Brain scans reveal biological basis of cocaine addiction

Researchers looking at brain activity of cocaine users may have identified a biological lack of willpower’ that will help us understand why some people become long-term addicts while others can use the drug socially.

Researchers will present their findings at a scientific meeting at the Royal Society.

By taking brain scans of cocaine users while they performed computer tasks that assessed both impulsive behaviour and the brain’s response to making a mistake’, scientists at Trinity College Dublin have been able to identify the exact regions of the brain affected by cocaine. The scans show that cocaine alters the parts of the brain responsible for controlling behaviour and making appropriate decisions.

Dr Hugh Garavan said: “Non-invasive brain imaging allows us to study the biology behind willpower’ which, until now, most people would think of as something that cannot be measured objectively’ using scientific investigation. This research helps us move away from thinking of drug dependence as a moral weakness and allows us to see it as more of a medical condition.

“Research into drug abuse has tended to focus on the emotional aspects of addiction such as pleasure seeking, craving and withdrawal. But, by using brain scans to study impulse control’ the brain’s ability to control a person’s actions we can see the direct effects that cocaine has on the brain’s ability to control behaviour.

“Cocaine’s effect on this impulse control’ may account for why some users find it easier to quit than others. In the future this may lead to an understanding of why some people develop long term addictions to cocaine and others don’t.

“Understanding the role that our brain plays in addiction may also have important implications for treating long term addiction and designing intervention therapies. Importantly, new medication based on certain chemical processes in the brain could be developed as currently there are no good pharmacological treatments for cocaine. Traditional treatment therapy such as counselling or rehab could also be adapted to train addicts to monitor their behaviour and practice impulse control.”

Dr Garavan’s research also found that there are differences in the brain structures of cocaine users. This has significant consequences for how society perceives and treats addicted users.

Dr Garavan said: “It is still unclear whether the differences we see in cocaine users’ brains existed before they began taking cocaine or whether they are a result of use, or both. It is more a case of trying to understand as much as possible about the underlying brain function of addicts. One would hope this research would guide the development of new treatments including the development of pharmacological solutions to addiction.”

Dr Garavan will be presenting his research at a Royal Society discussion meeting which takes place on Monday 25 February and Tuesday 26 February 2008.

A collection of papers from the speakers at the discussion meeting on The neurobiology of addiction: New vistas’ will be published in a special edition of Philosophical Transactions of the Royal Society B: Biological Sciences which is due to be published online in September 2008.

Source: The Royal Society, UK

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