Some people do not take drugs to avoid reality. They take them to explore it. What one has to realize is that the experience we call "reality" is only a subjective image created by our minds. There is a chain of filters applied to everythings our sensors (eyes, ears, skin and so on) register. Drugs are able to influence those filters. Hence one might be able to see "reality" from a different point of view.

(Disclaimer: I've never taken any drugs besides light alcohol and caffeine use and some medical stuff, but that doesn't mean I can't spot the obvious contradiction here.)