Siblings' brain may hold key to drug addiction: Research

Researchers at the University of Cambridge have identified a brain abnormality which is found in drug-dependent individuals as well as their siblings who have had no history of drug addiction.

The brain abnormality identified by the researchers makes it more difficult for individuals to exercise self-control. This research will help understanding about why some people with a family history of drug abuse are at a higher risk of addiction than others. The findings are published on Friday in the journal Science, a university release said.

Led by Dr Karen Ersche, the researchers scanned the brains of 50 pairs of brothers and sisters, of whom one was dependent on cocaine while the other did not abuse drugs or alcohol.

Their brains were compared with those of 50 unrelated healthy volunteers who had no personal or family history of drug addiction. The researchers found that both the drug-dependent and their non-dependent siblings shared the same abnormality in the parts of the brain associated with how we control our behaviour, known as the fronto-striatal systems.

This kind of abnormality is typically seen in people who struggle with drug addiction.
Dr Karen Ersche, of the Behavioural and Clinical Neuroscience Institute at the University of Cambridge, said: “It has long been known that not everyone who takes drugs becomes addicted, and that people at risk of drug dependence typically have deficits in self-control.

“Our findings now shed light on why the risk of becoming addicted to drugs is increased in people with a family history of drug or alcohol dependence: parts of their brains underlying self-control abilities work less efficiently.” The use of addictive drugs such as cocaine further exacerbates this problem, paving the way for addiction to develop from occasional use, he said.

Dr Ersche added: “Given that some forms of drug addiction are thought to develop out of bad habits that get out of control, it’s intriguing that siblings who don’t abuse drugs show similar brain abnormalities as the ones who have been abusing drugs for many years.