Psychedelic drugs such as LSD seem to make brain cells grow branches and form new connections.
The finding in rats and fruit flies could explain why psychedelics seem to evoke long-lasting changes after a single dose, and why they may be able to help treat mental health disorders.
The psychedelics include psilocybin, found in magic mushrooms, and DMT, found in the South American plant brew ayahuasca. In recent years, numerous studies have investigated these drugs as a possible treatment for depression, and small trials have had promising results.
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Studies have also reported that some users undergo after a single psychedelic experience.
The drugs activate serotonin receptors in the brain, but how they bring about long-lasting changes is unknown. Some researchers have speculated that they might increase the brain鈥檚 ability to rewire itself, known as plasticity.
David Olson at the University of California, Davis and colleagues tested three psychedelic drugs: LSD, DMT and DOI, on rats and fruit flies. All three increased the growth of new branches on neurons and new connections between neurons, both in isolated cells and in live animals.
The fact that the same effects were seen in vertebrates and invertebrates suggest that the biological mechanisms involved have remained the same over aeons of evolution, and are probably the same in humans, believes Olson.
Fast effect
In rats, the drugs increased the density of neuronal projections in the prefrontal cortex of the brain. Depression has been linked to the shrinking of neurons and loss of connections in the same region.
鈥淔inding compounds that rapidly regrow these neurons I think is going to be our best bet for treating that disease,鈥� says Olson.
Ketamine, a drug with some similarities to psychedelics which also seems to lift depression in clinical trials, may also work by increasing plasticity in a short space of time. More established antidepressants take much longer 鈥� weeks or months 鈥� to have a similar effect.
Olson hopes that learning how psychedelics promote plasticity will enable the development of new compounds that mimic these effects without the more trippy ones. 鈥淚 don鈥檛 think psychedelics are ever going to be a viable therapeutic, but I think they can be used as inspiration to develop safer, more efficacious versions,鈥� he says.
Cell Reports
Read more: Mind menders: how psychedelic drugs rebuild broken brains
