Early adversity and 5-HTT/BDNF genes: new evidence of gene-environment interactions on depressive symptoms in a general population.
BACKGROUND
Adverse childhood experiences have been described as one of the major environmental risk factors for depressive disorder. Similarly, the deleterious impact of early traumatic experiences on depression seems to be moderated by individual genetic variability. Serotonin transporter (5-HTT) and brain-derived neurotrophic factor (BDNF) modulate the effect of childhood adversity on adult depression, although inconsistencies across studies have been found. Moreover, the gene x environment (GxE) interaction concerning the different types of childhood adversity remains poorly understood. The aim of this study was to analyse the putative interaction between the 5-HTT gene (5-HTTLPR polymorphism), the BDNF gene (Val66Met polymorphism) and childhood adversity in accounting for adult depressive symptoms.


METHODS
A sample of 534 healthy individuals filled in self-report questionnaires of depressive symptomatology [the Symptom Check List 90 Revised (SCL-90-R)] and different types of childhood adversities [the Childhood Trauma Questionnaire (CTQ)]. The 5-HTTLPR polymorphism (5-HTT gene) and the Val66Met polymorphism (BDNF gene) were genotyped in the whole sample.


RESULTS
Total childhood adversity (beta=0.27, p<0.001), childhood sexual abuse (CSA; beta=0.17, p<0.001), childhood emotional abuse (beta=0.27, p<0.001) and childhood emotional neglect (beta=0.22, p<0.001) had an impact on adult depressive symptoms. CSA had a greater impact on depressive symptoms in Met allele carriers of the BDNF gene than in the Val/Val group (F=5.87, p<0.0001), and in S carriers of the 5-HTTLPR polymorphism (5-HTT gene) (F=5.80, p<0.0001).


CONCLUSIONS
Childhood adversity per se predicted higher levels of adult depressive symptoms. In addition, BDNF Val66Met and 5-HTTLPR polymorphisms seemed to moderate the effect of CSA on adult depressive symptoms.
Aguilera
M
M
Unitat d'Antropologia, Departament Biologia Animal, Facultat de Biologia, Universitat de Barcelona and CIBER de Salud Mental, Instituto de Salud Carlos III, Spain.
Arias
B
B
Wichers
M
M
Barrantes-Vidal
N
N
Moya
J
J
Villa
H
H
van Os
J
J
Ibáñez
M I
MI
Ruipérez
M A
MA
Ortet
G
G
Fañanás
L
L
D000293:Adolescent; D000328:Adult; D000483:Alleles; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D002648:Child; D002649:Child Abuse / Q000523:psychology; D003866:Depressive Disorder / Q000235:genetics* / Q000523:psychology; D004843:Epistasis, Genetic / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006801:Humans; D008016:Life Change Events; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000235:genetics*; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D012931:Social Environment
D019208:Brain-Derived Neurotrophic Factor; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins