Addiction is due to changes in the structure and function of the brain, including neuronal
networks and the cells that comprise them. Within cells, gene expression changes can track
and help explain their altered function. Transcriptional changes induced by addictive agents
are dynamic and divergent and range from signal pathway-specific perturbations to
widespread molecular and cellular dysregulation that can be measured by “omic” methods
and that can be used to identify new pathways. The molecular effects of addiction depend on …