Addiction, also referred to as a substance use disorder (SUD), is a brain disorder in which the body must have a substance in order to avoid physical and psychological withdrawal symptoms. It is characterized by symptoms of craving, loss of control, and a compulsion to continue the substance use despite the consequences. Some consequences could include losing their job, losing friends, or getting in trouble with the law. SUDs can affect anyone regardless of their demographics such as income, age or race.
Substance use disorders are considered a disease by leading medical authorities such as the American Medical Association and the American Society of Addiction Medicine because they are caused by a combination of behavioral, environmental, and biological factors, and they adversely impact the functioning of the brain and the body. While other diseases might affect the heart or the kidneys, in the case of SUDs, the brain is the organ that is primarily affected. SUDs occur in a continuum and can fluctuate over time, but as they become more severe, they can become life threatening and require medical attention.
Image credit: McGill University 2018
All drugs that can be misused, from nicotine to heroin, cause a powerful spike of dopamine in the brain, making it hard for the brain to ignore. Although opioids can affect people differently, most people who become addicted to opioids report feelings of euphoria and relaxation. Over time, this ‘high,’ combined with the surge in dopamine that tells the brain to continue repeating the behavior, rewires the reward system of the brain so that a person will continue to crave, seek out and use an opioid despite negative consequences.
As a person uses opioids with more frequency, their body will become so used to the substance that they actually have to take more of the drug to get the same effects. This is called tolerance. As tolerance builds, it becomes harder and harder to stop using a drug because a decrease in use will lead to symptoms known as withdrawals. In the case of opioid use disorder, withdrawals are often described as feeling like the worst flu one could imagine, including vomiting, diarrhea, muscle aches, abdominal cramping, excessive sweating, racing heartbeat, high blood pressure, runny nose, and inability to sleep. For most people who experience a severe opioid use disorder, they reach a point of opioid use in which they no longer experience euphoria when they use; they are simply using opioids to avoid feeling sick from withdrawal symptoms.