Resilience, Psychological; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins
keywords: Adolescence; Mexican; brain-derived neurotrophic factor gene; childhood adversities; major depression; serotonin transporter gene