Psychedelics are showing increasing promise in treating a range of psychiatric illnesses, from depression to post-traumatic stress disorder (PTSD). But these drugs traditionally have one major drawback: hallucinogenic side effects that could complicate recovery.


However, scientists have now identified a compound that could prompt psychedelic benefits in the brain without the potential bad trip.

As published in Cell journal, the discovery was made due to psychLight, a new genetically encoded fluorescent sensor that can predict whether a molecule could activate serotonin receptors likely to cause hallucinations.

When testing the compound (called AAZ-A-154) on mice, the researchers found it caused antidepressant activity in the brain.

But there is no indication if these results will be replicated on humans. Also, scientists are unsure whether patients would be able to gain the full benefit of psychedelics without hallucinations.

Read more about psychedelics and mental health:

Some experts have advocated using psychedelic drugs to treat select mental illnesses as they have been shown to promote neural plasticity, effectively allowing the brain to re-wire itself. However, psychedelic drugs can cause distressing hallucinations when they interact with receptors that bind to mood-altering neurotransmitters.

"One of the problems with psychedelic therapies is that they require close guidance and supervision from a medical team. A drug that doesn't cause hallucinations could be taken at home," Professor David E Olson, one of the study’s co-authors, said of the new compound’s potential.

“If proven effective, this approach could lead to a drug that works in a single dose or a small number of doses, rather than having to be taken indefinitely.”

Following from pilot studies, scientists are also researching how psychedelics such as psilocybin could be used to treat smoking, alcohol dependence and depression. A small study from Johns Hopkins and New York University also showed how a single 25 mg dose of the drug reduced the anxiety and depression of terminally ill people.


WARNING: Psilocybin and hallucinogenic mushrooms are a Class A drug according to UK law. Anyone caught in possession of such substances will face up to seven years in prison, an unlimited fine, or both. More information and support for those affected by substance abuse problems can be found at


Thomas Ling
Thomas LingDigital editor, BBC Science Focus

Thomas is Digital editor at BBC Science Focus. Writing about everything from cosmology to anthropology, he specialises in astronomy and the latest psychology, health and neuroscience discoveries. Thomas has a Masters degree (distinction) in Magazine Journalism from the University of Sheffield and has written for Men’s Health, Vice and Radio Times. He has been shortlisted as the New Digital Talent of the Year at the national magazine Professional Publishers Association (PPA) awards. Also working in academia, Thomas has lectured on the topic of journalism to undergraduate and postgraduates at The University of Sheffield.