Any form of addiction is harmful but drugs are the most addictive and it seems bizarre that some of the most addictive are legal and earn the Government money despite the knowledge that if taken in large or long enough doses, they will prove fatal.
A panel of experts have made up a list of the five most addictive substances based on the harm it causes, the value of the drug, the extent to which the drug activates the brain’s dopamine system, how pleasurable people report the drug to be, the degree to which the drug causes withdrawal symptoms, and how easily a person trying the drug will become hooked.
Heroin was ranked as the most addictive drug which causes the level of dopamine in the brain’s reward system to increase by up to 200%. The dose that can cause death is only five times greater than the dose required for a high.
Cocaine is second as it turns the dopamine signal off, resulting in an abnormal activation of the brain’s pathways and approximately 21% of people who try cocaine will become dependent on it.
The third most addictive, and legal, is nicotine and approximately 66% of people who tried smoking reported becoming dependent on it.
The World Health Organisation (WHO) estimate that diseases directly related to smoking kills more than 8m people annually.
Fourth, and another legal drug, is Barbiturates or downers which were used to treat anxiety and to induce sleep by interfering with the chemical signalling in the brain, effectively shutting down various brain regions and Barbiturate dependence was common when the drugs were easily available by prescription.
Fifth in the list is alcohol which increases dopamine levels by 40-360% – and the more alcohol which is consumed, the more dopamine levels increased.
Some 22% of people who drink will develop dependence on alcohol at some point during their life and the WHO has estimated that more than 3m people die annually due to damage to the body caused by drinking.