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How the Brain Reacts to Drugs—Why Addiction Happens

According to data collected by the National Survey on Drug Use and Health, about 20.3 million people age 12 and older had a substance abuse disorder in 2018. A staggering 1 in 5 people 12 and over had used an illicit drug in the past year, and slightly over half of Americans 12 and over reported drinking alcohol. It’s clear that we’ve got a substance abuse problem in this country, and it’s taking a toll, not just on individuals, but on our nation as a whole. How have we reached this point? What’s the explanation for the prevalence of addiction? There’s no one answer to this question because no two people struggling with addiction are the same. What’s certain, though, is that the way the brain reacts to drugs is a major factor in how and why addiction happens.

The first thing to understand about addiction is that a common thread between drugs of abuse is that they alter the brain’s mesolimbic pathway. This is a brain circuit dependent on dopamine, a neurotransmitter that plays a role in how people feel pleasure. Because of this, the mesolimbic pathway is also called the brain’s reward pathway. Different habit-forming substances impact this circuit differently, but whether it’s direct or indirect, they all have an effect.

At first, dopamine is emitted in response to addictive substances, and the person feels good. It was once believed that dopamine surges caused euphoria, but the current thought is that it plays the role of reinforcing drug use. A surge of dopamine is released during a pleasurable experience, signaling that something important is happening and should be remembered. This signal changes the neural connectivity in order to make it easier to repeat the activity, and this leads to the formation of habits. Because drugs produce larger surges of dopamine, the brain learns to seek drugs instead of other, healthier sources of enjoyment. Things in a person’s daily routine or environment that are connected with drug use can become cues that trigger cravings, even if the drug is not available, and this reflex can last for many years. As a result, people who have been drug-free for many years can still experience cravings when they return to a place where they used to use drugs.

Ironically, with prolonged use of addictive substances, the brain adjusts to dopamine surges by reducing the production of dopamine as well as the number of receptors that process it. Soon, the person has a hard time experiencing any kind of pleasure at all. That’s why drug and alcohol abusers often become depressed and unable to take an interest in things they used to enjoy.

The brain is physically altered by drug and alcohol abuse. It actually shrinks, and the parts of the brain that regulate stress management, impulse control, and the processing of information can be damaged. Parts of the brain affected by drug use include:

  • The basal ganglia: These areas are part of the reward circuit and are over-activated by drug use.
  • The amygdala: Sometimes called the emotional center of the brain, the amygdala processes stressful feelings like anxiety, irritability, and unease. Increased drug use can cause this circuit to become oversensitive to stress, resulting in extreme mood swings and a constant state of panic, worry, and fear. People may then seek out drugs to alleviate these feelings.
  • The prefrontal cortex: This part of the brain powers problem solving, decision making, and impulse control. It matures late, which is why teenagers are most vulnerable to drug addiction. When the balance shifts between this circuit and the reward and stress circuits, a person with a substance use disorder seeks drugs compulsively, with little impulse control.

Of course, not everyone becomes addicted to substances. It’s hard to predict who will become addicted because there are several risk factors at play, including genetic, developmental, and environmental factors. The good news? Even if a person’s brain has been damaged by drug addiction, that damage can be reversed. Abstaining from addictive substances can reverse physical changes, combination therapies can help manage the physiological effects of addiction and withdrawal, and cognitive-behavioral treatment can help repair the psychological damage. Changing behaviors and finding healthy ways to satisfy cravings can actually correct damaged brain function.

If you or someone you love is struggling with addiction, BriteLife Recovery is here for you. A one-on-one approach to addiction recovery is at the heart of BriteLife’s philosophy, and it’s key to the success of the program. Individual therapy can give patients tools and help them find the strength they need to survive addiction, gain new coping mechanisms, and rebuild their lives. If you know someone who you think would benefit from the BriteLife approach to addiction recovery, visit our website to learn more. You can also find us on Facebook or follow us on Twitter to find out how we can help.

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