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The Most Addictive Substances In the World

There are many ways to judge the addictive nature of a substance. Different scientists say different things about the issue, but one thing is for sure. The main addictiveness comes from the drug that activates the brain’s dopamine system the most. Some other aspects to be considered when deciding on a substance’s addictiveness are:

  • How much harm it causes.
  • The type of the withdrawal symptoms that the drug triggers.
  • How pleasurable it is.
  • How easily you become hooked.
  • The drug’s street value.

According to a psychiatrist and neuropsychopharmacologist David Nutt, this is the list of the five most addictive substances on Earth:


Heroin is ranked as the most addictive substance on the planet! It scored 2.5 out of the maximum of 3 in the rankings. This drug causes the level of dopamine in the brain’s system to increase by up to 200 percent just in experimental animals. Apart from being extremely addictive, it is also extremely dangerous! The line between death and complete enjoyment is in the dose. The amount that can cause death is about five times greater than the one which causes the enjoyment.

In the past decade, heroin use more than doubled among young adults aged 18 to 25. 


We are well familiar with the fact that alcohol is a widely accepted means of intoxication. Being legal in almost all the countries in the world (except in 15 countries) the true addictiveness of it as a drug is somehow ignored. Alcohol got a score of 2.2 on the scale due to its effects on the brain (the maximum on the scale was 3). One laboratory study with rats showed that alcohol increases dopamine levels in the brain’s reward system from 40 to 360 percent. It was obvious that the more the animals drank, the more the dopamine levels increased. On the other hand, some other studies have shown that about 22 percent of people who have drunk alcohol developed a dependence at some time in life.


As we can see here, cocaine is in the third position on this list. It basically prevents neurons from turning off the dopamine signal, leading to an abnormal activation of the brain’s reward pathways. The experiments conducted on animals have shown that cocaine causes dopamine levels to rise more than three times the normal level. To show how dangerous it actually is. Some recent studies have pointed out that a cocaine-affected brain causes brain cells to commit suicide by eating themselves. Can you imagine that? It sounds so terrible just to think about it.

As the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) have suggested, about 21 percent of people who try cocaine become dependent on the drug at some time in their lives. Would you dare even try it?


Barbiturates were mostly used to treat anxiety and help people with sleeping disorders. In the previous century, benzodiazepines widely replaced them. Even so, they are easy to get as prescription drugs. Why are they so hazardous? Well, because of their interference with chemical signaling in the brain, which shuts down various brain areas. They cause euphoria at low doses, but when the dose is high, they suppress breathing. As such, they can kill almost immediately. Have you ever heard about people who killed themselves using these drugs? There is a huge number of such people. Marilyn Monroe is just one of them to be mentioned here.


About 40 million adults in the United States only are cigarette smokers! What a number! According to the Centers for Disease Control and Prevention (CDC), cigarette smoking is the leading cause of preventable disease and death in the United States. Over two-thirds of people who try smoking become dependent on cigarettes during their lifetime. Another study was conducted on rats. In the study, the animals learned how to put nicotine directly in their bloodstream by pressing a button. This raised dopamine levels in the brain’s reward system from 25 to 40 percent.


When a pregnant woman is addicted to some of these substances, the addiction can easily be, and usually is, transferred to a newborn baby. Do you know what happens when a baby is born while addicted to drugs? Read here

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