There's a strong gay subtext: drug dealer Ralph (Dave O'Brien) sees high schooler Jimmy (Warren McCollum), murmurs "Nice!", and practically licks his lips in anticipation.
Wrangling an introduction, he says "Nice to meet youuuuuu!" with a lascivious leer, then invites Jimmy to the soda shop, where he will try to get him hooked on the psychosis-inducing weed in a parallel to how gay men were accused of recruiting boys.
After Jimmy is tricked into taking a puff of "the evil weed," he is plagued by instant addiction, psychotic rambling, uncontrollable sexual desire (the most horrifying to audiences of the day ), drunk driving, and finally murder. It seems laughably sensationalistic today, but in fact Harry J. Anslinger, the commissioner of the Federal Bureau of Narcotics from 1930 to 1963, devoted his entire career to feeding the flames of the panic. As late as the 1950s, marijuana was considered more dangerous than heroin.
The movie was placed on the exploitation circuit, officially meant to educate viewers about the "dangers" of the practice, but really drawing crowds interested in gawking at the degradation. In the 1970s it was discovered by the hippie art-house crowd, who would watch while high for an ironic twist.
In addition to the gay subtext, there was a lot of beefcake, with the super-muscular Jimmy stripped down to his underwear and a chorus of semi-nude male and female devils.
Film beefcake, bulges, and frontals after the break