The doses are acute so the side effects at reasonable doses are primary psychotomimetic effects without physical harm or other behavioral impact - it has a very short half-life and people will be basically sober by the time they leave from a treatment and the body will clear it in a day. The effects last beyond that because they cause a systemic brain change and psychological effect, not because there is a drug present.

social cost = effects on family, close friends and relatives, and occasionally society in general.