Which of the following is listed as a class of psychoactive substances?

• A. Alcohol
• B. Caffeine
• C. Cannabis
• D. Tobacco

Answer: (D)

Psychoactive substances are chemicals that alter brain function, mood, perception, or consciousness. Tobacco is tied to a well-known psychoactive component: nicotine. Nicotine acts on nicotinic acetylcholine receptors in the brain, releasing dopamine and other neurotransmitters, which leads to alertness, mood changes, and reinforcement that can drive dependence. Because of these clear central nervous system effects, tobacco is commonly recognized as a representative example of psychoactive substances. While alcohol, caffeine, and cannabis also affect the brain, the typical classification used in many mental health materials treats tobacco (via nicotine) as the classic psychoactive option in this context.