Psychedelics are a class of psychoactive substances that alter perception, mood, and cognition. Common psychedelics include LSD, psilocybin (magic mushrooms), DMT, and mescaline. These substances affect serotonin receptors in the brain, often leading to hallucinations, altered sense of time, and deep introspective experiences. Research suggests potential therapeutic benefits for mental health conditions like depression, PTSD, and anxiety, but they also carry risks such as psychological distress and impaired judgment. Psychedelics should only be used in safe, controlled environments and under professional guidance where applicable.