The history of LSD is one of great potential gone lost. The early research in mental health and creativity was highly promising. Stan Grof was one of the leading experts on LSD in psychology before the drug was banned. His research has had a lasting impact on how some psychologists understand pre- and perinatal psychology, not to mention his work in transpersonal psychology.
The military thought the drug was useful as well. Unfortunately, the CIA and the military dosed subjects without their knowledge -- many died.
When the drug made its way into mass culture and threatened to generate serious cultural upheaval, the drug was made illegal and designated a Schedule I narcotic -- which is a faulty designation. This kept it out of researchers hands, however, and effectively ended any potential it might have in mental health.
I personally credit LSD and psilocybin for much of my awakening in my late teens and early twenties. It didn't suddenly make me awake (aside from the drug-induced experience), but it showed me there was more to my mind than I ever could have known, and it revealed, for me, an interconnectedness in all things that motivated me to find that same connection without the drugs.
As the video points out, most of the scare stories about the drug were false or overblown. Yeah, some people didn't react well, but that just highlights the need for more research in controlled environments. All of the hallucinogens have the potential to teach us a great deal about how our brains work and perceive the world, and the research should never have been stopped.
OK, didn't know I was going to rant. Here's the video.