Final answer:
Psychoactive drugs that blur the distinction between fantasy and reality, such as hallucinogens or dissociative drugs, cause profound distortions in perception. They can lead to hallucinations and altered emotional states by acting on neurotransmitters in the brain.
Step-by-step explanation:
Psychoactive drugs are substances that have an impact on brain chemistry, altering mood, thinking, perception, and behavior. When a psychoactive drug makes the distinction between fantasy and reality less clear, it is often referred to as a hallucinogen or a dissociative drug.
Misuse of these drugs can lead to addiction, characterized by compulsive use despite negative consequences and possibly leading to physical or psychological dependence. Treatment often involves psychotherapy and sometimes the controlled use of other psychoactive drugs to aid in rehabilitation.