The five most addictive substances in the world have been revealed
Number four isn't one that you'd know off the top of your head either.
Asking the question, 'what are the most addictive substances in the world?' may seem simple in theory but in actuality, the answer depends on who you ask.
From the point of a researcher, an addictive substance can be judged on many things such as the harm it causes, the street value of the particular substance, how pleasurable it can be, the degree to which the substance causes withdrawal symptoms and how easily someone can become hooked on the substance.
A group of addiction experts, including specialists from the Royal College of Psychiatrists as well as chemists, forensic scientists and pharmacologists, took a stab at listing them by averaging numerous aspects of addiction.
The results were published in the journal The Lancet and here's what they concluded were the top five most addictive substances on the planet.
Alcohol interferes with messengers in the brain called 'excitatory' which slows down our thinking, breathing, and heart rate.
However, at the same time, it boosts our inhibitory messengers which gives us feelings of pleasure.
It was given a 1.9 out of 3 addiction rate.
You may not have come across this word before and you wouldn't be the only one. This substance (also known as downers) is sometimes prescribed for those with anxiety or insomnia, Xanax and Valium being two different types.
At low doses, it will induce a feeling of euphoria but a high dosage can suppress your breathing and actually kill you, giving it a rating of 2 out of 3.
When nicotine is sucked up by the lungs and delivered to the brain, its drug levels can peak within ten seconds of being inhaled.
Researchers believe that because the effects vanish so quickly, smokers are more prone to use the substance more frequently in order to get that hit again. It got a rating of 2.2 out of 3.
In seconds, cocaine fills the brain with the feel-good chemical, dopamine. The sensation has been found to be so pleasurable that some lab animals choose cocaine over food until they starve.
Cocaine appears to actively affect the brain's key memory centres which could be the reason why it's so addictive, giving it a rating of 2.4 out of 3.
The brain converts heroin into morphine which binds to molecules on cells that affect how we perceive pain and reward.
This produces a surging sense of euphoria but overdosing can kill as it slows and can stop breathing. It got a full 3 out of 3 score by the researchers.
They made it clear that because a substance is legal, doesn't make it any less harmful and addictive for you...
"Our results also emphasise that the exclusion of alcohol and tobacco from the Misuse of Drugs Act is, from a scientific perspective, arbitrary.
"We saw no clear distinction between socially acceptable and illicit substances. The fact that the two most widely used legal drugs lie in the upper half of the ranking of harm is surely important information that should be taken into account in public debate on illegal drug use."