Skip to comments.Child abuse leaves lasting 'scars' on DNA - Lingering marks on DNA could amplify stress responses.
Posted on 02/23/2009 1:34:04 AM PST by neverdem
Suicide victims with a history of abuse during childhood are more likely to carry chemical changes to their DNA that could affect how they respond to stress as adults, a study has found.
Those with no history of childhood abuse did not show the same pattern of DNA modification, and had normal expression of NR3C1, a gene linked to stress responses.
But the findings do not mean that the effect of childhood abuse is indelible, cautions Joan Kaufman, a psychologist at Yale School of Medicine in New Haven, Connecticut, who was not involved in the new study. "The long-term effects of early abuse are not inevitable," she says, "and the more you understand about the mechanisms of risk, the more you can devise treatments."
The results, reported today in Nature Neuroscience1, follow on from work showing that rat pups that are stressed because they were raised by negligent mothers have extra methyl groups in their DNA in a region of the genome that controls expression of Nr3c1, the equivalent gene in rats. Such 'methylation' can reduce gene expression. NR3C1 encodes a protein expressed in neurons that responds to hormones called glucocorticoids. Lower expression of NR3C1 could be harmful because reduced responses to these glucocorticoids have been linked to increased stress.
To find out whether the results in rodents translated into humans, neurobiologist Michael Meaney of McGill University in Montreal, Canada, and his colleagues collected brain samples from the Quebec Suicide Brain Bank. The researchers looked at samples from 12 suicide victims with a history of childhood abuse, 12 suicide victims with no history of childhood abuse, and 12 controls who had died suddenly from other causes.
People with a history of childhood abuse had lower levels of glucocorticoid receptors than either people who had not been abused or those who had not committed suicide. And childhood-abuse victims had a similar methylation pattern to that seen in rats that had been stressed as pups.
These changes are unlikely to be passed on to the next generation, notes Meaney. Although researchers have not yet looked for effects on egg or sperm DNA, it is doubtful that the changes affect the germline, he says.
Researchers do not yet know whether trauma as an adult produces the same pattern of changes. There may be times during childhood when the developing brain is particularly responsive to abuse, explains Martin Teicher, director of the Developmental Biopsychiatry Research Program at Harvard Medical School in Belmont, Massachusetts. Teicher and his collaborators imaged the brains of women who had been victims of child abuse and found that those who were abused between the ages of three and five, or eleven and thirteen, had a smaller hippocampus â a region in the brain that is important for memory and learning â than those who had not been abused2.
Studies in rats have also suggested that the methylation changes can be reversed: if pups reared by negligent mothers are later treated with a chemical that removes DNA methylation, their stress responses return to normal3.
Such drugs are not ready for use in humans, and could carry unwanted side effects. But medication may not be the only way to treat victims of child abuse, and DNA methylation was restored to normal in neglected rat pups if those pups were transferred to more attentive mothers. "Just because there's a biological effect doesn't mean the only way you can intervene with drugs," says Kaufman.
Psychotherapy, for instance, has been shown to produce chemical changes in the brain, and might be able to reset the methylation pattern, says Meaney. "A social event got you into it. Could a social event get you back out?", he asks. "That's a very viable hypothesis."
Not at all. Check out Epigenetics at Wiki.
Well if that’s the case,would not every other hiccup & annoyance throughout our lives be changing our DNA too?
Maybe it's epigenetics?
Some of the conclusions might be nuts. However, I've always wondered whether the nervous system has some kind of mechanism to protect the organism from the physiological effects of prolonged stress.
Thank you. The article says “changes to their DNA”, which is not epigenetics, strictly speaking. The change described does seem to be within that realm, though, being a change in the celluar environment related to DNA expression. It’s still hard to believe that high level interpretations of sensory experience, such as “abuse”, could lead to such deep chemical alterations at the celluar level.
Paging Dr. Paul Kammerer.
Maybe. That wouldn’t mean that the changes induced by abuse aren’t real, and harmful.
I was doomed from the start.
If you’d lived for 37 years with the “side effects” of abuse, I bet you wouldn’t say that.
For some of us, this explains why *nothing* we do ever “erases” the damage.
This seems to imply we were “wet-wired” into what we are, now.
And not to put too fine a point on it, it *seriously* sucks and “changes” your whole life, right down to the tiniest details.
[and for all I know, it changes it forever which I can’t provide proof for since I’m still alive and “forever” hasn’t come yet]
“However, I’ve always wondered whether the nervous system has some kind of mechanism to protect the organism from the physiological effects of prolonged stress.”
Generalized anxiety disorder, panic attacks, depersonalization, derealization, withdrawal, anti-socialism, multiple personality disorder are all “mechanisms” to “shield” the person from the initial event.
They’re all types of psychological “displacement behavior”.
When your brain can’t cope with the real trauma, it will often manufacture other more generalized and vague anxieties to keep you from focusing on the real injury.
It’s also a pop-science article in which scientific precision runs about 80% in most cases. Methylation of DNA is a pretty well established fact.
Those sound to me like symptoms of the action of whatever mechanism is present. Kind of like saying that rhinitis or asthma are mechanisms to fight allergens.
Just run of the mill mental “coping mechanisms”.
I mean, you got your "psychopathology of everyday life" over here, and then you have more pronounced clusters of behavior. Among these, in no particular order,would be inability to stay focused in a conversation, depressed behavior, evasion in counseling, failure to complete tasks agreed to, sleeplessness, abuse of alcohol, remarkable neatness, blah blah.
Sometimes, as in alcohol abuse, the thing to do is to address the "symptom" directly. Aside from anything else, doing so can improve the quality of life and get the client "Well" enough to pursue other matters.
Other times, and I'm thinking here of evasiveness in counseling, the behavior is just data to be pondered as indicative of and a response to something else.
Even then, I guess a frequently encountered course is,
What makes it fun is when the coping mechanism works okay for the person with the, sort of, primary problem but makes life miserable for others.
I once said to the chief deputy, only half-joking, "You don't suffer from stress; you're a carrier." Of course what was going on was that his position gave him space to "act out" (in the strict sense, not in the modern sense of "misbehave") so that others experienced the stress he was not able to confront in himself.
Blah blah. I need more coffee and to quit displacing my anxiety about the day ahead...
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