Researchers at the Medical Research Council-funded Behavioural and Clinical Neuroscience Institute (BCNI), University of Cambridge, have identified abnormal structures in the brains of cocaine users which are linked to their compulsive drug-using behaviour.
The researchers, led by Dr Karen Ersche from the BCNI, scanned the brains of 120 people, half of whom had a dependence on cocaine. They 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 suggest that alterations in the brain's reward system pre-date cocaine abuse, possibly rendering these individuals more vulnerable to the effects of the drug.
The scientists also found that the cocaine users had a widespread loss of grey matter and that the longer they had been taking the drug, the greater the loss of this brain material. This reduction in volume was then linked with having a greater compulsion to take cocaine, worsening the problem.
With a grant from the Medical Research Council, Dr Ersche is now exploring whether there is an inherited vulnerability to develop cocaine dependence. Her team will research whether people with an enlarged brain reward system are more at risk of becoming dependent on cocaine, as well as the effects of recreational cocaine on the brain.
Dr Ersche said:
"This research gives us an 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, it will also inform improved strategies to prevent drug addiction in the first place. These findings show that cocaine dependence is a disorder of the brain, which is very relevant information for the treatment of people who are trying to beat their addiction”
Professor Chris Kennard, chairman of the MRC funding board which funds Dr Ersche, said:
“Addiction and substance misuse is a major medical, social and economic problem for the UK, and the MRC places great emphasis on research into addiction and developing ways to tackle this in the population. Dr Ersche’s research, alongside other studies within the Medical Research Council/Wellcome Trust Behavioural and Clinical Neuroscience Institute, is providing important new insights into the brain mechanisms underlying addictive behaviour, and represents another exciting step in delivering the MRC’s research agenda in this area.”
This study was funded by GlaxoSmithKline and conducted within the GlaxoSmithKline Clinical Unit Cambridge and BCNI (which is co-funded by the MRC and the Wellcome Trust).
The paper, 'Abnormal structure of frontostriatal brain systems is associated with aspects of impulsivity and compulsivity in cocaine dependence' by K.D. Ersche, A. Barnes, P.S. Jones, S. Morein-Zamir, T.W. Robbins, and E.T. Bullmore et al. is published in the June edition of Brain.
22 June 2011
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