Abstract Of the 14 known types of serotonin receptors one of the most extensively studied is the 5‐HT 2A (5‐hydroxytryptamine) receptor. In the brain, this receptor plays a key role in regulation of cortical function and cognition, appears to be the principal target for the hallucinogenic/psychedelic drugs such as lysergic acid diethylamide (LSD), and also is a target for the newest atypical...