Lysergic acid diethylamide, commonly referred to as LSD, or “acid,” is considered the best known and most researched psychedelic drug. LSD is active at exceptionally small doses (around 20 micrograms) and is taken orally, sometimes as droplets or more commonly on blotter paper and absorbed on the tongue and then swallowed. LSD was discovered in 1938 by Albert Hofmann, a Swiss chemist. The effects Hofmann reported included, “restlessness,  dizziness, a dreamlike state and an extremely stimulated imagination.” For the next two decades, thousands of experiments with LSD led to a better understanding of how LSD affected consciousness by interacting with the brain’s serotonin neurotransmitter system. Scientists considered psychedelics to be promising treatments as an aid to therapy for a broad range of psychiatric diagnoses, including alcoholism, schizophrenia, autism spectrum disorders, and depression. Recent results from epidemiological studies have shown lower rates of mental health disorders and suicide among people who have used psychedelics like LSD. The effects of psychedelic drugs like LSD are difficult to categorize – they affect different people, at different places, and at different times, with incredible variability. However, LSD and other psychedelics are known for their profound changes in consciousness and perception. LSD’s effects last around 8-10 hours, with peak effects occurring 4-6 hours after ingestion. These effects include sensory enhancement, sense of time changing (minutes can feel like hours), real or imagined objects appear to be moving (flowing patterns and shapes) both with eyes open or closed, unusual thoughts and speech, personal insight and reflection, and excited mood. Individual reactions to these perceptual changes are very much based on set and setting. Set (or “mindset”) refers to the psychological state and the beliefs of the person taking the drug. Setting is the external circumstances they’re in – the people around them and their environmental surroundings. References: • LSD Fact Sheet