There is a long history of relations between different types of arts and drugs.
Even those Sumerians from 5 thousand years ago that wrote all those tablets in cuneiform praised the opium as their "joy". We have the first mention of alcohol in 3500 BC from Egypt. Those guys who were writing those informations on papyrus, were the artists of that age and they spoke pretty nice about heavy drinking. You can find many lines in Bible encouraging people to drink wine. They had already developed culture of opium in China in 1000 AD, tobacco comes to the Europe with Columbus in 1493, we have traces of hashish in Shakespeare's pipe along with many other proves and findings about artists taking "drugs for inspiration". There are also many historical documents about prohibitions of alcohol, drugs and tobacco in United Kingdom, Russian Empire, Ottoman Empire, United States... All this leads to the fact that the most of us come from a long line of heavy drinkers and drug abusers.
And then we came in 1920's, when the relation between drugs and arts becomes much stronger.
Especially with musicians.
Now is the time to separate drugs, alcohol and tobacco and in the next lines, I'll speak only about the drugs.
Jazz players smoked weed in 1920's. I don't consider marijuana as a drug, since I have never heard that someone came home "high" and beaten his wife and kids or caused a traffic accident, so when you type in google something about "musicians and drug abuse", the most of results are about weed. I would just let Snoop Dogg smoke as much as he can and it is not big deal.
Did you know that Louis Armstrong was arrested because of marijuana possession in 1931?
The real drug problem with the musicians came in 1960's when the whole scene of new and old drugs started flowering. Psychedelic era... New substances created new sounds. It's true because under the influence of drugs, musicians started to improve the sounds they had before and they made many new "drug influenced" genres that we have today. Fans of the famous bands and singers developed the whole cultures around drugs and music, the peak were late 60's with LSD.
I think it's not necessary to list down all names of addicted musicians and drugs, I would probably miss to list someone important, but we all know those names. In last 60 years we heard a lot of bad news, didn't we? So from David Bowie, Bob Dylan, Ray Charles, Brian Jones, Kurt Cobain... to Britney Spears, Amy Winehouse, Whitney Houston...
You gotta admit, those people I listed had the greatest music!
So what's the point, why they were taking it?
There are more than few reasons why some musicians start taking drugs.
- Inspiration - Many songwriters and composers claim that drugs open the inspiration to them. This is not proved by science, but also it isn't proved that those claims were false.
- Pressure - It's not easy to deal with fame. It is maybe easier with drugs.
- Fans - You can't drink orange juice and play your music in front of bunch of drugged and drunk people in front of the stage.
- Way of life - Well, musicians don't get up at 8 AM after gig to make some pushups. If they are young, they want try all. And it is easier to convince the younger person to... anything.
- Money - The most of these guys were born poor. They made their way outta misery and now they want to live the life!
Disclaimer
Don't do drugs! It won't make you famous! You're not so lucky! :)