The risk of posttraumatic stress disorder after trauma depends on traumatic load and the catechol-o-methyltransferase Val(158)Met polymorphism.
BACKGROUND
The risk for posttraumatic stress disorder (PTSD) depends on the number of traumatic event types experienced in a dose-response relationship, but genetic factors are known to also influence the risk of PTSD. The catechol-O-methyltransferase (COMT) Val158Met polymorphism has been found to affect fear extinction and might play a role in the etiology of anxiety disorders.


METHODS
Traumatic load and lifetime and current diagnosis of PTSD and COMT genotype were assessed in a sample of 424 survivors of the Rwandan Genocide living in the Nakivale refugee camp in southwestern Uganda.


RESULTS
Higher numbers of different lifetime traumatic event types led to a higher prevalence of lifetime PTSD in a dose-response relationship. However, this effect was modulated by the COMT genotype: whereas Val allele carriers showed the typical dose-response relationship, Met/Met homozygotes exhibited a high risk for PTSD independently of the severity of traumatic load.


CONCLUSIONS
The present findings indicate a gene-environment interaction between the human COMT Val158Met polymorphism and the number of traumatic event types experienced in the risk of developing PTSD.
Kolassa
Iris-Tatjana
IT
University of Konstanz, Germany. Iris.Kolassa@uni-konstanz.de
Kolassa
Stephan
S
Ertl
Verena
V
Papassotiropoulos
Andreas
A
De Quervain
Dominique J-F
DJ
D000293:Adolescent; D000328:Adult; D000349:Africa; D000368:Aged; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D016009:Chi-Square Distribution; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008016:Life Change Events; D008297:Male; D008715:Methionine / Q000235:genetics*; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011336:Probability; D012307:Risk Factors; D013313:Stress Disorders, Post-Traumatic / Q000235:genetics*; D014633:Valine / Q000235:genetics*; D055815:Young Adult
D008715:Methionine; D002394:Catechol O-Methyltransferase; D014633:Valine