Dopamine and its role in addiction

Addiction is a complex, chronic disorder where a person engages in a behavior or uses a substance compulsively, in that it provides a high incentive to repeat the activity despite the consequences. This involves a loss of control over the behavior or a substance, leading to an intense focus on obtaining it, which can often interfere with other aspects of a person’s life. According to Psychology Today, addiction can manifest in many forms, including “alcohol, inhalants, opioids, cocaine, and nicotine, or behaviors such as gambling.”

Key elements of addiction include:

Compulsively engaging in the behavior despite knowing the harmful effects and consequences
Inability to stop the behavior despite repeated attempts to do so.
Interfering with one’s life through physical or mental well-being, relationships, and overall functioning.
Increased tolerance to the behavior or substance, requiring more of it to achieve the same affect.
Withdrawal symptoms if the behavior or substance is suddenly discontinued. This can lead to a wide range of physical or psychological symptoms, such as tremors, muscle aches, anxiety, seizures, and more.

A common misconception about addictions is that they can be overcome through sheer motivation and discipline, but studies have shown that this is simply not true. It is important to note that one of the most important discoveries in addiction studies is that there is a microscopic, biological process playing out in our neurons, altering the structure and the function of the brain.

Networks of neurons, brain circuits that are responsible for coordinating and performing different functions in our body, send impulses to each other throughout the brain and spinal cord to the rest of the body through neurotransmitters that are released through the synapse, or gap, between cells. Like a key, neurotransmitters lock on to the receptors of the receiving neurons.

A key neurotransmitter affected in addiction is dopamine, which primarily functions to help you feel pleasure, motivation, and satisfaction. When a person develops an addiction, let’s say substance abuse, continued use of the substance can lead to a significant increase of dopamine in the brain’s reward pathway. The reward pathway developed as a way to reinforce the need for survival, like through eating food. Food triggers dopamine in the reward pathway and gives the person eating pleasure, motivating them to eat in the future, and therefore survive.

However, according to Yale Medicine, addictive behaviors such as substance abuse can cause dopamine to flood the brain’s reward pathway ten times more than the natural amount. With continued use of the substance, the brain progressively adapts and becomes more tolerant to dopamine, making the person wanting more and more of the substance to achieve the feeling of pleasure they felt before. Increased dopamine tolerance in addiction has been linked to more aggressive behavior, competitiveness, and a lack of self-control, along with lack of focus, problems with memory and learning, and problems with judgement.

There are three parts of the brain mainly affected by addictive behavior:

Basal ganglia: This is the reward center we talked about. Building off of the substance use example, when a drug is used, dopamine fills a section of the reward center called the nucleus accumbens. The brain remembers the pleasure of this drug and creates a craving to experience it again, and this eventually develops an addiction as the basal ganglia’s dopamine tolerance increases, increasing the desire for repetition.
Amygdala: This part of the brain helps sense fear, and helps send the adrenaline rush you feel when you go into fight-or-flight mode in stressful situations. Addiction causes the amygdala to be hypersensitive and can lead to constant feelings of depression or anxiety, tempting the person to engage in the addictive behavior for relief.
Prefrontal Cortex: This part of the brain controls our decision-making. Addictive behaviors can cause regulatory areas of the brain like the prefrontal cortex to be damaged. Just like how the liver gets damaged by too much alcohol, the prefrontal cortex can be damaged by addiction.
- Damage or decreased activity in the brain’s decision-making center will lead to the person being unable to make the decision to stop their addictive behavior, even if they realize the consequences.
- As the prefrontal cortex in children and teenagers are not yet fully developed, they are most vulnerable to addiction.

Addictive behaviors modify how the brain works and can reduce the amount of dopamine that can be released, and as tolerance increases it becomes more and more difficult to achieve the same amount of pleasure initially experienced. This can lead to reduced interest in activities, such as eating, that don’t release high amounts of dopamine like the addictive behavior. Addictions such as drug abuse can lead the amygdala to feel a heightened sense of fear or other negative emotions, compelling the person to repetitively engage in the behavior to relieve feelings of depression or anxiety.

The likelihood of becoming addicted has been linked to genetics as certain genes have been linked with certain addictions, and many addictions tend to run in families. However, there is still no definitive answer as to why some people become addicted and others don’t, according to the NIH.

According to Dr. George Koob, director of NIH’s National Institute on Alcohol Abuse and Alcoholism, “Growing up with an alcoholic; being abused as a child; being exposed to extraordinary stress—all of these social factors can contribute to the risk for alcohol addiction or drug abuse.”

That being said, it is important to begin prevention efforts as early as possible, such as by encouraging healthy lifestyles and physical activities in children, and encouraging good habits they can carry on into adulthood to help they steer away from addictive behaviors.

For more information, some of my sources for this article are linked below: