Scientists at the University of California are conducting research to understand how hallucinogenic drugs affect the brain, potentially opening doors in the future to include psychedelics in the treatment of depression and other mental disorders.

Their latest findings demonstrated the ability of the drugs to alter brain cells in rats and flies, increasing the connectivity between neurons. The study titled "Psychedelics Promote Structural and Functional Neural Plasticity" was published in the journal Cell Reports on June 12.

While depression is typically associated with chemical imbalances in the brain, studies from recent years identified how structural changes in parts of the brain may also play a role. For example, the hippocampus was found to be 9 to 13 percent smaller among depressed people in one fMRI study. 

The authors of the new research explained how neurons do not die when one experiences depression. Instead, the neurites — the part of the neuron which branches out and connects itself to other neurons — simply retract.

Senior author David E. Olson explained how shriveled up neurites in the prefrontal cortex (the brain region which regulates emotion and mood) is “one of the hallmarks” of depression.

“People have long assumed that psychedelics are capable of altering neuronal structure, but this is the first study that clearly and unambiguously supports that hypothesis,” he said. “What is really exciting is that psychedelics seem to mirror the effects produced by ketamine.”

Ketamine has been shown to have antidepressant properties, though the drug had a number of limitations such as the rapidly fading effects and the high cost of treatment. Olson and co-researchers demonstrated how psychedelics could mimic the effects of ketamine on neurons grown in a dish. 

After being treated with a dose of the psychedelic compound DMT, rats exhibited an increase in the number of dendritic spines, similar to that seen with ketamine treatment. While the drug was eliminated within an hour, the “rewiring” effects on the brain of the rats remained even after 24 hours.

Olson and his team also showed DMT treatment helped rats overcome a “fear response” to the memory of a mild electric shock. This may potentially offer clues to help in designing treatments for post-traumatic stress disorder.

"These are some of the most powerful compounds known to affect brain function, it's very obvious to me that we should understand how they work," said Olson. 

But alongside encouraging findings, it must be acknowledged that psychedelics still carry a few risks. For one, the drugs could trigger psychotic disorders in people who are genetically at risk.

Richard A. Friedman, a professor of clinical psychiatry at the Weill Cornell Medical College, stated psychedelics can be behaviorally toxic, if not addictive like cocaine or alcohol. In addition to their “high abuse potential,” he explained the safety and efficacy have remained unclear since most data is anecdotal or derived from small trials.

“Psychedelics might turn out to have real promise, but that needs to be proven through large, rigorous, placebo-controlled trials. We’re not there yet,” he cautioned.