What Are the Most Addictive Drugs in the World?

Drugs on a gray background.

It’s no small task to measure the addiction potential of a substance. But researchers still put in the effort do this in order to furnish us with valuable information about different drugs. That information can help us greatly in addressing the drug crisis that our nation is mired in. 

Not all drugs are created equal. Some are far more addictive than others.

According to CNN Health, here are the main criteria that researchers use to determine the overall addictiveness of a drug:

  • How much harm does the drug cause?
  • What is the street value of the drug?
  • To what extent does the drug activate the brain’s dopamine system?
  • How pleasurable do users report the drug to be?
  • To what degree does the drug cause withdrawal symptoms?
  • How likely or unlikely is it to get hooked on the drug?
  • How easy or difficult is it to get off of the drug?

Researchers compare the survey results from active drug users which then assists those who study addiction in arriving at relatively sound theories about the overall addictiveness of various substances.

Here is an example of how this analysis works in action. Comparing heroin and marijuana, research has shown us that, for the most part, heroin is more addictive than marijuana. Heroin has a higher street value. It actives the brain’s dopamine system on an entirely higher plane than marijuana does. It is conceived to produce a more powerful effect on the user. It can cause addiction after just one use. It creates far more painful withdrawal symptoms and is harder to get off than marijuana.

In using the above conclusions, we can see that heroin is a more addictive, more dangerous, and overall more harmful drug than marijuana.

The Top Five Most Addictive Drugs in the World

The academic, peer-reviewed paper “The Development of a Rational Scale to Assess the Harm of Drugs of Potential Misuse” puts forth not only the metrics for measuring a drug’s relative addictiveness but also the researchers’ viewpoints on which are the “top five most addictive drugs.” The full research paper can be viewed with free registration at The Lancet. (A summarized version of the research can also be viewed at CNN Health, mentioned and linked above).

The five most addictive drugs based on the research data are as follows:

Brown heroin in powder form.

1. Heroin. Heroin earns first place, as it is an opiate that causes dopamine in the brain to increase by 200%, creating powerful, lasting, habit-forming highs. Heroin is not only extremely addictive, but it is dangerous. Just five times the dose needed to get high is lethal, and it’s not hard to make a mistake when measuring out a dose.

Cocaine drug.

2. Cocaine. Cocaine comes in close second, being a drug which can alter dopamine levels by a whopping 300%. The cocaine market is worth $75 billion dollars, and 14 million to 20 million people use cocaine worldwide. Cocaine would likely be number one on the list, were it not for the fact that cocaine does not cause nearly as many deaths as heroin does.

Vape and cigarettes.

3. Nicotine. Nicotine, the main ingredient in tobacco, is one of the most addictive drugs in the world. More than two-thirds of Americans who try smoking tobacco cigarettes will become dependent on cigarettes at some point in their life. Every year, tobacco kills about 8 million people worldwide. The nicotine in tobacco increases dopamine levels in the brain by about 25% to 40%.

Bedside pills—Barbiturates.

4. Barbiturates. Barbiturates are highly addictive, but they are not all that easy to get, so they do little harm on the grander scale of drug use. Though barbiturates are addictive, fewer people use them than heroin, cocaine, and nicotine. However, when individuals do use this drug, a low dose of barbiturates causes euphoria, and higher doses can suppress breathing and even cause death.

Alcohol bar shelf.

5. Alcohol. Some researchers argue that alcohol is the most addictive drug in the world simply because of how many people drink to excess. But for the sake of this discussion, we’ll keep the ranking of fifth place that the researchers
gave it. 

Alcohol is said to boost the brain’s reward system by 40% to 360%, depending on the person who is consuming it. More than one-fifth of those who try alcohol will develop a dependency to it at some point, and at least 3 million people across the world die from alcohol misuse every year.

The Relative Addictiveness of Drugs Might Be Relative, But No Type of Drug Use Is Okay

When applying the data to an individual, however, a different way of looking at addiction is needed.

When all of the cards are on the table, there is a significant degree of relativeness when it comes to addiction factors with various drugs. For John, heroin might be his drug of choice, and for him, heroin is the most addictive drug in the world. 

But for Jack who smokes marijuana on a daily basis and who has been doing so for a decade, life without marijuana might seem completely impossible to him. One could say that John and Jack are more or less equally addicted to drugs which, to them, are incredibly addictive.

So there is some relativity here. However, while Jack uses marijuana, he won’t likely die from a drug overdose, he won’t likely experience terrible drug withdrawals, he won’t likely form a chemical dependence, and so on. All of this could and likely will happen to John, the heroin user, which is why heroin is considered the more addictive of the two drugs.

Let’s Address All Drug Addictions with Equal Parts Compassion and Dedication

The main point in the above section is that both John and Jack need to get help for their drug habits, regardless of one habit being with heroin and the other being with marijuana. At the end of the day, it doesn’t matter what kind of addiction one has. Addiction is addiction. All are harmful, all present danger, and all require treatment and rehabilitation help for individuals to break free from them.

And that’s what it really comes down to. It’s good to know which drugs are the most addictive. We can protect our kids, homes, and communities better with this information. We have a better idea which drug problems should garner a priority to address when we know more about them. But the truth is, no matter what the drug of choice is, all addicts need help for their drug habits.

“... because so many people use marijuana, cannabis dependence is twice as prevalent as dependence on any other illicit psychoactive substance.…”

According to the article “Marijuana Dependence and Its Treatment,” a research paper published in the U.S. National Library of Medicine, which proves the addictive factors of marijuana: “Marijuana produces dependence less readily than most other illicit drugs. Some 9 percent of those who try marijuana develop dependence compared to, for example, 15 percent of people who try cocaine and 24 percent of those who try heroin. However, because so many people use marijuana, cannabis dependence is twice as prevalent as dependence on any other illicit psychoactive substance (cocaine, 1.8% heroin, 0.7%).”

Even though heroin and cocaine are far more addictive than marijuana, there are more marijuana addicts than heroin addicts or cocaine addicts. 

Let’s use the information on the relative addictiveness of drugs to further our understanding of these terrible substances, but let’s make our focus be on addressing all addiction in America, and let’s focus on helping every addict overcome their habits so that they might live a happy and peaceful life that is free from the harmful effects of mind-altering substances.


Reviewed by Claire Pinelli, ICAADC, CCS, LADC, RAS, MCAP



After working in addiction treatment for several years, Ren now travels the country, studying drug trends and writing about addiction in our society. Ren is focused on using his skill as an author and counselor to promote recovery and effective solutions to the drug crisis. Connect with Ren on LinkedIn.