Two genes involved in chemical signaling in the brain may help explain why antidepressants increase the risk of suicide in some people, according to a new study.
concerns about antidepressant safety arose a few years ago when studies began to indicate that the drug increased the risk of suicide in some adolescents and children. responsible for UK regulation in 03 prohibited the use of minors in several drugs called selective reuptake inhibitors of serotonin (SSRIs), and in 04 the Food and Drug Administration of the United States concluded that all classes antidepressants must carry a warning about the risk in children, adolescents, and young adults ( science NOW, February 3, 04). Although suicide link is well established, it is not clear how antidepressants trigger suicidal behavior or thoughts in some people.
Seeking to shed light on this issue, a team of researchers led by Francis McMahon of the National Institute of Mental Health (NIMH) in Bethesda, Maryland, looked at 68 genes in 1915 adults with major depression who have been treated with SSRI citalopram. The researchers were looking for genetic variations that might be associated with suicidal thoughts, and they may have hit the jackpot.
The reports of the McMahon team in the October issue of The American Journal of Psychiatry he identified two markers, or short sequences of DNA, in two genes GRIA3 and GRIK2 , which corresponds to a significantly increased risk of suicidal thoughts while taking citalopram. GRIA3 and GRIK2 code for receptors for glutamate, a chemical in the brain involved in learning and memory. A small variation in the DNA marker region of these genes appear to be all that separates those who develop suicidal thoughts while taking the drug to those who do not.
Participants with GRIA3 change was a risk almost doubled develop suicidal thoughts, and participants in the GRIK2 variation showed increased eightfold risk. Participants carrying both markers - an extremely rare phenomenon - showed an increase of 15 times the risk
"The findings suggest some of the tendency to develop this type of response to antidepressants could be genetically determined, and that. could be used in the future to develop genetic tests to identify people who might be at risk, "said McMahon. However, he noted that the work should be replicated and says at this stage we do not know why these particular genetic variations contribute to suicidal thinking in people taking antidepressants.
Elliot Gershon, researcher in psychiatric genetics at the University of Chicago in Illinois, who wrote an accompanying editorial in the study, called the results promising. "They head field in the potential of tailoring treatments to differences in individual genes and new general objectives for the treatment of depression," he said.
Related Sites
- The study
- NIMH overview of antidepressants in children
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