The biggest question surrounding drug and alcohol use has been who or what is to blame for the disease of addiction. Were the drugs themselves responsible, possessing qualities that made it impossible for people to resist them? Or were certain individuals simply weak, engaging in self-destructive behavior because they enjoyed it and didn’t really want to stop?
We now know that addiction is a chronic brain disorder and not simply a behavioral problem involving too much alcohol, drugs, gambling or sex. When people see compulsive and damaging behaviors in friends or family members, they often focus only on the behaviors as the problem. However, these outward behaviors are actually manifestations of an underlying disease that involves various areas of the brain, according to the American Society of Addiction Medicine.
This brain disease model of addiction is now the most widely accepted theory about the nature of addiction. This theory doesn’t let users off the hook, but rather explains how certain drugs interact with the human brain, leading some individuals to develop an addiction disease.
The disease model did several important things to the study and treatment of addiction. First, it explained why addictive substances do not affect everyone in the same way; for example, why the majority of people who consume alcohol will not become alcoholics. It also placed addiction treatment and recovery under the umbrella of medical care, encouraging the treatment of addicts as patients rather than malefactors. Lastly, the addiction model went a long way toward explaining why certain drugs have addiction potential, and why others have little or no potential for addiction.
The brain disease theory of addiction states that individuals become addicted to certain substances when the chemicals introduced to the brain by that substance succeed in rewriting the brain’s chemistry. Specifically, these substances rewrite the chemistry of the limbic system, which is the part of the brain responsible for mood and reward feedback. This change in brain chemistry causes the brain to expect certain levels of addictive substances to be in the system in order for it to function properly. Without the substance to which they have become addicted, individuals will experience severe cravings and go into withdrawal as the brain struggles to function without the drug.
With an addiction, the presence of a certain substance in the brain becomes the new “normal.” The limbic system has been reprogrammed to regard the presence of the addictive substance and the body’s reaction to it as the status quo, and cravings can only be satisfied temporarily until the substance is metabolized and its presence in the brain once again drops. Addicts are no longer able to choose not to use, because their bodies now rely on the substances in order to function properly.
As the “pleasure center” of the brain, it is easy to regard the limbic system as frivolous component of our central nervous system. However, the limbic system is actually critical to our survival. The purpose of the limbic system is to identify elements that promote our survival, and to encourage us to continue to seek out those elements with the release of dopamine.
Because the limbic system is the primary home of the addiction phenomenon, it makes sense that addictive drugs are those that affect the limbic system more rapidly and more directly than other substances. Highly addictive drugs quickly cause a rapid surge of dopamine to be released by the limbic system, in larger amounts than those to which the brain is accustomed. Certain substances can cause the release of up to 10 times the amount of dopamine than the brain normally experiences.
Since dopamine is the chemical that makes us feel happy, individuals are often tempted to use such drugs more than once, even before they become addicted. However, dopamine is a chemical that our brains are naturally programmed to seek out, and rapid spikes in the levels of dopamine in the system quickly convinces the brain that this substance is an important part of survival. Furthermore, the extremely high levels of dopamine released cause the brain to prioritize. At that point, the addicted brain is no longer seeking pleasure—it is seeking normalcy.