Psychedelic drugs have an ancient history of use, 4000 year old marijuana has been found in Chinese storage containers, the Aztec people used psilocybin mushrooms for religious purposes, peyote has a long tradition of ceremonial use, and the shamans of the amazon have used not only Ayahuasca (DMT) for a very long time, but also a myriad of drugs that very, very few westerners have seen, heard of, experienced, and definitely not experienced to the degree that these people did. These plants have long been the subject of study and curiosity, many academics have had a great degree of interest in them, and many psychologists have made their careers off of LSD. Drugs are SUCH an integral part of our society, but we usually choose a couple that are sanctioned, and vilify the rest for the sake of control (social, economic, and political).
It is naive to assume that
a) drugs are bad for you, and
b) drugs are recent cultural developments
how's that for a curveball?
(that said, everything in moderation.... you can get ulcers from mushrooms, and really lose yourself for a while from a bad trip. psychedelics are not toys which is why they're ceremonialized in most societies that used them effectively)