One of the most potent of the hallucinogens, with an effect of over 12 hours and flashbacks which can occur within a few days or more than a year later is called:

A. MOMA Possibly a typo for MDMA (ecstasy), which is a stimulant with some hallucinogenic properties, but not as potent or long-acting as LSD. Flashbacks are less common with MDMA. B. LSD LSD (lysergic acid diethylamide) is a powerful hallucinogen. It causes long-lasting trips (8–12+ hours) and can produce flashbacks (hallucinogen persisting perception disorder) long after use. C. SSRI SSRIs are antidepressants, not hallucinogens. They do not cause euphoria or flashbacks. D. PCP PCP is a dissociative drug, not a classic hallucinogen like LSD. Effects are usually shorter in duration, and flashbacks are less typical.