The Met158 gene variation has been found to cause an exaggerated “startle” response among people prone to develop Anxiety Disorders.
Inborn differences may help explain why trauma gives some people bad memories and others the nightmare of Post Traumatic Stress Disorder. Scientists in Germany and the United States report evidence in a new study linking genes to Anxious behavior. The findings appear in the August issue of Behavioral Neuroscience, published by the American Psychological Association.
Although a great deal more research is needed, Christian Montag, co-author of the research, says that if this line of research bears fruit, one day
it might be possible to prescribe the right dose of the right drug, relative to genetic makeup, to treat anxiety disorders.
The specific genes involved in the study
The Met158 gene works with dopamine
The COMT gene encodes an enzyme that breaks down dopamine, an important brain chemical, which weakens its signal. The two variations of the COMT gene are Val158 and Met158.
About half of the population carries one copy of each variation. Twenty-five percent carries two copies of the Val158 variation, and the remaining 25% carries two copies of the Met158 variation.
How the research was carried out
Eliciting the startle response
The researchers first determined which of the 96 participants carried which variations of the COMT gene. They also administered a standard personality test to determine if the participants had any Anxious traits. Then they used a well-known test which uses pictures and loud noises to elicit the startle response.
The results of the research
The research confirms that specific variations in the gene that regulates dopamine may play a role in negative emotions. The authors speculate that the Met158 variation may raise levels of dopamine in the brain’s limbic system, a set of structures that support memory, emotional arousal and attention.
Met158 gene: focus even if bad
The researchers said that more dopamine in the prefrontal cortex could result in an “inflexible attentional focus” on unpleasant stimuli. And the “inflexible attentional focus” on unpleasant stimuli means that Met158 carriers can’t tear themselves away from something that’s arousing — even if it’s bad.
Met158 gene: strong startle, greater anxiety
People carrying two copies of the Met158 variation of the COMT gene showed a much stronger startle reflex than did the other participants. Significantly, they also showed greater anxiety on a standard personality test.
More research is needed
More prone to Anxiety Disorders
The researchers offer a biochemical explanation for why some people find it harder to regulate emotional arousal. These people’s sensitivity may, in combination with other hereditary and environmental factors, make them more prone to Anxiety Disorders.
Montag says that a single gene variation can explain only a small portion of variation in Anxious behavior. Otherwise, in theory, up to half the population could be anxious! He cautions,
This single gene variation is potentially only one of many factors influencing such a complex trait as anxiety. Still, to identify the first candidates for genes associated with an anxiety-prone personality is a step in the right direction.
What do you think?
There is physical evidence for mental illness
There are many who deny there is any physical evidence for mental illness. This study is just one among many that shows that there is physical evidence, and new studies are coming out every few days adding to that evidence.
That does not mean we are slaves to our genes, or to the chemicals in our brains, but that we who are prone to Anxiety Disorders must be extra careful — just like those prone to diabetes must be extra careful. There is a huge complex of reasons for getting Anxiety Disorders, some known and some yet to be discovered.
But one of the most important things we do know is the role of stress in Anxiety Disorders, both in those prone to it, and those who already have it. Changing your lifestyle to eliminate stress is one of the best things you can do to combat Anxiety Disorders!
- How important do you think the findings of this research are?
- What role do you think that stress plays in Anxiety Disorders?
As always, your comments are welcome!
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Resources used in this post:
American Psychological Association. (2008, August 10). Genes May Make Some People More Prone to Anxiety. Retrieved August 29, 2008 from American Psychological Association Web site: http://www.apa.org/releases/genes0808.html
Medical News Today. (2008, August 11). Genes May Make Some People More Prone To Anxiety. Retrieved August 29, 2008 from Medical News Today Web site: http://www.medicalnewstoday.com/articles/117820.php
Montag, Christian; Buckholtz, Joshua W.; Hartmann, Peter; Merz, Michael; Burk, Christian; Hennig, Juergen. (2008). COMT Genetic Variation Affects Fear Processing: Psychophysiological Evidence. Retrieved August 29, 2008 from American Psychological Association Web site (PDF): http://www.apa.org/journals/releases/bne1224901.pdf
Science Daily. (2008, August 11). Genes May Make Some People More Prone To Anxiety. Retrieved August 29, 2008 from Science Daily Web site: http://www.sciencedaily.com/releases/2008/08/080810214000.htm