Drug Addiction: Environmental Conditions Play Major Role In Effective Treatment And Preventing Relapses
Environmental conditions play a major role in treating drug addiction and in preventing relapses, according to new research. For the first time, researchers from the Institut de physiologie et biologie cellulaire (CNRS/Université de Poitiers) have shown that positive and stimulating environmental conditions make it easier to treat cocaine addiction.
Even though numerous data exist on the mechanisms of cocaine addiction, there are as yet no effective therapies, making it very urgent that new strategies for treating the disease be developed. According to a study by Marcello Solinas and Mohamed Jaber, carried out by a group of researchers at the Institut de physiologie et biologie cellulaire in Poitiers, exposing mice to an “enriched environment (1)” during cocaine withdrawal removes abnormal behavior related to addiction. An enriched environment, for mice, is an environment which stimulates their curiosity, providing social and physical activity as well as exploration.
After addicting animals to cocaine, the researchers then exposed them to an enriched environment made up of large cages with a small house, a running wheel, tunnels and other appealing toys which were changed weekly.
Three models of animal addiction were used:
* behavioral sensitization, which measures the progressive increase in the stimulating effects of cocaine after chronic administration;
* the location preference, which measures the ability of a context (associated with cocaine consumption) to lead to drug-seeking behavior, and the renewal of this drug-induced location preference;
* measurements of cocaine’s ability to lead to a relapse after a period of withdrawal.
The result was that after thirty days of exposure to an enriched environment, addiction behavior typical of these three models had disappeared.
To identify the brain areas involved in the beneficial effect of an enriched environment, the researchers used an approach from functional neuro-anatomy. They showed that the absence of relapse in “enriched” mice was associated with a decrease in the cocaine-induced activation of a set of brain structures involved in dopaminergic transmission and associated with relapse.
These results, which have both a medical and societal impact, suggest that the living conditions of drug addicts should be taken into account in determining their therapy. A real effort should be made to create enriched environmental conditions, providing patients with different types of social, physical and intellectual stimulation. This also suggests that under deprived environmental conditions, treating addiction can be very challenging.
1) A number of earlier studies had shown that when animals are raised in an enriched environment prior to drug exposure, their vulnerability to addiction was reduced. In such conditions, the enriched environment can be seen as preventive.
Proceedings of the National Academy of Sciences, 2008; 105 (44): 17145
Reversal of cocaine addiction by environmental enrichment
Marcello Solinas, Claudia Chauvet, Nathalie Thiriet, Rana El Rawas, and Mohamed Jaber
Edited by James L. McGaugh, University of California, Irvine, CA, and approved September 17, 2008 (received for review July 17, 2008)
Environmental conditions can dramatically influence the behavioral and neurochemical effects of drugs of abuse. For example, stress increases the reinforcing effects of drugs and plays an important role in determining the vulnerability to develop drug addiction. On the other hand, positive conditions, such as environmental enrichment, can reduce the reinforcing effects of psychostimulants and may provide protection against the development of drug addiction. However, whether environmental enrichment can be used to “treat” drug addiction has not been investigated. In this study, we first exposed mice to drugs and induced addiction-related behaviors and only afterward exposed them to enriched environments. We found that 30 days of environmental enrichment completely eliminates behavioral sensitization and conditioned place preference to cocaine. In addition, housing mice in enriched environments after the development of conditioned place preference prevents cocaine-induced reinstatement of conditioned place preference and reduces activation of the brain circuitry involved in cocaine-induced reinstatement. Altogether, these results demonstrate that environmental enrichment can eliminate already established addiction-related behaviors in mice and suggest that environmental stimulation may be a fundamental factor in facilitating abstinence and preventing relapse to cocaine addiction.