Which of the following substances is NOT a hallucinogen?

Amphetamines are classified as stimulants, not hallucinogens. They primarily increase energy, focus, and alertness by increasing the levels of certain neurotransmitters in the brain, particularly dopamine and norepinephrine. This leads to heightened mood and increased concentration, rather than the perceptual and cognitive distortions typically associated with hallucinogens.

In contrast, peyote and mushrooms both contain psychoactive compounds that lead to alterations in perception, mood, and cognition, which are characteristic effects of hallucinogens. Peyote contains mescaline, and mushrooms (often referred to as "magic mushrooms") contain psilocybin. MDMA, while primarily known as an empathogen or entactogen, also has hallucinogenic properties at higher doses and is often included in discussions about hallucinogens due to its capacity to alter sensory perception.