Sure, some claim to have used drugs to reach a higher plane of awareness or oneness with the universe, and I can see how that might be possible. However, all too often those same people have come to depend on the drug(s) of choice to maintain some other sort of equilibrium that appears from this vantage point to be a hindrance.
Maybe for some, but not for me.
Psilocybin mushrooms are a fantastic way to induce a full-blown spiritual awakening in its user (given the right mindset and environment) and it is by far my favourite drug. And yet, I do mushroom trips every six months or so. Anyone who has used a psychedelic drug like this one (or LSD or mescaline, but particularly 'shrooms) will tell you that the 'oneness' feeling that you have with the univers under the influence is something that is faaaar beyond mind-blowing - it truly is mind-expanding. You just don't see things the same way after an experience like this, it completely realigns your perspective and your priorities in life. It's very hard to explain to someone who has never taken 'shrooms, but I believe it's something that everyone should experience at least once in their lifetime.
The fact that this drug is outlawed by governments almost everywhere on Earth is a very good example of how The Man(tm) desperately wants to keep us down and in line, like sheeps. Psychedelics awakens you from the default slumber that the powers that be impose on us from an early age. Once you embark on that journey, there is no turning back.
I'm just glad I awoke like more and more people everyday.