Addiction changes the chemistry of the brain in a way that deepens the hold that drugs have on a person. Some people appear to be genetically predisposed to addiction, developing a deep craving for the drug they’re addicted to.
While the addictive substance initially causes great pleasure, however, over time, neuroreceptors in the brain build up a tolerance to the chemicals, such as dopamine, that cause that pleasurable effect. As a result, when an addicted person takes drugs, their brain’s neuroreceptors become overwhelmed and don’t respond as well. In response, the person needs a greater and greater dose of the drugs to get the same pleasurable response. At this point, the cravings for the drug can be overwhelming.
When this occurs during recovery, the result is often a relapse. Your loved one may be triggered by visual reminders of drugs and feel those powerful cravings, even after weeks, months or years of sobriety. Because the body isn’t used to the drugs, however, a relapse after 90 days of clean living can mean a greater chance of an overdose.