Pubdate: Mon, 05 Feb 2007
Source: Independent (Malta)
Copyright: 2007, Standard Publications Ltd
Author: Juan Ameen
Bookmark: (Cocaine)


Although a vaccine for cocaine addiction has been discovered, as with 
every scientific discovery it is now up to society to choose whether 
to make use of it or not, said Professor Richard Muscat.

Prof. Muscat, Professor of Behavioural Neuroscience at the University 
of Malta was commissioned by the Pompidou Group to write a paper 
discussing the implications of the TA-CD vaccine.

The Pompidou Group is an inter-government body formed in 1971 that 
studies and compares drug use trends in Europe and was instrumental 
in setting up the European School Survey Project on Alcohol and other 
Drugs (ESPAD Report).

The concept behind the TA-CD vaccine is very simple: cocaine blocks 
nerve cells from absorbing dopamine, a chemical substance produced by 
the brain that controls pain relief. The blockage creates an 
overabundance of dopamine in between nerve cells, leading to what is 
known as "a cocaine high."

The TA-CD vaccine makes ingested cocaine attach itself to a larger 
protein molecule, while at the same time causing the immune system to 
recognise and combat this larger protein molecule before the attached 
cocaine is able to reach the brain. The TA-CD vaccine does not 
actually stop someone from wanting to consume cocaine, but it does 
inhibit the "high".

Studies conducted in the US and in England show promising results: 
the vaccine was developed in the UK and was tested on 18 cocaine 
addicts over a period of 14 weeks.

According to the results, three quarters of the vaccinated group of 
addicts were drug free for a period of three months.

Furthermore, after six months, both those who had relapsed and those 
who had not, said that the "high" was not as strong as before taking 
the vaccine.

In the US, where studies were funded in part by the US National 
Institute on Drug Abuse and which used the largest number of 
subjects, patients were able to remain off cocaine for six months.

Additionally, parallel but separate studies indicate that an 
individual's pre-existing brain chemistry can increase his or her 
predisposition to become addicted to cocaine, opening the door to 
prevention strategies that test for this predisposition.

At present there are no medical treatments available for cocaine 
addiction, Prof. Muscat said.

The reason appears to be the mechanism of action through which 
cocaine exerts its effects on the brain neurotransmitters dopamine 
and serotonin.

Heroin binds to brain opioid receptors, such as the mu receptors, and 
therefore mimics the action of the brain's own endorphins.

However, cocaine inhibits the reabsorption of dopamine and seratonin, 
leading to a build-up of the transmitter, thus prolonging and 
strengthening its effect, he explained.

Prof. Muscat said it does not mean that it is not possible to develop 
a medical treatment for cocaine addiction - only that it may be more 
difficult to do so and may involve different concepts.

Every single organism has a pleasure pathway wired in his or her 
brain, he explained. "All a drug does is amplify the feel-good factor."

Furthermore, the TA-CD vaccine does not switch off the craving for 
the drug. "What researchers are suggesting is that it is administered 
only after the person has undergone rehabilitation."

Prof. Muscat explained that research has found that 50 per cent of 
dependent substance abusers may be genetically related.

"Therefore this raises a number of ethical issues such as: do we 
administer the vaccine to 10-year-olds who have a predisposition for 
substance dependency?" queried Prof. Muscat.

However, even though the vaccine has yet to be approved for the 
general population, researchers from around the world are already 
raising objections to widespread use of the vaccine on ethical grounds.

In his paper Biomedical research in the drugs field, Prof. Muscat 
discusses the ethical issues behind the vaccine.

Should it be used, asked Prof. Muscat, "for example where adolescents 
are considered to be at risk of developing cocaine dependency? Do we 
vaccinate all young people with increased vulnerability?"

Prof. Muscat pointed out that as not every individual's brain 
chemistry reacts to cocaine in the same way, administering a vaccine 
indiscriminately would be cause for concern.

However, he added, administering the vaccine to people identified as 
having a predisposition to cocaine addiction, might end up stigmatising them.
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