People with low risk for cocaine dependence have differently shaped brain to those with addiction

People who take cocaine over many years without becoming addicted have a brain structure which is significantly different from those individuals who developed cocaine-dependence, researchers have discovered. New research from the University of Cambridge has found that recreational drug users who have not developed a dependence have an abnormally large frontal lobe, the section of the brain implicated in self-control. Their research was published in the journal Biological Psychiatry.

For the study, led by Dr Karen Ersche, individuals who use cocaine on a regular basis underwent a brain scan and completed a series of personality tests. The majority of the cocaine users were addicted to the drug but some were not (despite having used it for several years).

The scientists discovered that a region in the frontal lobes of the brain, known to be critically implicated in decision-making and self-control, was abnormally bigger in the recreational cocaine users. The Cambridge researchers suggest that this abnormal increase in grey matter volume, which they believe predates drug use, might reflect resilience to the effects of cocaine, and even possibly helps these recreational cocaine users to exert self-control and to make advantageous decisions which minimize the risk of them becoming addicted.

They found that this same region in the frontal lobes of the brain was significantly reduced in size in people with cocaine dependence, confirming earlier research that had found similar results. They believe that at least some of these changes are the result of drug use, which causes drug users to lose grey matter.

They also found that people who use illicit drugs like cocaine exhibit high levels of sensation-seeking personality traits, but only those developing dependence show personality traits of impulsivity and compulsivity.

Dr Ersche, of the Behavioural and Clinical Neuroscience Institute (BCNI) at the University of Cambridge, said: “These findings are important because they show that the use of cocaine does not inevitably lead to addiction in people with good self-control and no familial risk.

What Is Cocaine? How Addictive Is Cocaine?
Cocaine is a bitter, addictive pain blocker that is extracted from the leaves of Erythroxylon coca, also known as the coca scrub, a plant that comes from the Andean highlands in South America. Cocaine is the most powerful stimulant of natural origin. The name of “cocaine” came from the plant “coca”. When Coca-Cola first came out it contained nine milligrams of cocaine per glass - in 1903 it was removed, but the drink still has coca flavoring.

William S. Halstead (1852-1922), an American surgeon, injected cocaine into nerve trunks and demonstrated its numbing effect. It soon became used as an anesthetic agent. In 1898 August Bier, a German surgeon used cocaine as a spinal anesthetic. Not long afterwards the medical profession became aware of the addictive nature of cocaine and safer anesthetics were developed. Cocaine in its basic form stopped being used clinically as a pain blocker.

Today, cocaine is commonly used as a recreational drug.

“Our findings indicate that preventative strategies might be more effective if they were tailored more closely to those individuals at risk according to their personality profile and brain structure.”

The researchers will next explore the basis of the recreational users’ apparent resilience to drug dependence.

High risk of addiction
Animal laboratory studies have demonstrated how addictive cocaine can be. Animals will work much more persistently for a cocaine bar than any other drug, even opiates. Addicted humans eventually prefer taking cocaine to any other activity - their lifestyles may alter completely as the addiction takes hold more firmly. There have been cases of mothers selling their child, professionals spending thousands of dollars with binges costing from $20,000 to $50,000. Some may lose their jobs, families, become bankrupt, and even die.

Brain alterations - scientists at the University of Cambridge, England, identified abnormal brain structure in the frontal lobe of the brain of cocaine users that are associated with their cocaine-using behavior. They scanned the brains of 120 individuals, half of whom were addicted to cocaine. They found that the cocaine users had widespread loss of grey matter that was directly linked to how long they had been using cocaine - the longer the abuse, the greater the loss. They also found that those with the most reduction in volume had the greatest cocaine compulsivity.

They also found that the basal ganglia, the brain reward system where cocaine exerts its actions, was much larger among those dependent on cocaine. However, there was no association between the size of the enlargement and how long the person had been doing cocaine. The scientists believe that the enlargement may have occurred before cocaine usage, meaning that there are people who are more vulnerable to the effects of cocaine.

Dr Ersche added: “Their high level of education, less troubled family background or the beginning of drug-taking only after puberty may all play a role.”


Effects/Side Effects

The cocaine high can change how a person feels emotionally, as well as changing the way they think. According to the CESAR website, the initial cocaine high lasts around 15-minutes. Cocaine affects the nervous system, as well as the brain, which means each cocaine user is likely to experience a unique high. Feelings of intense pleasure and complete euphoria are the most common high described by users of cocaine. This is one reason why people become addicted so quickly. An increase in self-confidence and social awareness is also common, with people instantly becoming more gregarious and talkative. The effect of coming down from cocaine will start as soon as the effects of the drug begin to dissipate. This comedown is often long and can leave a person feeling drained, tired and depressed. Also known as a cocaine crash, this comedown can continue for days afterwards. This is another reason people are quick to take more cocaine. Although the side effects of cocaine may be frightening, a person may be too frightened to seek advice or help. If you require information on our inpatient or outpatient services, you can call 1-877-653-9087 or alternatively, you can complete the quick reply form.

For additional information please contact:

Genevieve Maul
Office of Communications
University of Cambridge
Tel: 44-1223-332-300
Mob: 44-7774-017-464
Email: .(JavaScript must be enabled to view this email address)

Notes to editors:
1. The paper ‘Distinctive Personality Traits and Neural Correlates Associated with Stimulant Drug Use Versus Familial Risk of Stimulant Dependence’ was published in Biological Psychiatry.

2. This work was funded by a Medical Research Council (G0701497) and received institutional funds from the Behavioural and Clinical Neuroscience Institute (BCNI), which is jointly funded by the Medical Research Council and the Wellcome Trust.


Genevieve Maul
.(JavaScript must be enabled to view this email address)
University of Cambridge

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