Addiction, whether it be substance or behavioral, has long been misunderstood by researchers, and only recently has the scientific consensus among medical professionals changed. When study into the cause of addictive behavior first began in earnest in the 1930s, investigators believed that addicted individuals were morally inadequate or lacking in willpower.
Since then, however, the scientific community has changed its views on addiction, now recognizing it as a chronic disease that physically changes the brain in both structure and function. The root of addiction is a shortcut or hijacking of the brain’s reward system by means of floods of neurotransmitters, like dopamine.
How addiction manifests in the brain
The word “addiction” is derived from a Latin term for “enslaved by” or “bound to.” If you or someone you love has ever been an addict, you can surely understand why.
Addiction has a powerful influence on a person’s brain that manifests in a variety of ways. The disease is characterized by cravings, loss of control, and continuing involvement with the object of addiction despite adverse consequences.
Recent imaging technology has had a massive impact on how we understand the manifestation of addiction in the human brain. With these new imaging techniques, researchers can actually watch the effects of addictive substances or behaviors on the brain’s neural circuitry.
The standard manual for diagnostics in the United States, the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (or DSM-IV) describes multiple addictions, each tied to a specific substance or activity. However, the recent consensus is emerging that these may represent multiple expressions of a common underlying brain process happening in the brain’s reward system.
The brain’s reward system
The brain’s system of reward-related learning plays an important role in our collective human survival, linking activities like eating and reproducing with pleasure and reward. The reward circuit also includes aspects of memory and motivation, linking them both to pleasure and reward — thereby creating a self-sustaining motivation-reward framework.
When a person engages in an activity that they find pleasurable, a specific set of neural circuits known as the brain reward system are activated. This beneficial pathway, however, can become hijacked by powerful substances or behaviors that misuse the brain’s circuitry and abuse its function.
A hijacked reward system
Everything we know about addiction suggests that addictive substances and behavior coopt these neural mechanisms. According to current theories about addiction, dopamine interacts with glutamate, another neurotransmitter, to appropriate the brain’s system of reward-related learning.
The brain registers all pleasures in the same way, whether they be a psychoactive drug, money, sex, or delicious food. The distinct chemical signature we can see for this process is the release of the neurotransmitter dopamine in the nucleus accumbens, a cluster of nerve cells lying underneath the cerebral cortex. This area of the brain has been called the “pleasure center” because of the consistent association with dopamine release in response to pleasure.
Addictive substances and behaviors create a shortcut, hijacking, or short-circuiting of this reward system by flooding the nucleus accumbens with dopamine. The hippocampus then reacts, creating memories of this instant gratification, and lastly, the amygdala creates a conditioned response to the specific stimuli.
Substance addiction
Natural rewards typically come to us only with time and effort. Addictive substances, however, provide a mental shortcut to this feeling, saturating the brain with dopamine and other feel-good neurotransmitters.
For example, addictive drugs actually release 2-10 times the amount of dopamine that natural rewards do, and far more quickly at that. This causes an addicted person’s brain receptors to become overwhelmed.
Without a way to withstand this deluge, over time, the brain actually adapts to the overwhelming flood of dopamine, making the addictive substance less pleasurable.
Behavioral addiction
For many years, experts believed that only alcohol and powerful drugs could cause addiction but the consensus on this has shifted as well. There are many addictive behaviors out there but gambling is a good example of a powerful behavioral addiction that affects millions of people around the world.
Just like with substance abuse and addiction, repeated exposure creates a process that couples liking something with wanting it, in turn driving us to go after it. Gamblers have a compulsion to keep playing and a built-up tolerance to ignore losses and associated misfortune.
There are methods that gamblers can use to limit their losses, but considering their reward system is already in a state of disarray, it’s nearly impossible for them to put these methods into practice.
Addiction and mental health
An individual’s mental health includes their physical, emotional, and psychological well-being and affects how they interact with the world around them throughout all stages of life. The importance of mental health cannot be minimized, as it truly helps determine how well we handle stress, make choices, and relate to others.
Addiction hijacks the motivation center and brain reward system of an individual, compromising the mental well-being and deeply affecting their lives. Although we do not yet have the tools to remove the long-lasting brain changes that govern addiction, with ongoing treatment and a variety of therapeutics, this complicated disease can be overcome.
