What term refers to substances that affect mental processes and behavior?

The term "psychoactive substances" is used to describe a broad category of substances that have the ability to alter mental processes, state of consciousness, perception, mood, or behavior. These substances can include drugs such as alcohol, caffeine, nicotine, prescription medications, and illicit drugs. They impact the central nervous system and can lead to changes in how individuals think, feel, and behave, making the term comprehensive and encompassing various classes of drugs that influence mental states.

While stimulants, hallucinogens, and antidepressants are all types of psychoactive substances, they represent more specific categories within that broader classification. Stimulants increase alertness and energy; hallucinogens induce altered states of perception and consciousness; and antidepressants are specifically designed to treat mood disorders. However, it is the term "psychoactive substances" that encapsulates all these effects and classifications together, marking it as the most appropriate term in this context.