What Are the Most Addictive and Most Abused Drugs?

Medically Reviewed

There are hundreds of psychoactive substances people use every day for a variety of reasons. But not all of them cause substance use disorders and addiction. Drugs all work in the brain in unique ways. For instance, psychedelic drugs can have powerful effects on the human brain, causing intense hallucinations, altering your perception, and changing your level of consciousness. In some cases, they can have euphoric or even disturbing effects. But they don’t usually result in addiction. However, other drugs, such as opioids and stimulants, can be powerfully addictive.

Learn more about the most addictive drugs in the world and what makes them so hard to quit.

What Is Addiction?

Before you can understand the most addictive drugs, it’s important to understand what addiction actually means. It’s often used as an overarching term for everything in the realm of substance use disorder, or SUD. But it’s actually a distinct disease. Addiction is classified as a severe substance use disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). This sets it apart from drug abuse and chemical dependence, though it’s closely related to those issues and mild-to-moderate SUDs often lead to addiction.

Addiction is typically identified by the compulsive use of a drug. It’s no longer used for medical purposes. It’s not even for recreation. Instead, it’s a deeply rooted craving that can get out of control. If you’ve become addicted, you may continue using even after the drug causes serious consequences like health concerns, problems at work, or legal troubles.

When a substance use disorder becomes an addiction, it can be difficult to overcome without help. But even the most addictive drugs can be overcome with the right treatment. There is no known cure for addiction, but the right therapies and professionals can help you achieve long-lasting sobriety.

The Most Addictive Drugs

Addiction primarily affects the reward center of the brain, which is associated with the limbic system. The reward center’s job is to take notice of good, healthy activities and stimuli that you encounter on a daily basis, and encourage you to do them again. If you’ve ever said, “I like cookies,” it’s because your reward center noticed the positive effects cookies had on you in the past, and it’s letting you know, “that was a good thing, let’s do it again.”

This function is incredibly important for survival. It allows you to instinctively know that things that make you feel good like comfortable places to sleep, hearty meals, and good company can help you survive. Your reward center knows this because your brain releases “feel-good chemicals” like dopamine, serotonin, oxytocin, and endorphins when you encounter one of these positive stimuli.

The most addictive drugs in the world are usually ones that involve these chemicals. When you take one of these drugs, it causes one or more of these chemicals to surge. Your reward center can’t help but take notice in a significant way. When the powerful effects of drugs trick your reward center into believing using that drug is a healthy activity that should be repeated, you become addicted.

Here are some of the most addictive drugs that are commonly used in the United States and around the world:


Heroin, and opioids in general, have a notoriously high addiction liability. While most addictive drugs affect or alter your naturally occurring feel-good chemicals, opioids are feel-good chemicals in and of themselves. When you get hurt or exert yourself, your brain releases endorphins to regulate pain and help you recover. Similar chemicals are found all over nature as painkillers and defense mechanisms. One such natural source is the opium poppy, where we get morphine. In fact, we knew about morphine before we even discovered endorphins in the human brain. That’s why endorphins get their name from a combination of the words endogenous and morphine.

Heroin is a more powerful version of morphine that’s been altered with other chemicals. While it’s similar to your natural endorphins, it’s much more potent. So the effect it has on your reward center can cause deep, compulsive drug-seeking behavior.

Heroin is not only incredibly addictive, but it’s also overwhelmingly abundant. In fact, it’s one of the most easily accessible illicit drugs, second only to marijuana. In 2016, 948,000 Americans reported using the drug in 2016, and that number has been growing since 2007. Heroin is one of the main culprits in the opioid crisis, and it was involved in 15,958 overdose deaths in 2017.


Cocaine is a stimulant. While heroin slows you down and relaxes you, cocaine makes you feel excited, powerful, and energized. It works in the brain as a dopamine reuptake inhibitor. In other words, it blocks a process called reuptake, which removes and recycles excessive amounts of a chemical from the synapse. When you use cocaine, dopamine builds up in your brain and binds to more receptors, the result is an intense energized euphoria and sometimes anxiety, paranoia, or panic.

Dopamine is one of the main feel-good chemicals that’s tied to mood. It has a wide variety of functions, but one of its main roles is to regulate your mood and motivation. Cocaine causes your mood to lift and makes you feel empowered to accomplish anything, which proves to be incredibly compelling to your reward center.

Cocaine use reached epidemic levels in the 1980s and 1990s, but it has since stabilized, with no significant growth since 2009. Still, there were about 1.5 million cocaine users in 2014. Plus, while cocaine use hasn’t risen significantly, overdoses involving cocaine have gone up. However, this may be due to instances where cocaine is mixed with powerful opioids like fentanyl.


Meth is another powerful stimulant drug that works in a way that’s similar to cocaine with one major difference. While it blocks dopamine-reuptake like cocaine, it also increases the production of dopamine, flooding your receptors with the chemical. In fact, your dopamine receptors can become so overloaded that they sustain damage in the process. Because people who have used meth for enough time have fewer working dopamine receptors, they often experience from anhedonia, or the inability to feel pleasure, without meth. This perpetuates meth use because withdrawal can lead to deep depression and thoughts of suicide.


Alcohol is one of the most ubiquitous recreational psychoactive substances in the world. In the United States, as many as 86 percent of people have drunk alcohol at some point during their lifetime. In 2015, 27 percent of adult Americans reported binge drinking in the previous month. Drinking, and even binge drinking, is such a big part of our culture that people don’t realize it can be a powerfully addictive substance. Not everyone who drinks develops alcoholism, but 15.1 million American adults met the qualifications for an alcohol use disorder in 2015.

Alcohol is GABAergic, which means that it affects a chemical in your brain called gamma-Aminobutyric acid (GABA). GABA receptors are responsible for regulating excitability in the nervous system. In excess, GABAergic depressants like alcohol can cause chemical dependence and addiction. Other depressants that are used for medicinal purposes like barbiturates and benzodiazepines can also be incredibly addictive.


Next to alcohol, nicotine is among the most common recreational substances in the United States. Its legal status makes it easy to get, but it also makes it easy to study. Because of that, research has found that the consequences of using nicotine (especially when smoking cigarettes) can be serious. Smoking damages your lungs and leads to certain types of cancer, but people still can’t seem to quit. That’s because the drug is incredibly addictive. So much so that some researchers believe it might be more addictive than cocaine.

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