Brain abnormalities linked to cocaine addiction

By William Smith

New research carried out by Cambridge scientists has revealed that cocaine users had a ‘dramatic decrease in grey matter’ in their frontal lobes.

This could affect several key brain functions including decision-making, memory and attention as some of their brain’s rewards systems were significantly larger.

The scientists have found ‘significant abnormalities’ in the brains of those addicted to cocaine. This could help explain the compulsive nature associated with the use of the drug. It is felt that this could also point to why some people are more likely to become addicts.

The Behavioural and Clinical Neuroscience Institute at the University of Cambridge, led by Karen Ersche, found that the longer a person had been using cocaine, the poorer their attention was and the more compulsively they used the drug.

Ms Ersche said ‘That is the hallmark of cocaine dependence – namely, that most of them are intelligent people who go to great extents to buy cocaine, to get more cocaine, to put their jobs at risk, their families at risk. They feel like they’re driven to use more.’

The journal ‘Brain’ published the results of this study last week. It explains that Ersche and her team scanned the brains of 60 people who were dependent on cocaine and compared them to the scans of 60 people without any history of drug-taking.

‘We found significant abnormalities in the brains of the cocaine users’ Ersche said.

An area which involves decision-making and goal-directed behaviour, namely the orbitofrontal cortex, was reduced in people with cocaine addiction.

The insula was also affected, this is an area of the brain involved in feedback processing, learning and feelings of cravings. The grey matter in the anterior cingulated was also reduced – this part of the brain is involved in emotional processing and being attentive.

The chordate nucleus, a region deep in the brain associated with reward processing, attention and motor movements, as enlarged in those addicted to cocaine. This could explain why they were more prone to addiction but the scientists cannot be sure whether the enlargement is a result of the use of cocaine.

Although links were found between brain structure and cocaine use Ersche said that her research was not yet conclusive as to which came first.

‘At the moment, correlation shows me a direct relationship, but I don’t know which direction the relationship is. Has this been caused by cocaine, or are people who have this abnormality more vulnerable?’

She concluded ‘We basically show that cocaine is a disorder of the brain, which is a big step. For a lot of people it is still a moral issue and willpower has nothing to do with the brain.’

If we know that some areas of the brain are abnormal, Ersche said, then this means that scientists can try to work out ways to train or medicate the brain to get around the damage.

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