I'm more curious why psychedelics are (or were) viewed as something that can cause social problems. It's more clear with drugs that create physical dependence, like opioids or dopamine reuptake inhibitors (cocaine, amphetamines). However, drugs in those classes, along with other addictive drugs like benzodiazepines, are legal with a doctor's prescription.
Why can't people take LSD once a year in a safe, supervised setting?
``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...
I don't have a good answer, but I do know that LSD came around when there was a lot of change going on in the world. That might have had something to do with it.
I'm actually pretty curious now, so I'll look into it.
Why can't people take LSD once a year in a safe, supervised setting?