Small doses of the psychedelic drug LSD.


Low doses of the psychedelic drug LSD increase complexity in the brain, even when they do not alter a person’s consciousness. The finding challenges the idea that these two phenomena are linked and raises the possibility that even small doses of LSD can have therapeutic effects.

Neural complexity is a measure of the amount of information generated by the brain, with all repetitive signals removed—that is, the smallest number of unique brain signals in a given period of time. Previous studies have shown neurological complications…