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Addiction vs. Tolerance vs. Dependence: Is There a Difference?

substance dependence and addiction treatment

There is a very fine line between drug tolerance, dependence, and addiction. Often, it is a line that even concerned loves ones cannot fully make out. Is my son addicted to drugs, or is his body just dependent on them? Is my daughter using higher dosages to better manage her condition, or just to get high? These are questions we often hear from concerned parents, and it all comes down to this.

If a person is tolerant to, or dependent on drugs, this does mean the person is addicted. However, there is still reason for concern. Tolerance and dependence can be symptoms of substance addiction. Or, they can lead to a substance addiction in time. Let’s break this down a bit more.

What is Tolerance?

Tolerance is defined as the capacity to endure pain, hardship, or continued subjection to something, such as a drug. In the case of substance use, tolerance means that a person’s body has become less responsive to a drug or alcohol, after repeated use and exposure. In other words, tolerance is a physical effect of continued substance abuse. A person no longer gets high or buzzed from their usual dose of the drug, and may use more of the drug to achieve the same effect.

Anyone can develop a tolerance to drugs and alcohol with regular use. They can become tolerant to an illicit drug such as heroin, or to a prescription medication like Oxycontin. No matter the type, drugs and alcohol change the neurochemical make-up of a user’s brain. When these substances are used repeatedly over a period of time, the brain produces less neurotransmitters, like dopamine, in the reward circuit. This, in turn, reduces the user’s ability to experience pleasure from the drug—a sign of tolerance.

It’s important to note, however, that tolerance is not always a sign of drug abuse or addiction. Some patients with chronic pain, for example, can develop a tolerance to their prescribed pain medications, and may need an increased dosage to better manage their pain.

What is Dependence?

Dependence is defined as a physical condition in which a user’s body has adapted to, and become reliant on, the presence of a drug. It is caused by constant, prolonged exposure to a substance. When a person stops taking that drug suddenly, they will experience uncomfortable withdrawal symptoms.

Like tolerance, dependence is a physical effect of drug abuse, and is related to the way drugs impact the brain. When a person uses drugs repeatedly, the chemical make-up of their brain is altered. They become reliant on the drug to feel good, or in more severe cases, to function normally.

When the body is dependent on a substance to function, a person needs to be weaned off the drug gradually, rather than all at once (a process called tapering). This helps to avoid the discomfort of withdrawal, and the dangers that can come with quitting drugs cold turkey.

While addiction and dependence are often used interchangeably, people who are dependent on a drug are not necessarily addicted. Non-addictive drugs can also cause physical dependence in an individual. For example, Prednisone – the drug used to treat asthma and allergic reactions – is not addictive, but can cause withdrawal symptoms if a user suddenly stops. There are also acute and severe cases of dependence. Those who are dependent on coffee, for example, may experience very acute withdrawal symptoms without that morning cup of Joe (a headache, for example). Meanwhile, those dependent on opioid drugs may experience a life-threatening withdrawal syndrome. 

What is Addiction?

Substance addiction is a chronic disease that, like tolerance and dependence, is caused by repeated misuse of drugs or alcohol. Those with a substance addiction continue to use drugs and alcohol, despite the harmful consequences, and have great difficulty stopping. According to the National Institute on Drug Abuse (NIDA), addiction is considered both a complex brain disorder and a mental health disorder, and is the “most severe” on the full spectrum of substance use disorders.

The most tell-tale symptom of substance addiction is compulsive, drug seeking behavior. An addicted individual will have constant, uncontrollable drug cravings and will spend much of their time seeking, using, and recovering from the drug. Those struggling with addiction also struggle to fulfill other obligations (work, school, social, or family) due to their persistent patterns of drug abuse. 

Today, clinicians stay away from the term “addiction” and use the diagnosis, “substance use disorder.” A substance use disorder means a person is medically and functionally impaired or distressed, due to their drug use. It is characterized by symptoms such as compulsive cravings, inability to control drug-seeking behaviors, continued drug use despite negative consequences, high tolerance, and withdrawal symptoms. You can learn about the definition of a substance use disorder here.

Addiction vs. Tolerance vs. Dependence: What’s the Difference?

Substance addiction is often associated with symptoms of tolerance, dependence, and withdrawal. Those who are addicted may have built up a tolerance to their drug of choice. They may be dependent on the drug to function, and may experience painful withdrawal symptoms when they stop use. All this said, however, addiction is very different in that it is more than physical. 

Tolerance and dependence are characterized by physiological changes, and manifest in physical symptoms. Substance addiction, on the other hand, is a complex disease, affecting an individual more holistically. It is a mental illness that causes disruptions in a user’s behavioral and mental health. It changes a person’s priorities and reduces their self-control. 

Those who are dependent on or tolerant to drugs may not be addicted. For example, one can easily become dependent on prescription painkillers (like Oxycontin) over a scheduled period of time. They may experience negative side effects after stopping the drug use. However, when the individual is addicted to painkillers, they will misuse the substance. They may take the drug even when there is no pain. They may use the drug longer than prescribed, or may use higher dosages to feel the euphoric effects. They may order multiple prescriptions, or call multiple doctors, to try and obtain more of the drug. They will not be able to control their body’s need (i.e. compulsive cravings) for the drug, and will do what it takes to keep using.

Tolerance and dependence are useful indicators of drug use, and as you may have presumed, can be precursors to addiction. When a person has a tolerance to their drug of choice, they may decide to use more and more of the drug to feel its effects. The higher the dosage, the higher likelihood of developing an addiction. This is also true for dependency. A person will often become dependent on a drug before it takes over their mental and emotional state, and they become addicted.

While substance addiction (or a substance use disorder) is the most severe of the three conditions above, every one can be a cause for concern. If your son is using drugs longer than prescribed, if your daughter is increasing her prescription dosages at home, or if your friend is using drugs despite the negative consequences in his or her life, these can all be signs of addiction.

If you are concerned for your loved one’s health, please do not hesitate to seek help. You can call Turnbridge at any time to learn more about the signs of addiction and our treatment programs. It is never too early to seek help for a drug problem, but it can be too late. Call 877-581-1793 today.