Geisinger Preventive Medicine Lecture Series: “The New Neurobiology of Addiction”
Lecture Type: Online Video (Link Here)
Time: 55 minutes 24 seconds
Date: October 8th, 2016
Speaker: Dr. Petros Levounis, MD/MA
Topic: Neurobiology of Addiction
Introduction
In “The New Neurobiology of Addiction”, part of the Geisinger Preventive Medicine Lecture Series, Dr. Petros Levounis reviews the history and science of addiction. He explains the current neurobiological understanding of addiction, as well as the history of the opioid epidemic in the United States. This includes the major areas in the brain involved in addiction and how the anatomy makes it so difficult to stop behaviors that we are addicted to. He goes on to discuss new concepts that are being developed in understanding addiction and how this can be used to improve current treatment protocols. Scroll down to read more or click the link above to view the video yourself!
Addiction
Addiction is a complex process. There are four major influences that Dr. Levounis explains turns the brain switch of addiction on. There influences are:
- Biological
- Psychological
- Social
- Use/Exposure
Biological factors include genetic predisposition, such as those that have been linked to alcoholism. Psychological factors include trauma or disorders like binge-eating. Social factors include the environments and communities in which we live. Finally, exposure includes whether a person engages in the addictive behavior to begin with. For example, even if a person has none of the other biopsychosocial factors, when a person smokes a cigarette they have a greater likelihood of becoming addicted to smoking.
Basic Neurobiology of Addiction
Dr. Levounis discusses that are three major brain centers recognized in the process of addiction. These include the:
- Hippocampus
- Limbic System
- Nucleus Accumbens
First, the nucleus accumbens has a major role in the reward pathway of the brain, called the mesolimbic dopamine pathway. In response to a pleasurable activity, the ventral tegmental area (VTA) of the brain releases the neurotransmitter dopamine onto the nucleus accumbens. This reinforces a behavior. For example, when you eat a delicious meal dopamine is increased 100% from your baseline level, which results in feelings of pleasure. The same occurs for sex, but this release dopamine about 200% your baseline level. In essence, dopamine is released every time something feels good.
Second, below the nucleus accumbens is the hippocampus. This is the memory center of the brain. The proximity to the mesolimbic reward pathway is significant to addiction because it makes it, in a sense, stores the addictive pathway you create. Even after years of being sober, the brain remembers the addictive behavior. For example, a person who smoked two packs of cigarettes a day quits. They are sober for 20 years. One day, they decide to smoke one cigarette due to a stressful situation at home. They think it will only be a one-time thing; however, after only a few days they are right back to smoking two packs of cigarettes a day as they did 20 years ago. The hippocampus plays a large part in making it difficult to fully quit an addictive behavior.
Finally, Dr. Levounis discusses the importance of the limbic system, or the emotional system of the brain. The limbic system actually includes the hippocampus, as well as the amygdala, hypothalamus, and other centers in the brain. This adds to addictive behaviors by pulling-in people’s emotions beyond the feelings of pleasure. This, again, makes it difficult to quit the behavior of concern.
Other Brain Centers
There are two other brain centers that Dr. Levounis explains in relation to addiction. The first is the frontal lobe. The frontal lobe is the center of planning, cognition, and rational thinking. This center directly opposes the hijacked pleasure-reward pathway in addiction. The second is the insula, or the area of the brain that is engaged in interoception, or self-perception. This center chooses what to focus on in the body. For example, if you are reading this article, you may be sitting there with the need to go to the bathroom, however, you do not realize it until you read this sentence. This is your insula at work! It chooses what body sensations to focus on and then creates a meaningful interpretation of them.
The Opioid Epidemic
In the United States, there has been a long-standing epidemic of addiction to pain killers called opioids. In a 1970 letter to the editor of JAMA, a medical journal, there was a statistic that 4 out of 12,000 people prescribed opioid medication become addicted. Physicians used this statistic to inform prescribing opioids for any relevant pain that a person presented to clinical encounters with. This information was wrong.
Remember how sex increased dopamine levels in the brain by 200%? Research later discovered the amphetamine, a type of pain killer, increased baseline dopamine levels by 100%. Dr. Levounis discusses that other medications even increased this level to between 4000 and 5000%. In other words, it hijacked the natural reward pathways in the brain to create an addiction to these medications.
When medical institutions became aware of the mistake made in prescribing pain medications, safeguards were put into place to limit prescriptions. It was too late. Individuals sought relief of pain in the form of heroin and later fentanyl. Each substitute required a smaller and smaller dose to cause death and mortality increased. Dr. Levounis shared the picture below showing how much of each compound, heroin, fentanyl, and carfentanil, it takes to kill a person.
Treatment
Despite the complexity of addiction, there are ways that people can seek help. These include medications, counseling and psychoanalysis, and group therapy sessions, like Alcoholics Anonymous (AA). In combination, it increases the success that a person has with stopping the addiction and controlling the behavior of concern throughout their lifetime. Dr. Levounis goes into particular methods used by medical providers for each of these, such as motivational interviewing, that increase the success of these therapeutic modalities.
One slide, taken from Goldfarb (1996), is interesting to note in Dr. Levounis’ discussion of treatment. In this study, patients and medical staff were asked to rank the importance of different factors in treating addiction. In the image below, we can see that medical staff ranked AA at the very bottom of their list in importance to help treat addiction. However, the patients listed AA as the fourth most important factor in their recovery. Additionally, when medical staff were asked to create a rank according to what they think their patients would rank, AA was sixth on the list. Therefore, Dr. Levounis suggests that this shows a major disconnect between attitudes of medical staff and patients in regards to their treatment.
Lastly, mindfulness is growing in popularity to treat addiction. The basis of mindfulness training is to use the insula, the center of the body that creates meaning out of bodily sensations, to create awareness of the drive for an addictive behavior. The metaphor used by Dr. Levounis in his lecture is very helpful in understanding this. Think of a craving for drugs as a suitcase in an airport. Mindfulness makes you aware that you have this suitcase, but that you also have a choice. You can either pick up the suitcase, meaning you use drugs, or you can leave the suitcase where it is. You accept the sensation of cravings but do not act on them. This suggests that we can train the insula to preferentially ignore the craving for drugs.
Closing Thoughts
This article does not do justice to the amount of information conveyed by Dr. Levounis in his lecture on the neurobiology of addiction. I highly recommend watching the video for yourself to learn more about the history of the opioid epidemic, current and upcoming models of addiction, and how addiction in treated in clinical settings. Use the link above, or the citation below, to watch the lecture yourself!
Citation
Levounis, P. (2016, October 8). The New Neurobiology of Addiction.” [Lecture Recording]. Geisinger Commonweath Preventive Medicine Lecture Series in partnership with WVIA. https://on-demand.wvia.org/video/the-new-neurobiology-of-addiction-uxknjc/
Disclaimer
This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of medical advice or treatment from a personal physician. All viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. The publisher of this content does not take responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement, exercise or other lifestyle program.