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Brain Changes Cause Drug Addiction, Researchers Say
Drug addicts andِ their nonaddict siblings share theِ sameِ brain abnormalities linked withِ poor self-control andِ drug dependence, a newِ study suggests.
Researchers looked atِ pairs ofِ siblings andِ healthy, unrelated people, andِ compared theirِ brain structures andِ their ability toِ control theirِ impulses — whichِ isِ known toِ beِ compromised among drug abusers.
Researchers haveِ known thatِ the brains ofِ people addicted toِ drugs differ fromِ those ofِ others, butِ it hasِ not beenِ clear whetherِ thisِ isِ a causeِ or effect ofِ addiction.
The study is published today (Feb. 2) in the journal Science.
Drug addiction, a disease of the brain
Every year, theِ abuse ofِ illegal drugs andِ alcohol contributes toِ theِ death ofِ moreِ than 100,000 people inِ the U.S., according toِ theِ National Institute onِ Drug Abuse.
Drug addiction isِ the disease ofِ the brain, Ersche said.
It falls inِ the sameِ category asِ other psychiatric disorders thatِ areِ serious andِ have a basis inِ the brain.
Previous studies have shown that genes play a role in predisposing people to drug abuse.
We knowِ through twin studies, ifِ one twin suffers fromِ addiction, theِ identical twin hasِ a 50:50 chance ofِ alsoِ having anِ addiction, saidِ Dr.
Andrew Saxon, anِ addiction psychiatrist atِ the University ofِ Washington, whoِ wasِ notِ involved withِ theِ newِ study.
But Saxon saidِ people’s life experiences andِ environment affect theirِ choices, asِ well asِ their brain structures andِ genes.
Same brain abnormalities, different life experiences
Ersche andِ colleagues studied 50 pairs ofِ siblings — oneِ who hadِ a history ofِ drug addiction, andِ one whoِ didn’tِ — andِ compared themِ with 50 healthy people.
Researchers tested allِ participants’ ability toِ control theirِ impulses usingِ a stop-signal reaction time’ test, whichِ measures howِ quickly a person canِ switch fromِ followingِ one set ofِ instructions toِ another.
They found that the siblings performed poorly on the test, compared with the other people.
Moreover, brain images revealed abnormalities shared byِ the siblings thatِ weren’t foundِ in theِ healthy people.
These abnormalities included a decrease inِ the density ofِ white matter inِ the front ofِ the brain, whichِ suggests a decrease inِ self-control, andِ anِ increase inِ gray matter inِ the middle regions ofِ the brain, whichِ suggests anِ increased ability toِ form habits, according toِ theِ study.
Saxon saidِ the study providesِ strong evidence thatِ the brains ofِ drug abusers wereِ differentِ beforeِ they started takingِ drugs.