The addictiveness of a drug is judged by researchers from the extent to which the drug activates the brain’s dopamine system.
According to Dr Eric Bowman, researchers judge a drug's potential "in terms of the harm it causes, the street 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."
Here is a list of five most addictive substances on Earth and their effect on your brain:-
Heroin causes the level of dopamine in the brain’s reward system to increase by up to 200%. It is highly addictive and dangerous because an overdose can kill a person.
Alcohol increases dopamine levels in the brain’s reward system by 40-360%. It too has been ranked as the most damaging drug by experts.
Crack cocaine has been ranked by experts as being the 3rd most damaging drug. It directly affects the brain’s use of dopamine to convey messages from one neuron to another.
4. Barbiturates (‘downers’)
Barbiturates aka the blue bullets, gorillas, nembies, barbs or pink ladies is the 4th most addictive substance that shut down various regions of the brain.
Nicotine commonly found in tobacco is rapidly absorbed by the lungs and delivered to the brain thus making it amongst the most powerful addictive drug.