Addiction, compulsive and pathological drug consumption, also exists in the rat

Addiction, defined as compulsive and pathological consumption of drugs, as are rats, show for the first time, French researchers, opening up new prospects for understanding the phenomenon of addiction

This is not only a characteristic of the human species

So far, the scope of animal models used to study the drug was limited because if the animals were able to show a voluntary drug, true addiction, characterized by compulsive aspect of drug research, was not found in these animals. So scientists thought that addiction as pathological as use of drugs, was a characteristic of the human species.

The work of the team Pier-Vincenzo Piazza (Inserm 588 "Pathophysiology of behavior" Unit) are against this idea and suggest that all behaviors defining addiction in humans also exist in the rat who self-administer cocaine.

The researchers followed for three months (very long time in the life of this rodent does not live more than three years) 100 rats, whose movements were free. Animals could self-administer cocaine when they dug their noses into a hole in their experimental chamber.

During this period, three behavior characteristics of drug addiction in humans, were studied daily: it hard to stop taking drugs, high motivation to research the drug and continued use despite adverse consequences .

After two or three months, all rats were cocaine users and 17% had three criteria for addiction. For comparison, the rate of people developing a behavior addiction is estimated at 15% in human cocaine users.

Dependent rats also showed a higher propensity to relapse (after 5-30 days of abstinence) that consumers rats did not develop criteria for addiction.

"As with humans, the behavior characteristic of addiction is present in only a small proportion of consumer topics cocaine and is highly predictive of relapse after stopping the drug," the authors conclude.

"The description of the animal opens perspectives model for understanding the biological basis of addiction and find treatment," he coommenté to Reuters Health Pier-Vincenzo Piazza.

Addiction as a brain disease

From these results, the authors believe that the development of addiction is not solely the result of prolonged exposure to the drug, but also due to the vulnerability of individuals to addiction, because despite taking same product, only a small fraction will be dependent.

"Until now, there were two theories to explain addiction. The prevailing theory was based on the exposure to the product and described the disorder as an iatrogenic disease, while another approach was to identify the vulnerability of users, making addiction a disease of behavior, "said Pier-Vincenzo Doge.

His study proposes a unified vision describing the drug not only a social problem but as a disease of behavior.

"The drug seems therefore have identical to other brain diseases status that most often result of an interaction between a pathogen and an environmental stimulus field predisposition," he says.