Stress, Depression Have No Link With Genes – Study
By Chioma Umeha
A recent study published in PLOS One led by
Washington University School of Medicine in St. Louis has dismissed the result
of an influential 2003 study about the interaction of genes, environment and
depression.
The new study said that the 2003 study “may have
missed the mark.”
Since publication of the study in Science, that
original paper has been cited by other researchers more than 4,000 times, and
some 100 other studies have been published about links between a
serotonin-related gene, stressful life events and depression risk.
It indicated that people with a particular variant
of the serotonin transporter gene were not as well-equipped to deal with
stressful life events and, when encountering significant stress, were more
likely to develop depression.
Such conclusions were widely accepted, mainly
because antidepressant drugs called selective serotonin reuptake inhibitors
(SSRIs) help relieve depression for a significant percentage of clinically depressed
individuals, so many researchers thought it logical that differences in a gene
affecting serotonin might be linked to depression risk.
But in this new study, the Washington University
researchers looked again at data from the many studies that delved into the
issue since the original publication in 2003, analyzing information from more
than 40,000 people, and found that the previously reported connection between
the serotonin gene, depression and stress wasn’t evident.
The new results are published on Tuesday, in the
journal Molecular Psychiatry.
“Our goal was to get everyone who had gathered
data about this relationship to come together and take another look, with each
research team using the same tools to analyze data the same way,” said the study’s
first author, Robert C. Culverhouse, PhD, an assistant professor of medicine
and of biostatistics. “We all ran exactly the same statistical analyses, and
after combining all the results, we found no evidence that this gene alters the
impact stress has on depression.”
Over the years, dozens of research groups had
studied DNA and life experiences involving stress and depression in the more
than 40,000 people revisited in this study. Some previous research indicated
that those with the gene variant were more likely to develop depression when
stressed, while others didn’t see a connection. So for almost two decades,
scientists have debated the issue, and thousands of hours of research have been
conducted. By getting all these groups to work together to reanalyze the data,
this study should put the questions to rest, according to the researchers.
“The idea that differences in the serotonin gene
could make people more prone to depression when stressed was a very reasonable
hypothesis,” said senior investigator Laura Jean Bierut, MD, the Alumni Endowed
Professor of Psychiatry at Washington University.”
But when all of the groups came together and
looked at the data the same way, we came to a consensus. We still know that
stress is related to depression, and we know that genetics is related to
depression, but we now know that this particular gene is not.”
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