Hallucinogens and psychedelics do not share a common mechanism of action, but all induce hallucinations .
All drugs in the opiate class act on opiate receptors in the brain. They mediate relief from pain and produce feelings of euphoria.
A substance capable of altering attention, memory, judgment, time sense, self-control, mood, or perception.
Sedatives and hypnotics depress or inhibit brain activity and produce drowsiness, sedation, or sleep; relieve anxiety; and lower inhibition.
A substance that increases activity in the body and nervous system.