Drugs and alcohol can open up a spiritual experience. But, as Bhagavan Das pointed out, it’s a dark (tamasic) path and the danger is in being eaten up or swallowed by the substance, instead of the other way around.
I haven’t taken hallucinogens. (I’d like to, someday, with reformed drug addict Rudy as a “guide.” To make sure I don’t harm myself or another…)
I think my first experience of “psychedelia” was Sesame Street. (“1,2,3,4,5…6,7,8,9,10…11,12… doodoodoodoo…,” among others…) My parents were not hippies. They listened to Bread, middle-of-the-road stuff…
But I had a cool uncle and aunt. My Uncle Boyet brought me to an open-field rock concert when I was maybe 6… where I think I first heard Pepe Smith. This uncle would show me his psychedelic paintings and taught me my first cool words: “Hayuup!” “Haneeeep!”