NEW YORK - A loving,
supportive family can be enough to override a genetic vulnerability to
depression, new research suggests.
Studies have found that people who carry a "short" version of the serotonin
transporter gene -- known as 5-HTTLPR -- tend to be more susceptible to
depression than people without this gene variant.
But the new findings, published in the journal Biological Psychiatry, show
that to be true only of gene carriers who grew up in a stressful home
environment. In contrast, the investigators found that young adult gene carriers
whose families were warm and supportive had a reduced risk of depression.
The findings point to the importance of nurture, and not only nature, in the
development of depression, according to the study authors.
"A strong family life can be enough to reverse the effects of this risk
factor," lead author Dr. Shelley E. Taylor, a professor of psychology at the
University of California, Los Angeles, told Reuters Health.
On the other hand, a dysfunctional family life may create the stress that
sends genetically vulnerable people into depression, the study findings suggest.
Of the 118 young adults in the study, 27 percent carried two copies of the
short form of 5-HTTLPR. A similar percentage had two "long" versions of the
gene, while the rest carried one copy of each version.
In general, Taylor's team found, men and women who carried two short forms of
the gene had a higher risk of depression than those with the other gene
profiles, but only when they reported a dysfunctional family life -- marked by
conflict, hostility and emotional coldness.
On the other hand, among study participants who said they grew up with a
warm, nurturing family, carriers of two copies of the short gene variant had a
lower risk of depression.
This suggests that the short form of 5-HTTLPR is "highly responsive to
environmental influence," the researchers point out.
Importantly, none of the study participants who grew up in dysfunctional
families reported physical or sexual abuse. Instead, the problems were milder,
including "moderate" degrees of conflict and unaffectionate or "distant"
relationships among family members.
The implication is that even relatively mild family dysfunction can raise a
vulnerable young person's risk of depression.
Still, people with a family history of depression should know that "genes are
not destiny," according to the study authors. Having a "strong support system
that can see you through the tough times," Taylor said, may make the difference.
SOURCE: Biological Psychiatry, October 2006.
