Led by Doctor Karen Ersche, Behavioural and Clinical Neuroscience Institute (BCNI), the Cambridge researchers scanned the brains of 120 people, half of whom had a dependence on cocaine. They found that the cocaine users had widespread loss of grey matter that was directly related to the duration of their cocaine abuse (for example the longer they had been using cocaine, the greater the loss of grey matter), and that this reduction in volume was associated with greater compulsivity to take cocaine.

The scientists also found that parts of the brain reward system where cocaine exerts its actions (the basal ganglia) were significantly enlarged in cocaine users; but the size of the enlargement was not related to the duration of cocaine use. The researchers believe this may suggest that alterations in the brain's reward system predate cocaine abuse, possibly rendering these individuals more vulnerable to the effects of the drug.

Ersche said: "This research gives us important insight into why some people are more vulnerable to drug addiction. Not only is this important for the future development of more effective therapeutic interventions for people who have become dependent on drugs, it will also inform improved strategies to prevent drug addiction in the first place."

Cocaine, one of the most addictive drugs on the illicit drug market, exerts its effects on the brain by changing the way a person thinks and feels. People addicted to cocaine feel an overwhelming, uncontrollable need for the drug, even in the face of aversive consequences.

Ersche added: "People with cocaine dependence describe their out-of-control drug use as a 'compulsion' to use cocaine. Our current work has laid the foundation for a better understanding of cocaine dependence and why this compulsion occurs."

MEDICA.de; Source: University of Cambridge