And here’s what they do to your brain.
Which drug is the most addictive? Depending on who you ask, you’ll likely get different answers.
According to various researchers, there are a number of different ways to judge the addictiveness of a drug — how much the drug activates the brain’s dopamine system, how much harm it causes, the drug’s street value, what kind of withdrawal symptoms come with the drug, how pleasurable users report it to be, and how easily someone who tries the drug will become hooked.
David Nutt, a psychiatrist and neuropsychopharmacologist who specializes in drugs research, and his co-researchers put together a ranking system for addictive substances, comprising a list of the five most addictive substances on Earth:
Unsurprisingly, heroin took the number one spot. The experts ranked it as the most addictive drug on the planet, scoring a 2.5 out of the maximum score of 3 in the rankings.
Research has shown that the opiate causes the level of dopamine in the brain’s reward system to skyrocket up to 200 percent in experimental animals. Not only is heroin extremely addictive, it’s dangerous — the dose that can cause death is a mere five times greater than the dose needed for a high, as The Conversation’s Eric Bowman reports.
Heroin use has more than doubled among young adults ages 18 to 25 in the past decade, according to a recent report by the Centers for Disease Control and Prevention (CDC).
Since alcohol is a more widely accepted (and legal) means of intoxication, many may overlook the true addictiveness of it as a drug. Alcohol earned a score of 2.2 out of the maximum 3 on the experts’ scale due to its various effects on the brain.
In a laboratory study with rats, researchers found that alcohol increases dopamine levels in the brain’s reward system by anywhere from 40 to 360 percent — the more the animals drank, the more the dopamine levels increased.
Other studies have found that about 22 percent of people who have drunk alcohol will go on to develop a dependence at some point in their life.
Cocaine came in third place on the list since the drug essentially prevents neurons from turning off the dopamine signal, which leads to an abnormal activation of the brain’s reward pathways. Shockingly, animal experiments have shown that cocaine causes dopamine levels to rise more than three times the normal level.
Not only is cocaine highly addictive, but a recent study found that a cocaine-affected brain actually causes brain cells to commit suicide by eating themselves — doesn’t sound too pleasant.
Plus, about 21 percent of people who try cocaine will become dependent on the drug at some point in their lives, according to the results of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC).
4. Barbiturates (“Downers”)
Barbiturates are a class of drugs that were initially used to treat anxiety and help people with sleep problems, however they’ve been widely replaced by a new class of drugs, benzodiazepines, including Xanax and Valium.
Also known as pink ladies, blue bullets, gorillas, and barbs, the drugs earned their fourth place spot because of their easy availability as a prescription drug. However, on a positive note, this availability has recently declined due to the rise in popularity of benzodiazepines.
Barbiturates interfere with chemical signalling in the brain, which shuts down various brain regions. The drugs cause euphoria at low doses, but at high doses, they can be lethal since they suppress breathing.
According to the CDC, an estimated 40 million adults in the United States alone smoke cigarettes, so it’s no surprise that nicotine made it on the list of the most addictive substances in the world.
The NESARC results reveal that over two-thirds of people who try smoking will go on to become dependent on cigarettes during their lives. A study with rats found that the animals can learn to press a button to receive nicotine directly in their bloodstream, which raises dopamine levels in the brain’s reward system by about 25 to 40 percent — not as high as heroin or alcohol, but still significant.
Curious how addiction actually transforms the brain? Read about it here.
h/t: The Conversation