The psychedelic substance psilocybin causes transient changes in the sleep-wake architecture of laboratory mice, according to new preliminary research published in Translational Psychiatry. The results provide new details on how the drug affects sleep-related brain activity.
“There is evidence that, given the right circumstances, psychedelics such as psilocybin can rapidly relieve the core symptoms of various psychiatric disorders, such as depression, even in severe cases that are resistant to current treatments,” said study author Vladyslav V. Vyazovskiy. Professor of Sleep Physiology at the University of Oxford. “But the neurophysiological mechanisms underlying the beneficial effects of psychedelics are unknown.”
Vyazovskiy and his colleagues were interested in investigating the possible effects of psilocybin on sleep because “insomnia contributes to both the onset and persistence of many mental illnesses,” he explained. Animal models can help better understand the mechanisms underlying psilocybin’s effects on sleep.
“The possible interaction between sleep regulation and the effects of psychedelic compounds has received very little attention, although there are common mechanisms in the underlying biology, such as B. serotonin signaling and synaptic plasticity,” said Vyazovskiy. “Sleep is rarely, if ever, considered a potentially important factor influencing response to psychedelics, which is surprising given that sleep is often disrupted in mood disorders.”
For their study, Vyazovskiy and his colleagues implanted electrodes in mice before injecting them with psilocin (the metabolite of psilocybin) and monitoring their sleep patterns.
After administering psilocin during a time when the mice were normally asleep, the researchers observed that the animals had trouble getting back to sleep. “Psilocin-affected mice spent a significant amount of time in their nests, adopting an attitude consistent with sleep, but still appeared to be awake by electrophysiological criteria,” they explained.
The researchers also found that psilocin delayed the onset of rapid eye movement (REM) sleep and reduced the maintenance of non-rapid eye movement (NREM) sleep for up to three hours after ingestion. “This form of the sleep disorder resembles an increased propensity for brief awakenings, usually defined in mice as waking periods of ≤ 20 seconds that occur during NREM sleep and are typically accompanied by small body movements,” they wrote. But sleep-wake activity seemed to return to normal after about 4 hours.
“We see changes in sleep state and brain activity during sleep after exposure to psychedelics, which may inform us about the underlying neurophysiological mechanisms of psychedelic effects,” Vyazovskiy told PsyPost. “Sleep is an essential part of physiology, it should not be neglected when thinking about health, especially in the brain.”
The results are consistent with a previous human study that found that psilocybin delayed the onset of REM sleep, the sleep phase when most dreams occur, during the first night after administration.
The new study offers more evidence on how psychedelic substances affect sleep activity, but more research is needed. “Our study was conducted on animals, so it is not known whether similar effects occur in humans,” Vyazovskiy noted. “Furthermore, the animals were ‘normal’ (we didn’t look at any models of psychiatric disorders), so we also don’t know how the presence of sleep disorders, as seen in mental disorders, might affect the brain’s response to psychedelics.”
“It remains to be investigated whether the relationship between sleep and psychedelic effects is bi-directional,” he added. “For example, we should address the possibility that sleep plays an important role in consolidating the beneficial psychological effects of psychedelics and is important in long-term recovery from mental illness. Also, the possibility that there are circadian effects on how you respond to psychedelics (in terms of your body clock) has not been explored and should be considered in future research.”
The study “Psilocin Acutely Alteres Sleep-Wake Architecture and Cortical Brain Activity in Laboratory Mice” was authored by Christopher W. Thomas, Cristina Blanco-Duque, Benjamin J. Bréant, Guy M. Goodwin, Trevor Sharp, and David M. Bannerman , and Vladyslav V. Vyazovskiy.