Brain switch clues to drug addiction

When considering the biological route of drug addiction, research at Cambridge University is revealing what makes some people more vulnerable than others with regard to addictions. It is believed that there is a cause that connects the switch from occasional, 'recreational' use to a serious compulsive habit. Professor Everitt and his team of researchers in the Cambridge lab have discovered that there is a shift in the control of drug seeking behaviour in the brain. For example, cocaine generates reinforcing or 'rewarding' effects mediated by certain areas of the brain, while for other people drug taking escalates to become a strong habit with difficulties to give it up and therefore there is "habit learning".

Some individuals are vulnerable to this switch from one brain region to another as was expressed by Professor Everitt from Cambridge University. It is also expressed in this article that people who are addicted to drugs tend to be impulsive, a characteristic which may have a genetic, as well as an environmental basis.

Compulsive drug seeking is a key diagnostic feature of addiction and this only emerges after a prolonged drug taking history. Professor Everitt's lab has also shown that individuals who were initially impulsive are also eventually vulnerable to take cocaine compulsively. This tendency may be exacerbated by a loss of 'executive' - or higher - control over the drug seeking habit through toxic effects of chronically self-administered drugs on the prefrontal cortex of the brain. Drug seeking can therefore be seen as a complex series of interactions between vulnerability traits and learning mechanisms.

"Impulsivity clearly interacts with chronic drug taking to precipitate the compulsive drug seeking state of addiction. We are beginning to unravel the neural basis of this interaction," said Professor Everitt. The results suggest that future treatments may be those that reduce impulsivity, since they may help to prevent relapse in people who are striving to overcome addiction. Association to dopamine and dopaminargic receptors are also explored as well as environmental influences.

You can read more here.

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