There are many good reasons not to take drugs. Other than addiction and the possibility of overdose, the next best reason is that, Walter White notwithstanding, neighborhood chemists aren't terribly trustworthy.
Fentanyl
The overdose epidemic sweeping the nation is hitting some demographics harder than others. New data released by the CDC breaks down heroin overdose deaths by age.
On March 4th, 2016, I testified at FDA about the opioid addiction crisis in the U.S.
In 1985, a scientist in Delaware decided to make drugs with the goal of getting rich.