Which is a class of psychoactive substances?

Which is a class of psychoactive substances?

• A. Alcohol
• B. Water
• C. Oxygen
• D. Sand

Answer: (A)

Psychoactive substances are chemicals that act on the brain to change mood, perception, or behavior. Alcohol fits this category because it is a central nervous system depressant that alters neurotransmitter activity—enhancing GABA’s inhibitory effects and dampening glutamate’s excitatory effects. This combination slows thinking, reduces inhibitions, and impairs coordination, which are hallmark psychoactive effects. The other options don’t change mental state in normal use: water, oxygen, and sand are not substances that alter mood or perception in everyday contexts.

Psychoactive substances are chemicals that act on the brain to change mood, perception, or behavior. Alcohol fits this category because it is a central nervous system depressant that alters neurotransmitter activity—enhancing GABA’s inhibitory effects and dampening glutamate’s excitatory effects. This combination slows thinking, reduces inhibitions, and impairs coordination, which are hallmark psychoactive effects. The other options don’t change mental state in normal use: water, oxygen, and sand are not substances that alter mood or perception in everyday contexts.