There are many substances we become dependent easily. Some of them are legally prohibited. Each substance differs from each other in its characteristics and the level of harm to body and mind.
Independent: The 5 most addictive substances on the planet
According to the article above, the worst addictive substances are heroin, cocaine, nicotine, barbiturates, and alcohol.
This list makes sense, in my clinical experience, although I have never met patients with heroin dependence. Previously, Japanese psychiatrists frequently prescribed barbiturates as a narcoleptics. It is quite rational that they were replaced with benzodiazepines since their development. Nonetheless, I sometimes see patients using barbiturates even recently.
I remember that alcohol showed stronger dependence than nicotine in an experiment with monkeys. In this experiment, monkeys were encouraged to press a button to take more alcohol. But finally, they were completely drunken, to be disabled to continue the experiment.
This article is based on a study published in 2007. In the original article, several factors were considered to calculate the dependency. As well, the levels of physical and social harm are evaluated. About social cost, the top of the list is heroin, followed by alcohol.