The public isn't buying the idea that addiction is a brain disease, researchers found in a review of the literature.
Viewing addiction as a brain disease allows for medical treatment, behavioral interventions, and reduces stigma. Researchers who recently reviewed the literature pertaining to the prevention and treatment of substance abuse and public policy related to addiction found that more research into the brain disease model of addiction is necessary, but will require a mobilization of public support. The researchers, led by Nora D. Volkow, MD, director of the National Institute on Drug Abuse, authored the review article, which was published in the New England Journal of Medicine on January 28, 2016.
According to the authors “despite the scientific evidence and the resulting advances in treatment and changes in policy, the concept of addiction as a disease of the brain is still being questioned.” It is difficult for people to perceive addiction as a disease because the idea that drug use is voluntary is so deeply ingrained.
The review considers three stages of addiction, described by the authors as, “binge and intoxication, withdrawal and negative affect, and preoccupation and anticipation.” Dopamine is the key to the binge and intoxication stage, and it may be released in response to the environment rather than the actual substance being abused. The authors note that this is a type of “Pavlovian learning” and that the “process involves the same molecular mechanisms that strengthen synaptic connections during learning and memory formation.”
Research has shown that the withdrawal and negative affect stage of addiction works differently than previously believed. The authors say, “clinical and preclinical studies have shown that drug consumption triggers much smaller increases in dopamine levels in the presence of addiction,” which means that addicts “often become less motivated by everyday stimuli” such as relationships and activities. Interestingly, addicts themselves often cannot understand why they continue to use the drug even though it is no longer pleasurable.
The preoccupation and anticipation stage, which involves the reward and emotional signaling in the brain, is related to changes that occur in the “prefrontal brain regions and their associated circuits, seriously impairing executive processes, among which are the capacities for self-regulation, decision making, flexibility in the selection and initiation of action, attribution of salience, and the monitoring of error” according to the researchers. These changes are the reason that even when addicts sincerely wish to change are often incapable of ceasing taking the drug.
Only a small portion of people who are exposed to drugs become addicted. The authors say that “the most severe phenotypic characteristics of addiction will develop in approximately 10% of persons exposed to addictive drugs.” However, for those who do become addicts, the authors say “the neurobiologic changes are distinct and profound.”
There are examples of other diseases in which voluntary behavior contributes to disease progression, such as heart disease and diabetes, among many others. Adolescence is a particularly risky time for people who are likely to become addicts. Prevention during adolescence is critical for those who are most at-risk.
Public policies such as leaving the drinking age at 21 years of age, have the power to help lower rates of addiction because, the authors report, “the prefrontal and other cortical networks that are so critical for judgment and self-regulation do not fully mature until people reach 21 to 25 years of age.”