Summary

Drugs change the biochemical makeup of the brain for a long time, and the changes persist long after one stops taking drugs. This presumably explains why drug addiction appears to be a chronic and relapsing disease. Laboratory research has shown that this finding can be understood in terms of drugs causing changes in levels of functionally important proteins. The mechanisms that drugs might use can include epigenetic changes or other changes in gene regulation. However this limited understanding needs substantial improvement. The realization that the brain changes for a long time has had a major impact on our goals and methods for developing and delivering treatments. Because the duration of the changes might be different for different dru....