One picture that is worth a thousand words. The vertical axis shows how addictive the drug is, the horizontal axis – how dangerous it is.
Data source: Gable, R. S. (2006). Acute toxicity of drugs versus regulatory status. In J. M. Fish (Ed.),Drugs and Society: U.S. Public Policy, pp.149-162, Lanham, MD: Rowman & Littlefield Publishers. Also published at Professor Gable’s page.