what do we judge that a substance is addictive? According to the researchers, this particular calculates according to the damage it causes, the ease with which the person is going to become addicted and how it activates the brain’s dopamine system. But there are other ways to measure the addictive potential of a drug, which depend on researchers. One way to classify them is to ask a group of experts. This is what makes David Nutt and his colleagues in 2007 with experts in addiction, says Eric Bowman, Lecturer in psychology and neuroscience at the University of St Andrews, in an article written for The Conversation.

1. Heroin

The heroine finds himself in first position, with an addictive score of 2.5 on a maximum of 3. Heroin is an opiate that causes an increase of 200 % of the level of dopamine in the brain, according to the experiments on animals. In addition to being the most addictive, heroin is also dangerous because the lethal dose is only five times the dose required to be “high”. She also ranked second most harmful drugs to consumers and to society.

2. Alcohol

Although legal in many countries, alcohol obtained the second position with a score of 2.2 to 3. The alcohol produced many effects on the brain, including the right to increase between 40% and 360% the level of dopamine in the brain’s reward system. The more one drinks, the more the level of dopamine increases. About 22% of people who tasted the alcohol will become addicted at some point in their lives. Alcohol was also ranked as the most harmful drug of all in the long term, according to other experts.

3. Cocaine

cocaine prevents neurons to switch off the signal of dopamine, which leads to abnormal activation of the brain’s reward pathway. In animal experiments, cocaine caused a three-fold increase in dopamine levels relative to normal. About 21% of people who have tried cocaine become addicted someday. It is similar to other addictive stimulants, like methamphetamine and amphetamines.

4. Barbiturates

barbiturates were originally used to treat anxiety and sleep disorders. They interfere with the chemical signaling in the brain and cause the closure of various brain regions. At low doses, barbiturates induce euphoria, but in high doses, they can be deadly because they put breathing difficulties.

5. Nicotine

Nicotine is the main addictive ingredient in tobacco. When someone smokes a cigarette, nicotine is quickly absorbed through the lungs and delivered to the brain. Moreover, it is incredibly addictive. More than two-thirds of Americans who smoked were dependent for a shorter or longer period of their lives.