A new study reveals how psychedelics can physically reshape our brains to help fight depression

• Psychedelics are being tested to see if they can help with depression and other mental illnesses.
• A study published in Science shows how psychedelics can physically change brains. 
• The study showed that psychedelics helped grow the "branches" of brain cells, when tested in animals.

Psychedelics have long held a reputation for reshaping minds and evoking mind-altering experiences.

A new study sheds light on how exactly that happens. 

The study, published on Thursday in the prestigious journal Science, shows how certain psychedelic compounds can get inside brain cells and cause them to regrow their connective links. It's based on research in animals and lab tests.

Scientists already know that substances like MDMA, LSD, and psilocybin — the psychoactive compound found in magic mushrooms — hold promise as treatments for mental illnesses like depression and anxiety. What this study adds is new insight on how exactly these compounds work in the brain and why they may help patients.

Brain cells look something like a tree, and the branches that each cell has are called dendrites. Dendrites are responsible for receiving signals from other brain cells and play an essential role in how our brain functions. Damaged brain cells and their branches have been connected to a wide range of brain disorders, from neurodegenerative diseases like Alzheimer's disease to psychiatric illnesses like depression and post traumatic stress disorder.

The study showed that psychedelics like DMT and psilocin, the active form of psilocybin, can help grow the "branches" that may have atrophied over time.

In cell cultures, psychedelics prompted neurons to regrow their dendrites. Treatments that prompt these neurons to regrow may then play a role in treating mental illnesses. 

David Olson, the senior author on the study, told Insider that the study showed that psychedelics like psilocybin and DMT can act inside brain cells. Olson is the director of the Institute for Psychedelics and Neurotherapeutics at UC Davis and is also cofounder of psychedelics startup Delix Therapeutics, which is working to develop psychedelic-like compounds that don't cause hallucinations as possible new treatments for mental illnesses. 

Many antidepressants on the market are selective serotonin reuptake inhibitors, or SSRIs, and work by increasing levels of serotonin in the brain. While these drugs have shown to thicken the dendrites in the brain over time, they take a long time to start working. 

Olson said the study shows that there are differences in how psychedelics act in the brain, compared to serotonin, suggesting that psychedelics could have some unique advantages as treatments. 

It's all about "location, location, location," Olson said. "I think it's very clear that psychoplastegen-based medicines will have a more robust response in terms of cortical neuron growth than serotonin-based medicine." 

He said that as we develop a better understanding of how exactly the brain cells work and can regrow, that can help guide new treatments for illnesses like depression and PTSD.

A commentary published alongside the study noted that while this research is a "key achievement in the understanding of the mechanism of action of psychedelics," more research to better understand the relevance of this finding in humans is needed.

Further research should study how exactly psychedelics work inside cells to foster the regrowth of brain cells and what effect these changes have on brain function, it said. 

But it added: "These findings are an important step forward for a rapidly expanding and much-needed field of study."