Relationship between the COMT-Val158Met and BDNF-Val66Met polymorphisms, childhood trauma and psychotic experiences in an adolescent general population sample.
OBJECTIVE
Psychotic experiences occur at a much greater prevalence in the population than psychotic disorders. There has been little research to date, however, on genetic risk for this extended psychosis phenotype. We examined whether COMT or BDNF genotypes were associated with psychotic experiences or interacted with childhood trauma in predicting psychotic experiences.


METHODS
Psychiatric interviews and genotyping for COMT-Val158Met and BDNF-Val66Met were carried out on two population-based samples of 237 individuals aged 11-15 years. Logistic regression was used to examine for main effects by genotype and childhood trauma, controlling for important covariates. This was then compared to a model with a term for interaction between genotype and childhood trauma. Where a possible interaction was detected, this was further explored in stratified analyses.


RESULTS
While childhood trauma showed a borderline association with psychotic experiences, COMT-Val158Met and BDNF-Val66Met genotypes were not directly associated with psychotic experiences in the population. Testing for gene x environment interaction was borderline significant in the case of COMT-Val158Met with individuals with the COMT-Val158Met Val-Val genotype, who had been exposed to childhood trauma borderline significantly more likely to report psychotic experiences than those with Val-Met or Met-Met genotypes. There was no similar interaction by BDNF-Val66Met genotype.


CONCLUSIONS
The COMT-Val158Met Val-Val genotype may be a genetic moderator of risk for psychotic experiences in individuals exposed to childhood traumatic experiences.
Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland.
Hugh
H
Ramsay
Ian
I
Kelleher
Padraig
P
Flannery
Mary C
MC
Clarke
Fionnuala
F
Lynch
Michelle
M
Harley
Dearbhla
D
Connor
Carol
C
Fitzpatrick
Derek W
DW
Morris
Mary
M
Cannon
D000293:Adolescent; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D002648:Child; D005260:Female; D059647:Gene-Environment Interaction; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D011618:Psychotic Disorders / Q000201:enzymology / Q000235:genetics* / Q000523:psychology*; D014754:Violence / Q000523:psychology
D019208:Brain-Derived Neurotrophic Factor; D002394:Catechol O-Methyltransferase