Its a form of natural selection: Those stupid enough to get involved with drugs often end up dead. It actually improves the gene pool in that regard.
Not really that often.
With the estimated 2.7 million people who take recreational (illegal) drugs in the UK, there are ~2000 deaths due to it : 0.074%. Most of that is overdosing with Heroin, which in itself is a small % of the overall recreational drug use, and that is down to the fact there is no control over purity.
So really, mostly often people take their recreational drugs, have a good time, and continue with their productive lives normally
