Addictions are chronic, relapsing brain diseases that manifest themselves in three distinct phases: craving for the object of addiction, loss of control over its use and continued involvement with it despite harmful consequences. Over time, addiction can change both brain structure and function. Just as diabetes impairs the pancreas and cardiovascular disease damages the heart, addiction ‘hijacks’ the brain and even destroys key brain regions that are meant to help us survive. Similar to other chronic diseases, addiction cannot be cured. However, its severity can be reduced and/or controlled with appropriate medical treatment.
A healthy brain rewards healthy behaviors – such as exercising, eating, or bonding with loved ones – by switching on brain circuits that make us feel wonderful, further motivating us to repeat those behaviors. In contrast, when we are in danger, a healthy brain pushes the body to react quickly with fear and move out of harm’s way. If we are tempted by something questionable – such as gambling with money we don’t have or buying things we can’t afford – the front regions of the brain help us decide if the consequences are worth the actions.
But when we are becoming addicted to a substance, that normal hardwiring of helpful brain processes can begin to work against us. Drugs or alcohol can ‘hijack’ the pleasure/reward circuits in the brain and hook us into wanting more and more. Addiction can also send the emotional danger-sensing circuits into overdrive, making us feel anxious and stressed when we’re not using the drugs or consuming alcohol. At this stage, we often use drugs or alcohol to keep from feeling bad rather than for their pleasurable effects.
To compound that, repeated use of drugs can damage the essential decision-making center at the front of the brain. This area, known as the prefrontal cortex, is the very region that should help us recognize the harms of using addictive substances.
“Brain imaging studies of people addicted to drugs or alcohol show decreased activity in this frontal cortex,” says Dr. Nora Volkow, director of NIH’s National Institute on Drug Abuse. “When the frontal cortex isn’t working properly, people can’t make the decision to stop taking the drug – even if they realize the price of taking that drug may be extremely high, and they might lose custody of their children or end up in jail. Nonetheless, they take it.”
The National Institute on Drug Abuse (NIDA) describes addiction as the most severe form of a Substance Use Disorder (SUD).