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October 10, 2006
Early Family Experience Can Eliminate the Effects of Genes, Minimize Risk of Mental Illness
UCLA psychology researchers reported today that a positive, low-stress emotionally healthy family environment for children can eliminate or minimize the effect of a gene variation that is strongly linked to a person's risk for developing depression. The study was published in the current issue of the journal Biological Psychiatry.
While this new research study is focused on depression, a large body of related research suggests that the same effect is true with schizophrenia risk genes (see here and here for details) as well as risk genes for other mental illnesses. This is consistent with the current scientific theory that many disease-associated genes only become active when a person is exposed to a specific type of environmental factor (or factors) that triggers the gene to become active.
In many psychiatric disorders, research is increasingly suggesting that a child may have the genes that predispose them to the disorder - but they will only get the disorder if they experience the environmental factor(s) that turns the gene on. This new research suggests that environmental factors that may greatly increase the risk of depression (for those genetically at risk) may be stressful, emotionally cold, stressful or unsupportive family environments.
This UCLA research study found that among children from supportive, nurturing, low-stress families, those with the short form of the serotonin transporter gene (known as 5-HTTLPR) had a significantly reduced risk for depression. The research was done by a UCLA team, under the direction of Shelley E. Taylor, UCLA distinguished professor of psychology and an expert in the field of stress and health. The research team also found that among children from emotionally cold, unsupportive homes marked by conflict and anger, those with the short form of the 5-HTTLPR gene were at greater risk for depression, as some previous research has also shown.
The 118 young adult men and women who participated in the study completed assessments of depression, early family environment and current stress. They were asked, for example, how often they had been loved and cared for, shown physical affection or insulted and sworn at by their families. Saliva samples were used to determine if the participants' standing on the 5-HTTLPR had two short alleles (s/s), a short and a long allele (s/l) or two long alleles (l/l) for the serotonin transporter gene. (An allele is any of several forms of a gene.)
The research showed that a person's likelihood of developing symptoms of depression was not predicted by the particular combination of gene alleles alone; rather, it was the combination of the person's environment and genetic variant s/s that determined whether the person experienced symptoms of depression, said Taylor, principal investigator on the study.
Among the study's implications is that the short form of the 5-HTTLPR is "highly responsive to environmental influence" and, rather than predicting risk for depression, its effects vary substantially, depending on how supportive the external environment is, Taylor said.
These conclusions were bolstered by parallel evidence collected by the team showing that a supportive environment reduced the risk of depression among those with the s/s form of the 5-HTTLPR gene, while those experiencing a great deal of stress in their lives had an increased risk of depressive symptoms if they had the s/s variant of the gene. "Genes are not destiny," Taylor said. "Although some genes confer particular risks, others, such as variants of the 5-HTTLPR, are clearly highly responsive to input from the early and current environment. That means, among other conclusions, that there is an important role that parents and even friends can play in providing protection against the risk of depression that stress can confer." The study adds a new component to evidence that the environment can regulate biology and steer the effects of genetic predispositions.
"It indicates just how important a loving and caring family can be," said Baldwin Way, a co-investigator on the project. The other members of the research team, from UCLA's department of psychology and department of psychiatry and biobehavioral sciences, are William Welch, Clayton Hilmert, Barbara Lehman and Naomi Eisenberger.
The research was federally funded by the National Institute of Mental Health, and the National Science Foundation, with additional funding from and UCLA's Center for Psychoneuroimmunology.
In previous research, Taylor and UCLA colleagues, including psychology professor Rena Repetti, reported strong evidence that children who grow up in risky families often suffer lifelong health problems, including cancer, heart disease, hypertension, diabetes, obesity, depression and anxiety disorders, as well as early death (Psychological Bulletin, March 2002, Vol. 128, No. 2, pp. 330–366). A child's genetic predispositions may be exacerbated by the family environment, and this combination can lead to the faster development of health problems in risky families, which may be more debilitating than they would be in a more nurturing family, the researchers found.
Source: University of California, Los Angeles (UCLA)
Research Paper: Early family environment, current adversity, the serotonin transporter promoter polymorphism, and depressive symptomatology. Biol Psychiatry. 2006 Oct 1;60(7):671-6.
Recommended Parenting Books - How to Lower the Risk of Mental Illness in Your Children
Nine Excellent articles on Epigenetics (How Parent's Behavior can change the genes of their children) (New York Times, Wall Street Journal, etc.)
Posted by szadmin at October 10, 2006 09:39 AM
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