Final answer:
LSD is a hallucinogenic drug that alters mood and perception by disrupting neurotransmitter systems in the brain.
Step-by-step explanation:
LSD, or Lysergic acid diethylamide, is a hallucinogenic drug that alters a person's mood and perception. It is synthesized from lysergic acid, which is derived from a rye fungus. LSD can cause hallucinations, profound distortions in reality, and rapid, intense emotional swings. It works by temporarily disrupting communication between neurotransmitter systems that regulate mood, sensory perception, sleep, hunger, and other functions.