Stuck on Opioids? Learn About Telemedicine Suboxone - Insurance Accepted.

Learn More

Addiction & the Brain: How Drugs Affect the Brain

Elena Hill, MD, MPH profile image
By Elena Hill, MD, MPH • Updated Mar 25, 2023 • 4 cited sources

There is a lot of controversy around whether or not to define addiction as “a disease”. Understanding addiction as potentially a medical condition is important both to help destigmatize addiction and understand why professional treatment is usually needed for consistent recovery. 

How Is Addiction a Disease?

Addiction is a chronic condition.[1] It affects the brain’s reward, motivation, memory, and related circuitry, reinforcing a particular behavior such as use of the addictive substance. 

A person with an addiction to drugs has difficulty abstaining from drug use. They are likely to be impaired in a number of important areas, including behavioral control, drug cravings, and their ability to recognize significant problems relating to their physical and mental health. They may have significant problems in their social and work relationships. 

Addiction is generally a progressive disease, worsening if left untreated. This can easily lead to a downward spiral in a person’s quality of life and overall health. [1]

The Effects of Addiction on the Brain

Addiction can have a variety of effects on the brain that make quitting particular behavior difficult. These are some of the effects on the brain:

Reward System

Almost universally, addictive behaviors are rewarding, at least in the short term. Drugs can cause a euphoric high. This artificial reward encourages the individual to repeat the behavior over and over again. The rewarding, self-reinforcing nature of drug use can cause a cascade of other issues.[2] 

Motivational System

Drug use and other addictive behaviors alter a person’s internal motivational hierarchies, which are the ways in which we prioritize seeking out different experiences and engaging in different behaviors. Where a healthy motivational hierarchy would first prioritize what is needed to survive and maintain quality of life, drugs can cause these hierarchies to place drug use above more basic essential such as social relationship, careers, and eventually even basics such as eating, bathing and hygiene. [3]


The brain remembers behaviors a person engaged in that felt rewarding, often more deeply than we realize. It connects the specific rewarding behavior with other stimuli that were present at the time. This can cause a person to have a biological and behavioral response to external cues that may be connected to the rewarding behavior. For example, seeing drug paraphernalia may trigger a person to have cravings for the drug and put an individual at risk for returning to use. 

The Biochemistry of Addiction

The biochemistry of addiction is complex, and researchers don’t yet have all the answers.[4] However, many things are still known, and many more are strongly supported by available evidence. 

Speaking broadly, addictive drugs essentially “hijack” the brain’s reward circuitry. Drugs cause changes in the activity of reward neurotransmitter systems in the brain, self-reinforcing their use. 

Drug withdrawal also creates negative reinforcement. A person knows a negative outcome will occur if they stop taking drugs, so they are further motivated to continue using drugs.[4]

Biochemistry isn’t the only factor relevant to drug addiction but it is a critical one. Other factors include psychological comorbidities, prior emotional trauma, poor social support, inadequate coping mechanisms, etc. Drug use is multifactorial of course, but biology does likely play a significant role. 

The Disease of Addiction FAQs

How does addiction affect the brain?

Addiction affects the brain by creating euphoric feelings that then positively reinforce the behavior. Substances act on the brain’s reward system and incentive repetitive use. 

What part of the brain is responsible for addiction?

Drug use affects multiple regions of the brain Addiction impacts the brain’s frontal cortex, where it connects with key reward, motivation, and memory systems. These changes can make it difficult for a person to delay the gratification drug use brings them. Substance use also affects the hippocampus which is largely responsible for memory, as well as the basal ganglia which play a role in the dopaminergic reward system. 

Can the brain recover from addiction?

Addiction is usually considered a chronic, lifelong condition, but recovery or “remission” is possible. “Curing” addiction isn’t the goal of treatment programs since there is no “cure” for addiction. However, there are good treatments – both pharmacological and behavioral – that can keep a person in remission, potentially indefinitely.

The path to sustained recovery is not easy, but it’s worth it. Consistent effort spent working with qualified addiction treatment professionals can allow people to sustain recovery.

By Elena Hill, MD, MPH

Elena Hill, MD; MPH received her MD and Masters of Public Health degrees at Tufts Medical School and completed her family medicine residency at Boston Medical Center. She is currently an attending physician at Bronxcare Health Systems in the Bronx, NY where ... Read More

  1. Public Policy Statement: Definition of Addiction. American Society of Addiction Medicine. August 2011. Accessed January 2023.
  2. The Neuroscience of Drug Reward and Addiction. Physiological Reviews. September 2019. Accessed January 2023.
  3. Imbalanced Decision Hierarchy in Addicts Emerging From Drug-Hijacked Dopamine Spiraling Circuitry. PLOS ONE. April 2013. Accessed January 2023.
  4. The Neurobiology of Addiction: Where We Have Been and Where We Are Going. Journal of Drug Issues. January 2009. Accessed January 2023.
Safe, effective Suboxone treatment from home. Learn More

Imagine what’s possible on the other side of opioid use disorder.

Our science-backed approach boasts 95% of patients reporting no withdrawal symptoms at 7 days. We can help you achieve easier days and a happier future.