Drug Addiction: Environmental Conditions Play Major Role In Effective Treatment And Preventing Relapses, Animal Study Shows

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.

Note:

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.