A study published in the June 17 issue of JAMA,
the Journal of the American Medical Association, contradicts the
findings of a much-celebrated 2003 report, which stated that genetic
variation of the serotonin transporter gene, interacting with stressful
life events, plays a role in predisposition to major depression.
The new study, conducted by Neil Risch, Ph.D., of the University of
California at San Francisco and Kaiser Permanente Northern California
Division of Research, Oakland, and colleagues, identified 14 previous
studies of the gene-environment interaction that met criteria for
inclusion in the analysis. Of a total of 14,250 participants, 1,769
were classified as having depression; 12,481 as not having depression.
The researchers did find that the number of stressful life events is
associated with depression.
While it is generally assumed that psychiatric disorders result from a
combination of genetic vulnerability and environmental exposure, the
authors state that “few if any of the genes identified in candidate
gene association studies of psychiatric disorders have withstood the
test of replication and to date genome-wide association studies of
psychiatric disorders have also had limited success.”
The original study, conducted by Avshalom Caspi, Ph.D., of Duke
University, followed 847 people from birth to age 26 and found that
those most likely to sink into depression after a stressful event had a
particular variant of a gene involved in the regulation of serotonin, a
brain messenger that affects mood.
The new report is provoking intense debate in the psychiatric community
and the public media. NARSAD Distinguished Investigator Myrna Weissman,
Ph.D., professor of epidemiology and psychiatry at Columbia University,
was quoted in the New York Times
as saying that while “this is an excellent review paper, no one is
questioning that,” it ignored extensive evidence from humans and
animals linking excessive sensitivity to stress to the serotonin gene.
The consensus of opinions, including those of Dr. Caspi and the authors
of the new study, was the urgent need for additional research.
(This article was adapted by permission from JAMA, the journal of the American Medical Association.)
