The psychedelic brew ayahuasca has little effect on sleep quality, according to a study published in Psychopharmacology in 2008.
Twenty-two healthy male volunteers who had previous experience with psychedelic drugs were recruited for participation in this study. The participants were screened for psychiatric disorders, including sleep disorders and substance abuse problems.
These participants randomly received three different drugs, amphetamine, a freeze-dried form of ayahuasca, and a placebo, on three separate occasions. On each testing day, the participant would arrive at the laboratory at 7:00AM, eat a small breakfast, be administered a drug (or placebo) at 12:00PM and then stayed at the laboratory until 12:00PM of the following day. While asleep, the participant’s brainwaves were monitored with an EEG machine.
As expect, amphetamine was found to cause a delay in the onset of sleep stages. Ayahuasca, on the other hand, did not differ from placebo in the onset of stage 1 or stage 2 sleep, but it tended to cause the duration of stage 2 sleep to be longer while making the onset of REM sleep later and its duration shorter. In the authors own words, ayahuasca “did not induce a deterioration of sleep, and no significant effects on sleep initiation or maintenance variables were evidenced. However, like d-amphetamine, ayahuasca increased stage 2, decreased REM stage duration and showed a trend to increase REM latency.”
Barbanoj, M.J., Riba, J., Clos, S., Gimenez, S. Grasa, E. & Romero, S. (2008). Daytime Ayahuasca administration modulates REM and slow-wave sleep in healthy volunteers. Psychopharmacology, Vol 196: 315–326.