- New findings suggest that experiences can contribute to mental illness by adding or removing “epigenetic” marks on chromosomes. These tags are particular chemicals that can influence gene activity without changing the information encoded in the genes.
- Studies in mice demonstrate a role for long-lasting epigenetic modifications in such disorders as addiction and depression.
- Epigenetic changes can also affect maternal behaviors in ways that reproduce the same behaviors in their offspring, even though the changes are not passed down through the germ line.
- Researchers hope the new findings will lead to better treatments, although the path to those treatments is not yet obvious.
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Matt is a history teacher. his twin brother, greg, is a drug addict. (Their names have been changed to protect their anonymity.) Growing up in the Boston area, both boys did well in high school: they were strong students in the classroom and decent athletes on the field, and they got along with their peers. Like many young people, the brothers snuck the occasional beer or cigarette and experimented with marijuana. Then, in college, they tried cocaine. For Greg, the experience derailed his life.
At first, he was able to function normally—attending classes and maintaining connections with friends. But soon the drug became all-important. Greg dropped out of school and took on a series of menial jobs in retail and fast-food joints. He rarely held a position for more than a month or two, generally getting fired for missing too much work or for arguing with customers and co-workers. His behavior became increasingly erratic—sometimes violent—and he was arrested repeatedly for stealing to support his habit. Multiple efforts at treatment failed, and by the time the courts sent Greg, then 33 years old, to a psychiatric hospital for evaluation, he was destitute and homeless: disowned by his family and a prisoner of his addiction.