Answer:
Drugs mostly harm today's society. They cause permanent physical, emotional, and mental damage, and very few can recover. Drugs often lead to sickness and disease. Overall, the consequences are widespread. Not to mention, the cost of drugs is a big issue and it becomes even bigger when one considers how the user's addiction causes them to buy even more. The addiction makes people more violent, as well as more inclined to persuade others to take part in these drugs.
The use of these drugs affects people's comprehension and common sense, giving a rapid increase in car crashes, injuries, and arrests. Especially in this modern society, people have more ways to pass on drugs (by texting others, threatening to "expose" others online, and viewing more TV ads for drugs.)
I don't know if this is quite 500 words, but at least it is a start. Hope it helps!