Several years ago, I was attending a meeting at the rehab center where my son was a patient. The meeting was open to loved ones of the patients. During the question and answer session, a parent started to ask a question and began by saying, “My daughter won’t stop …” The counselor in the meeting interrupted and said, “You mean your daughter can’t stop.” The woman proceeded to ask her question, replacing “won’t” with “can’t”.
At the time, I wondered if that is really true. Is it true that someone suffering from Substance Use Disorder may want to stop, but cannot? And, if it is true, then how do we explain the fact that some people do indeed recover.
That led me to a quest to understand what really happens in the brain when someone is addicted – as well as I could, not being a medical person. This post summarizes my understanding. Much of this post came from the training class at https://learning.overdoselifeline.org/courses/the-brain-and-the-disease-of-addiction and from the book The Opioid Epidemic – What Everyone Needs to Know.
The American Society of Addiction Medicine defines addiction as follows: “A primary, chronic disease of brain reward, motivation, memory, and related circuitry. Dysfunction in these circuits leads to characteristic biological, psychological, social and spiritual manifestations. This is reflected in an individual pathologically pursuing reward and/or relief by substance use and other behaviors.”
To understand the impact of addiction, I found we need to first understand components of the brain:
- The frontal lobe includes the pre-frontal cortex (PFC) which manages self-control, planning, decision making, and problem-solving. The PFC receives sensory information, plans responses, and communicates with other areas of the brain to enact a response.
- The parietal lobe affects sensations from muscles and skin.
- The temporal lobe is involved in retention of visual memory, language comprehension, and emotion association.
- The occipital lobe affects vision, image, recognition, and perception.
- The cerebellum controls motor function, balance, coordination, and posture.
- The brain stem controls alertness/sleep, blood pressure, breathing, digestion, heart rate, swallowing and temperature.
- The cerebellum and brain stem are part of the hind brain, which is also called the reptilian brain, which controls working memory, sleep, and arousal. The reptilian brain controls our survival instincts.
- The limbic system controls emotions, instincts, memory, and the brain’s reward pathway. The nucleus accumbens is in the limbic system, which is where dopamine is released. Endorphins or endogenous opioids, which are the body’s natural opioids, trigger the release of dopamine, such as after a great meal, during an exhilarating run, and at the moment of orgasm.
- The amygdala prepares the body for emergency situations. It is responsible for flight or fight response, instinct, and for storing memories of events.
- The hippocampus converts things that are in your mind at the moment into things you will remember in the long run – long-term memory.
The brain’s reward pathway helps us avoid painful or harmful experiences and to make us feel good when we do things that are necessary for our survival. It takes and provides information from other parts of the brain.
Our Brain Tells Us To Do Whatever Releases Dopamine
Our brain decides what to do based on what releases dopamine. Dopamine is released when the brain recognizes that something is good for our survival. It is what causes us pleasure. A release of dopamine tells the brain that whatever caused the release is good for you and should be repeated.
Drugs flood the brain with dopamine, and drug use reduces the brain’s ability to produce dopamine on its own. More drugs are required, which is reliance and tolerance. The ability to exert self-control becomes impaired. Areas outside the reward pathway are also affected: judgement, decision-making, and memory.
Hardwiring means connections between neurons are pruned back in some areas, and in other areas, neurons form more connections. Neuron connections and pathways that link drug use with reward increase in size and strength, making drug-seeking behavior habitual. The brain has been “rewired” to think that use of the substance is more important than food, water, sleep, and interaction with others.
Withdrawal and Relapse
Withdrawal happens when the substance is no longer available. The acute stage of withdrawal lasts a few days. The post-acute stage has symptoms like anxiety and restlessness, and can last for several years.
The brain stores information about environmental cues that caused the release of dopamine. The memories create a craving when the patient comes across those environmental cues. Visiting the street corner where you bought heroin may produce a craving even after years of sobriety.
The flooding of the brain with dopamine causes the hippocampus to store a memory of the intense satisfaction. With repeated exposure, nerve cells in the nucleus accumbens and the pre-frontal cortex tell the brain that the substance is required. So, even after withdrawal and the reduction of physical dependence, the patient’s memory tells him to do it again.
So, why does the patient relapse even after withdrawal, when there is no longer a physical dependence? And why doesn’t the PFC that is responsible for judgment and decisions keep him from doing so?
One of the reasons may be related to age. The brain matures from back to front, so the PFC is the last to mature and doesn’t fully mature until age twenty-five. Someone exposed to opioids before the PFC is mature is less likely to be able to avoid relapse. Another factor may be the patient had abnormalities in the PFC to begin with.
Another factor may be damage drug use has done to the PFC itself and its ability to communicate with the rest of the brain. Drug use causes dendritic spines, which facilitate communication, to dissipate. Their loss creates difficulties reasoning and making decisions, causing limited ability to resist cravings.
Neuroplasticity and Recovery
When the drug is removed for some time, the brain can rewire and recover to a small or great degree, depending on the patient and the severity of the addiction. Neuroplasticity is the brain’s ability to change. All of our brains grow and adapt. Drug use causes structural changes. We discussed above how it can rewire to brain to be addicted. It can also rewire to become more normal after extended period of no substance use. However, opioid addiction is a chronic illness, meaning there is no cure, and there is always a risk of relapse.
Some people are able to stop on their own, just like some people with diabetes and cancer may get better, even without treatment. For all diseases, recovery without treatment is rare.
Like any disease, there are different degrees of severity of addiction. Understanding a little more about what happens in the brain convinces me that neither “won’t stop” or “can’t stop” is correct. Willpower plays a role, but in most cases, it is not sufficient to stop, given the changes that drug use has made to the brain. Perhaps the best phrase is, “has not yet been able to stop.”