``In a second procedure, which is the favored treatment in the United States, a single, very high LSD dose (0.3 to 0.6 mg) is administered after correspondingly intensive psychological preparation of the patients. This method, described as psychedelic therapy, attempts to induce a mystical-religious experience through the shock effects of LSD. This experience can then serve as a starting point for a restructuring and curing of the patient's personality in the accompanying psychotherapeutic treatment. The term psychedelic, which can be translated as "mind-manifesting" or "mind-expanding," was introduced by Humphry Osmond, a pioneer of LSD research in the United States.''[1]
Read the rest of the reference, you'll find why/how LSD became associated with the counter-culture, and then became illegal because of that. My take is that LSD, when administered responsibly, can lead to major positive life changes for those in need.
It is a pity that it is illegal, which only increases the risk of abuse/work dosage/mixing with other stuff, but perhaps in a more civilized age...
[1] Hofmann, Albert; LSD: My Problem Child; url ->http://www.psychedelic-library.org/child4.htm