02/25/2025
The brain disease of addiction (brief summary)
Addiction is a brain disease in which there are three areas of the brain that are primarily affected. The brain disease of addiction primarily effects three areas:
The reward center of the brain: https://pmc.ncbi.nlm.nih.gov/articles/PMC8992377/ (nucleus accumbens and ventral tegmental area);
The extended amygdala which is responsible for emotions;
The prefrontal cortex which is responsible for decision making.
Each of these areas line up with a different phase of addiction. There are three phases of addiction:
The first phase of addiction is Intoxication, and this is self-explanatory to most people. It involves the rapid rise of dopamine (and other brain chemicals including serotonin and naturally occurring opioids that result in a euphoric state) in the reward center of the brain. Once an individual develops an addiction, the rapid rise of dopamine can occur with the slightest of triggers. This rapid rise of dopamine can overwhelm the decision-making capability of the individual who has developed this brain disease.
The second phase of addiction is Withdrawal, and this is also doesn’t require an explanation to many who have experienced it. This phase primarily occurs in the extended amygdala which is responsible for emotions. Dopamine, serotonin, and naturally occurring opioids all drop to low levels during this phase, and the result is irritability, anger, shakes, sweats, and nausea. The severe withdrawal syndrome from alcohol can result in seizures and delirium tremens (a life-threatening condition that involves elevated blood pressure and hallucinations). The severe withdrawal syndrome for benzodiazepines can result in seizures.
The third phase of addiction is the Preoccupation/Anticipation phase. (also known as Post Acute Withdrawal Syndrome (or PAWS)). This is characterized by cravings, anxiety, mood swings, insomnia, and many other symptoms, and this occurs after the withdrawal phase (often a bit of a gray area). This primarily occurs in the prefrontal cortex of the brain. This is an area that is heavily involved in decision making and this area is not fully formed until the individual is in their mid-20s. This phase can last days, to weeks, to months, or even years, which is one of the reasons it is important to engage in long term treatment with therapy/counseling, meetings, and medications. If this phase is not managed appropriately, it is very difficult to maintain sobriety.
As addiction progresses, tolerance to the substance develops, and most individuals are not using the substances to get a “high”, but rather, they are using to feel “normal”. It takes more and more of the substance to achieve the desired effect. Often, to achieve the amount needed to achieve the desired effect is close to the lethal dose, which is one of the reasons for drug overdoses.
I highly recommend reading the following:
Koob G, and N. Volkow. Neurobiology of Addiction: A neurociruitry analysis. Lancet Psychiatry. 2016 August; 3(8):760-773
I recommend all articles by Nora Volkow, MD , and George Koob, PhD.
