Drugs are no matter of joke in today's world. Each day more and more people get addicted either due to peer-pressure, depression, curiosity or just pure fun. But no reason is big enough to get indulged into something that may result in your death.
Addiction is a disease that effects both brain and behaviors. It can cause all sorts of side-effects such as tiredness, bad-grades, hallucinations etc. Excess drug abuse may lead to death as well.