Dependence vs. Addiction: What’s the Difference?

By Benjamin Caleb Williams, RN

There are many tricky terms and concepts related to addiction and substance use, and their differences can often be confusing to remember. For example, substance abuse does not always mean that someone has an addiction. Similarly, some people may have withdrawal symptoms when they stop using a substance, but it doesn’t always mean they’re addicted.

Two of the most commonly confused concepts are addiction and dependence. Ultimately, dependence is the body’s inability to function correctly without the presence of a substance, while addiction is the compulsion to use a substance even when it could be harmful. These two ideas are not the same, and one can exist without the other. 

What Is Dependence?

Dependence centers around the idea of depending on something. Dependence occurs when the body requires the presence of a substance, such as drugs or alcohol, to function normally. This dependence usually develops slowly over time and happens when a substance is used heavily over a prolonged period of time.

Psychological Dependence

In the medical field, dependence usually refers to a physical process instead of a psychological one. The idea of psychological dependence, however, is a valid concept that refers to someone requiring a substance to function normally from a psychiatric perspective. Many times, psychological dependence is considered to be a type of coping mechanism.

An example of psychological dependence could be someone who drinks alcohol to calm their nerves and reduce anxiety before going into a stressful job. While this may not be psychological dependence on its own, it can turn into psychological dependence when it is not possible to cope with anxiety without alcohol. Psychological dependence occurs when the use of a substance is essential for coping with a situation or emotional state.

Physical Dependence

Physical dependence is the form of dependence typically referred to by medical professionals. Physical dependence occurs when the body adjusts its normal function to include the presence of a drug. 

This normally happens when a substance works by stimulating a receptor in the brain. Receptors in the brain require a certain level of stimulation to work correctly, and the brain will recognize when receptors are overstimulated. The brain adjusts by reducing how sensitive the receptors are. Over time, the brain begins requiring the presence of the substance in order to function normally.

Dependence is what causes withdrawal symptoms to occur when someone suddenly stops using a substance. Without the presence of the substance, the brain’s receptors will be out of balance. The brain will have to begin readjusting to the sudden absence of the drug, leading to unpleasant symptoms of withdrawal. Often, people do not know they have developed dependence until they stop using a substance and experience withdrawal.

What Makes Someone Dependent on a Substance?

Dependence occurs when the brain adjusts to the near-constant presence of a substance in the bloodstream. This usually requires heavy amounts of a substance to be used consistently for at least several weeks. However, some people may develop dependence quickly, while others may not. Because dependence isn’t obvious until substance use stops, a person may have dependence for several years without knowing it.

Signs of Dependence

The signs of dependence depend heavily on the type of substance being used. Signs of dependence only occur when going without a substance. These signs can vary from person to person but may include:

  • Headache 
  • Flu-like feeling
  • Nausea and vomiting
  • Agitated feeling
  • Depression
  • Runny nose
  • Achy joints

What Is the Difference Between Tolerance and Dependence?

People often mistake tolerance and dependence for being the same thing. Although they are closely related, they are not identical. Dependence centers around the body needing the substance to function normally, and undergoing withdrawal symptoms if you suddenly stop. Tolerance is more about the substance’s effects, and how they wane as you continue using the substance. 

As your brain adjusts its receptors to accommodate the continuous presence of a substance, it reduces the effect that the substance will have. In other words, the brain becomes tolerant of the substance, causing it to be less and less effective over time. Someone using a substance to get high will have to take more and more of the drug just to maintain the same effect. 

What Is Addiction?

Addiction describes chemical changes in the brain that are different from dependence, and these changes make it very difficult to stop using a substance. Almost all addictive substances cause the release of chemicals called endorphins in the brain. Someone who has an addiction is driven to seek and use a substance, even when it may be harmful.

What Causes Addiction?

Addiction is primarily caused by endorphins. In neurology, endorphins have been found to cause the sensation of pleasure. The brain releases endorphins whenever we are engaged in an activity that is beneficial for our health. Activities like eating something sweet, having intercourse or even watching a sunset can release endorphins. The brain uses natural endorphins to help us want to repeat an activity again.

While natural endorphins are a healthy part of life, drugs artificially release endorphins. The brain associates this large endorphin rush with drug use and tells the body that this is an action that should be repeated. Each time drugs are used, this cycle becomes stronger and more reinforced. Over time, the brain will rewire itself because of this cycle. Addiction occurs because the brain has been repeatedly wired to seek out a drug that causes the high that endorphins create.

Signs of Addiction

The signs of addiction may include physical signs of substance use and behavioral signs that occur due to social and behavioral changes caused by drug use. Signs of addiction depend on the substances being used but can include: 

  • Bloodshot eyes
  • Hyperactivity 
  • Sluggishness or tiredness
  • Difficulty holding a conversation
  • Moodiness or mood changes
  • Becoming more withdrawn
  • Changes in friend groups
  • Obsessing about using a substance
  • Using a substance even when it is causing negative effects
  • Engaging in risky behaviors
  • Legal problems
  • Financial problems

What Is the Difference Between Dependence and Addiction?

Ultimately, dependence refers to changes in the brain that cause withdrawal symptoms, and addiction refers to changes in the brain that make it difficult or almost impossible to stop the behavior of substance use. 

Dependence is caused by changes in the sensitivity of brain receptors, while addiction actually leads to rewiring of the brain. This means that dependence will go away within a week or two when using a substance is stopped, but addiction can take months or years to recover from.

How To Get Help for Dependence and Addiction

Treatment for dependence and addiction happens in two key stages, with dependence being treated before the addiction. Detox is a one- to two-week process that focuses on getting through withdrawal and allowing dependence to correct itself. Following detox, rehab focuses on recovering from addiction by learning strategies that rewire the brain and change the way people think about using substances.

If you or someone you love is struggling with addiction, mental health support is essential. The Nobu app is a great tool for improving your mental health, as it offers proven strategies and techniques that can help support your overall physical and mental well-being. Sign up for Nobu today and download the app, available for free on both Apple and Android devices.

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Edited by – Jonathan Strum Jonathan Strum graduated from the University of Nebraska Omaha with a Bachelor’s in Communication in 2017 and has been writing professionally ever since. He has written, edited and published content for health care professionals, educators, real estate agents, lawyers and high-level university faculty… Read more.

Written by – Benjamin Caleb Williams, RN

Benjamin Caleb Williams is a board-certified Emergency Nurse with several years of clinical experience, including supervisory roles within the ICU and ER settings. He obtained his Associates in Applied Science in Nursing from Cayuga Community College in Auburn, New York, then went on to obtain his Bachelors in Science from the University of Pennsylvania, majoring in Biology and minoring in Biological… Read more

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Medically Reviewed by – Dr. Angela Phillips

Angela is a licensed therapist and clinical researcher, and has worked in public, private, government, and not-for-profit organizations, across clinical and research-oriented roles. Angela’s clinical and research experience has included suicide prevention, cognitive behavioral… Read more.