Drug addiction and treatment substance abuse happens quite legally. Prescription medicines are very addictive drugs. I have put together some interesting videos for your perusal.
Oxycodone is a strong opioid analgesic (pain killer) drug with a high potential to cause physical and psychological dependence. Once the addictive problems of heroin and morphine became well known, it was decided not to make pain killers using morphine substitutes.
Source: Addictionsearch.com
OxyCodone Addiction: This video does contain strong language.
Xanax and Niravam, is a short-acting drug of the benzodiazepine class used to treat moderate to severe anxiety disorders, panic attacks, and as an adjunctive treatment for anxiety associated with major depression.
Source: Wikipedia
Xanax (anxiolytic addiction and withdrawal)
