It's not so much the drugs, its the way people use them. If someone is taking a bunch of asprin everyday, eventually, their stomach will fall apart and blood will start going everywhere in your body.
I realize some drugs are harder to get off once you are addicted, but that is a test of someone's will power. If they don't have the personal will power to quit a drug, then there should be help available. How would people afford that? Quit spending money on throwing some dude selling nickle sacks at the local concert downtown.
But, this isn't a legalization thread. Just realize that it's the person that choose to take the drug. I doubt they were held down and forced to take whatever drug it is. Sure, they might need help, but don't blame the drug. Blame them for taking it.
There are plenty of people that can take their drug of choice and still function. There are plenty that can't. People have to make that decision. Sometimes, if you are using particular drugs, you think you can handle things. But, obviously, many times they cannot. This is where intervention and rehab help. But, it's not the drugs fault. That would be like banning all video games because some people have seizures while playing them. There are plenty of people that don't have seizures. There are plenty of people that can take their drugs of choice and function fine. If you can't, then you need not take them. Find something else to stimulate yourself.