Substance use disorders are complex and may come in different stages and varieties. Some words used to describe it are thought to be synonymous, but that actually describes different things. Two of these terms are dependence and addiction. They are closely related, but they actually mean two different things and affect your brain and body differently. Learn more about dependence, addiction, and how they are related.
Dependence, or chemical dependence, is the biochemical consequence of your body adapting to the presence of a drug in your system. Psychoactive drugs interact with chemical processes in your brain and body by altering your chemical messaging system. Different drugs do this in different ways. Some mimic naturally occurring chemicals like opioids, which are very similar to your endorphins. Others increase the release or prevent the reuptake of certain natural chemicals like stimulants that can affect dopamine. Drugs like alcohol increase the potency of natural chemical messengers like GABA (gamma-aminobutyric acid). However, regardless of the way a chemical affects your brain chemistry, dependence occurs when your body starts to adapt to the drug’s presence in your system.
Dependence often starts with tolerance. As you continue to use a drug, it starts to have diminishing effects over time. To achieve the same effects you experienced when you first started, you’ll need to take more and more of the drug. This is because your brain might be counteracting the foreign chemical to balance brain chemistry. If you miss a dose or if you stop using, your brain chemistry will become unbalanced, and you’ll feel the effects of withdrawal. Some drugs are psychoactive, but your brain doesn’t adapt to them in a way that causes chemical dependence.
For instance, psychedelics like DMT are powerful hallucinogens that alter chemical messengers in the brain to produce psychoactive effects. DMT can cause tolerance if you take the drug in several successive doses. However, your brain doesn’t build a long-lasting tolerance to the drug and doesn’t adapt brain chemistry around it. Each time you use it on different occasions, it will have the same or similar potency. When you stop using it, you won’t go through a significant chemical withdrawal period. In some cases, drugs that don’t cause chemical dependence can cause psychological dependence. That is when a drug causes psychological symptoms of discomfort when you stop using.
Other drugs, like heroin, can significantly alter brain chemistry in a way that causes your brain and body to get used to it, causing uncomfortable withdrawal if you try to stop. Other common drugs that cause significant dependence are cocaine, meth, alcohol, sleeping pills, and other opioids. Chemical dependency isn’t permanent and can be reversed through detoxification. However, some substances like alcohol can cause potentially dangerous withdrawal and may need medical help to safely treat. For the most part, withdrawal symptoms subside after a week. Some symptoms, like psychological ones, can last long, especially without treatment.
Addiction is often a word used as a synonym for dependence, but it’s actually a distinct diagnosis. While dependence is a problem that affects the chemical messaging system in your brain, addiction effects some of the deeper parts of your brain, and it’s more difficult to overcome. According to the American Psychiatric Association, addiction is a brain disease that’s characterized by compulsive substance abuse even despite severe consequences. Addiction is officially diagnosed as severe substance use disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM–5). Addiction primarily affects the reward center of the brain, which is closely associated with the limbic system.
The reward center is a part of your brain that identifies and encourages healthy, life-sustaining activities. It does this by picking up on activities that cause a release of certain “feel-good chemicals” in the body like dopamine, endorphins, and serotonin. Once the reward center identifies an activity that’s good for you, it will encourage you to repeat those activities through compulsions and cravings. This helps you to continue to seek food, water, and other important things that help you survive, even if you’re tired or wouldn’t otherwise expend the effort.
Unfortunately, many psychoactive drugs also affect or cause a release of those feel-good chemicals, tricking your brain into mistaking something like heroin use for a life-sustaining activity. Drugs can also cause a chemical response that’s much more powerful than other natural activities. So you may start to seek drug use over other important things like food, personal hygiene, maintaining relationships, and performing at work.
For the most part, dependence can be reversed after a week of abstinence. It can be an extremely uncomfortable and even dangerous process, but dependence isn’t permanent. Addiction is more difficult to overcome. According to the National Institute on Drug Abuse, detox is an important part of addiction treatment, but it’s usually not enough to facilitate lasting freedom from addiction. Instead, addiction treatment should be longer-lasting, and it should address a range of areas in your life, including your health, social life, finances, and legal standing. Addiction often includes psychotherapies that are designed to address underlying issues, especially any mental health problems.
Though dependence and addiction are two separate things, they are closely related. Most people that present to addiction treatment have both problems simultaneously. When a substance use disorder develops into a chemical dependence, if it’s left untreated and unaddressed, it’s more likely to grow into an addiction. People that are caught in a pattern of active addiction to drugs like alcohol, heroin, or cocaine will also be chemically dependent on the drug. Uncomfortable withdrawal because of dependence and drug cravings from addiction often work together to feed into a person’s substance use problems. Both issues have to be addressed to facilitate recovery.
If you or someone you know is struggling with a substance use disorder, seeking help early can help prevent some of the most severe consequences of addiction. It may also prevent chemical dependence from growing into an addiction. Learn more about addiction and how it can be treated to take your first steps towards lasting recovery.
American Psychiatric Association. (n.d.). Diagnostic and Statistical Manual of Mental Disorders (DSM–5). Retrieved from https://www.psychiatry.org/psychiatrists/practice/dsm
Bellum, S. (2010, October 7). Word of the Day: Psychoactive Drugs. Retrieved from https://teens.drugabuse.gov/blog/post/word-day-psychoactive-drugs
National Institute on Drug Abuse. (2016, February). 8: Medical detoxification. Retrieved from https://www.drugabuse.gov/publications/teaching-packets/understanding-drug-abuse-addiction/section-iii/7-medical-detoxification
SAMHSA. (2019, April 13). Mental Health and Substance Use Disorders. Retrieved from https://www.samhsa.gov/find-help/disorders
U.S. National Library of Medicine. (2009, September 9). gamma-Aminobutyric acid. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/gamma-Aminobutyric-acid