For New Agers, Hindus,?

Lately I've been exploring the realm of entheogens and mind altering plants. As you know, these substances have been used for thousands upon thousands of years by humans all over the world for religious and recreational purposes. My opinions are conflicting, as I draw from eastern and western spirituality. My question is this... Do you think these substances are helpful, or baneful to the psyche or spirit? I have heard many, many contradicting sources. Some say these plants and substances can damage the subtle, underlying, and highly impressionable energies of the spirit, while others say they can cause revelations and great insights, while raising creativity and bring a feeling of closeness to nature. Some say that in moderation, along with practices like yoga, meditation, study, etc., these substances can be helpful. I have experimented with Cannabis Sativa, and find it to be a very pleasurable, creative, and opening experience, and believe that psychedelics used should be natural, not chemical. What are your thoughts on LSD, Mescaline, Cannabis, LSD, etc.?