What do alcohol and illicit drugs do to the brain

Whether its alcohol, nicotine, prescription painkillers, heroin, or cocaine addictive substances change the brain in fundamental ways. All of these substances act on "reward pathways" in brain, releasing a rush of neurochemicals to produce a euphoric high. With continued use, underlying brain circuits physically change. In people at risk, this drives a destructive cycle of compulsive drug craving and usage aimed at recreating high. (Some people are more susceptible to this cycle than others, for complex reasons.) An addict may become so focused on "drug-seeking" that everything else in life is secondary. Without treatment, quitting is difficult or impossible.