There is an adjectival oxymoron in the second paragraph: "clinical, nurturing environment". Clinical and nurturing are mutually exclusive, which is why many studies into hallucinogens and entheogens (as well as telepathy, telekinesis and other such parapsychological phenomena) failed to produce positive results. Many amazing therapies have been missed for the want of a less reductionist theoretical and experimental paradigm. As an occasional user of LSD, I cringe at what the Toronto test subjects must have experienced. Though he was a pop icon, many people forget that Timothy Leary was also a Doctor of Psychology at Harvard. He insisted that the crucial determinats of the nature and quality of an LSD experience are mindset and envronment, or what he called "set" and "setting". Clinical environments are not conducive to positive experiences on LSD. Safe, nurturing environments are.