Washington Post: How heroin changes the brain of an addict

This is a good and highly readable discussion of neurological changes that occur with repeated use of psychoactive substances and  perpetuate addiction.  It highlights changes to the reward regions of the brain, explaining that the brain responds to drug-induced floods of dopamine by dampening its response to this neurotransmitter, and possibly to “all forms of pleasurable behavior”. Hence, addicts “seek larger and larger hits to achieve an ever-diminishing pleasure experience, and they have trouble feeling satisfaction from the things that healthy people enjoy.”

The article also explains that activities, people and places that become associated with the ingestion of psychoactive substances are eventually able to trigger, on their own, a cascade of dopamine into the nucleus accumbens, and thus provoke people…