“As a general anesthetic, propofol acts on the brain’s GABA receptors, which cause inhibitory neurons—those that quiet other circuits—to fire; that’s how it induces unconsciousness. Propofol also increases levels of the feel-good neurotransmitter dopamine, triggering a sense of reward not unlike sex or cocaine. Some patients experience euphoria, sexual disinhibition, and even hallucinations, followed by a feeling of calm and an upbeat mood. Since propofol is so widely used—it revolutionized ambulatory anesthesia, allowing a physician to knock someone out in seconds to perform, say, a colonoscopy, and have them up and about after only 10 minutes—scientists have had no shortage of subjects able to describe the experience. About one third don’t remember a thing, and another third say they dreamed, but don’t recall specifics. The rest experience “vivid, strange dreams, sometimes of a sexual nature.”—
