When someone is addicted to a substance, it’s not uncommon for their loved ones to refer to them as having an “addiction” to certain behaviors or describe them as someone that is “dependent” on alcohol or drugs. People tend to use the words “addiction” and “dependent” interchangeably to describe a person’s behavior when engaged in a certain activity, as well as the results of the behavior when it leads to a physical illness. However, there are clear differences between the two terms, several of which deal with the chemical effects that happen to addicted persons.

Let’s examine how the world views addiction versus dependence in relation to substance abuse disorders.


In the substance abuse world, defining addiction is fairly clear. A person with an addictive temperament is generally using a drug or alcohol consistently to excess. This addictive behavior can be personally destructive to a person. Over time, addicts start to lose not only their jobs, homes, and money, but also friendships, family relationships, and contact with the normal world. Addicts have a desperate view of the world, in which the only priority is securing the next high.

Psychology Today defines addiction as an activity initially enjoyed by a person (eating, drinking, drug-taking, etc.), but with repeated use and higher amounts needed to achieve a similar ‘high’ that can become life-threatening for the person’s level of work and life responsibilities.

Medical and substance abuse communities have found that there are neurochemical differences between a normal brain and an addict’s brain. There are even perceived differences between addiction versus the abuse of a substance. A person who is chemically dependent on a drug might show different physiological changes around chronic usage, tolerance levels, and even withdrawal symptoms.

Studies have shown that addiction can form in individuals through a combination of genetic makeup and poor social skills. This is why the offspring of addicts are prone to becoming addicts. One study showed that a child of a parent with a drug or alcohol addiction is eight times more likely to develop an addiction as well.


‘Dependence’ is a term used to describe a person’s physical and psychological loss of control due to substance abuse. If a person uses many drugs and develops a physical dependence on these drugs, that person is usually described as dependent. That alone isn’t always an addiction, but it can accompany addiction.

Sometimes, it’s hard to tell the difference. For instance, someone who is on a prescription for pain medication may find that he needs increasing amounts of dosage for the medication to work. Some doctors may diagnose this as an increasing tolerance, or it might be disguised as the possible start of an addiction issue.

The difference between dependence and addiction

In traditional diagnoses, ‘addiction’ generally referred to a person’s physical reliance on alcohol, drugs, and other substances and behaviors, while ‘dependence’ was viewed more as the psychological reliance on addictive behavior. It’s a scenario that pits addiction versus abuse or addiction versus dependence. But increasingly in recent years, that view has flip-flopped a bit.

Today, medical experts refer to ‘dependence’ usually around a person’s constant drug and alcohol abuse. Conversely, chronically addictive behaviors like compulsive sex, constant gambling, and even non-stop Internet usage can be seen as an ‘addiction.’

The World Health Organization uses a definition of ‘dependence’ that describes a collection of different characteristics that grow to become a much higher priority in a person’s life than other previous behaviors that were more important at one time. Consider the case of an emerging marijuana smoker or pill-taker. At first, starting this behavior is an extra activity, but as the user becomes more dependent on the high, it can turn into the main activity. This is where dependency can turn into full-blown addiction—when substance abuse becomes the all-encompassing main priority.

Does tolerance lead to dependence?

The National Institute on Drug Abuse notes that tolerance occurs in a drug or alcohol user when the user needs more of the drug or alcohol to get the same effect that occurred during the initial periods of intake. It’s a grim scenario that unfortunately is found in many drug abuse cases year after year.

The recent death of pop star Prince from an opioid overdose was one of the 25,000 fatal opioid overdoses in the US every year. What these opioid overdoses show, according to an article in Scientific American, is how increased tolerance of the drug can lead to higher chemical dependence on the side effects. The pain-killing effects of the drug bring about higher tolerance levels. And as the user takes higher amounts to feed this side, the secondary effects of respiratory depression (slowed down breathing or lack of breathing) and breathing are doubled or tripled. It is in this so-called differential tolerance where the users usually overdose.

Chemical dependence certainly occurs with higher tolerance levels. Dependence situations demand the need for skilled therapists, counselors, and medical practitioners. Reach out to our staff at The Recovery Village to learn more about how we treat substance issues, chemical dependency, and behavioral addiction.


“Dependence syndrome definition.” World Health Organization. No date shown. Accessed Aug 14, 2016.

Family History and Genetics.” National Council on Alcoholism and Drug Dependence. April 25, 2015. Accessed August 15 2016.

“What is Addiction?” Psychology Today. No date shown. Accessed August 15, 2016.

The Neurobiology of Drug Addiction.” National Institute on Drug Abuse. January 2007. Accessed August 15, 2016.

Hayhurst, Christina J. and Durieux, Marcel E., “Opioid Overdose: The Price of Tolerance.“, Scientific American, August 9, 2016. Accessed August 15, 2016.

Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.