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Sunday, May 17, 2026

Trip to recovery: How psychedelics could revolutionise mental health care

By Amber Louise Bryce

Published on 17/05/2026 - EURONEWS

In a world gripped by a growing mental health crisis, research suggests that psychedelic-assisted therapy could be an answer. Euronews Health spoke to an expert about how they work, and when - if ever - we might see them approved.

Picture this: You walk into a small, dimly lit room and lay on a bed beside a clinician. After talking you through what’s going to happen, they hand you an eye mask, then administer a controlled dose of the psychedelic compound, psilocybin.

As suddenly as the drug takes effect, the world as you knew it starts to dissolve - the chains of old thought patterns finally loosen.

While it might sound intense, this scenario could be a future reality for those living with treatment resistant mental illness, including depression and post traumatic stress disorder (PTSD).

In recent years, psychedelic-assisted therapies have become one of the most fascinating and fast-accelerating areas of psychiatric research, driven by an ever-growing body of exciting new evidence.

The current mental health crisis has also created an urgency for new, more effective treatment options, with over a billion people currently living with mental health disorders, according to the World Health Organization (WHO).

“Unfortunately, in mental health, and specifically in psychiatry, we haven't really had any new treatments for several decades,” Dr Liliana Galindo, an assistant professor at the University of Cambridge’s psychiatry department, told Euronews Health.

“What psychedelics are bringing is the opportunity to have or to present new treatments for people that don't respond to the usual treatments.”

Psychedelics are a class of psychoactive substances that can powerfully alter people's perceptions and moods by binding to serotonin receptors. Popular examples include psilocybin, DMT, phenethylamines (MDMA) and lysergamides (LSD).

While they all share similar consciousness-expanding qualities, each compound varies in its intensity, duration, and overall effect, with different ones being tested for different conditions.

So far, psilocybin, an active ingredient in magic mushrooms, has generated the most promising results.

“For treating depression, psilocybin, specifically the COMP360 (a synthetic formulation of psilocybin developed by Compass Pathways), has already finished phase three of its clinical trials. We are expecting that [Compass] is going to file the FDA (Food and Drug Administration) application soon,” Galindo said.

“Potentially, this could be the very first psychedelic treatment that will be legal and approved.”

How do psychedelic-assisted therapies work?

Up until now, mental health treatments have relied on two evidence-based methods: talk therapies and medications such as antidepressants.

These are proven to be effective, with patients receiving a combination of the two 25-27% more likely to respond positively, according to statistics by the National Institutes of Health.

But for those that don’t respond, other avenues of help remain limited.

“Many mental health conditions have some symptoms that are common, like rigid cognitions. So, for example, when people are depressed, they start to have really negative thoughts, and these negative thoughts are going to affect how they see themselves, how they see the world, and of course, how they are going to feel about it. And after several years of being depressed, it's really difficult to take a step outside of those pessimistic thoughts, or frequent fears and even suicidal ideations,” Galindo explained.

For these cases, psychedelic medications could be the answer, with Galindo noting their effectiveness at disrupting cognitive ruts and rewiring how the brain processes trauma.

“I really like an analogy I saw once [about psychedelic medications] that it's like when you're skiing. You usually go for a certain pathway, right? And because the pathway has a specific mark, it is really difficult to actually go outside of it. But somehow, what psilocybin allows, is like having fresh snow that will make it easier to actually explore different pathways.”

Numerous studies back this, with a recent one by Imperial College London - considered a world leader in psychedelic research - reporting that even a single dose of psilocybin can prompt anatomical changes in the brain.

Other psychoactive compounds such as MDMA have been shown to work a little differently by enhancing feelings of empathy, connectivity and openness, which could be effective at treating PTSD.

“It facilitates a period of time where people [with PTSD] can revisit their memories and somehow be able to rethink, to reframe, to change the narrative and to process their trauma,” she said.

“This is the reason psychedelics are bringing such a big revolution to mental health, because they're aiming to treat the core rather than only the symptoms.”

Social stigmas and legal issues

A major hurdle to mainstream approval, however, remains their status as illegal drugs in most countries.

“Unfortunately, even if we have clear evidence for their therapeutic potential, they are still illegal. For example, here in the UK, they're still classified A, meaning that in order to conduct any study, we need to apply for a special home office licence. This is not only expensive, but takes a long time, and so is definitely affecting the amount of research that could be happening in the field,” Galindo said.

Another issue is the stigmas surrounding these drugs, and their primary associations with party culture and potentially dangerous outcomes.

Galindo emphasises that these concerns are why the controlled setting of psychedelic-assisted therapies is so important.

“You need to take care of all the different details of the environment, like the sound, the lights. And of course, the entire time [the patient] is supported by a trained therapist or a member of the staff that is there to be able to support during that process,” she said.

“These drugs are really powerful tools, but of course, if for any reason they are not given in the right setting, this could come with more side effects.”

While more research is required to better understand who will benefit and who won’t, Galindo hopes that, one day, these treatments can become an accessible option for everyone.

“Rather than staying in a private setting, they should be available for the people who need it the most, not only for the ones that can pay.”

Tuesday, May 05, 2026

Cannabis microdosing more common than psychedelics among US adults, national survey finds

Across substances, people reporting poorer mental health were more likely to report microdosing

University of California - San Diego

Key takeaways:

Cannabis is the most commonly microdosed substance in the U.S., with about 9.4% of adults — roughly 24 million people — reporting lifetime use. More people reported microdosing for recreational reasons than for medical reasons.

Cannabis microdosing was nearly twice as common as psilocybin, LSD or MDMA, challenging the perception that microdosing is mainly a psychedelic practice.

Microdosing was more common among people reporting poorer mental health.

Researchers from University of California San Diego have found that microdosing — taking very small amounts of psychoactive substances — is more common among U.S. adults than previously recognized, with cannabis leading by a wide margin. The study, published May 4, 2026 in the American Journal of Preventive Medicine, estimates that millions of Americans have microdosed substances such as cannabis, psilocybin, LSD (“acid”) and MDMA (“ecstasy”).

“Microdosing is often discussed in the context of psychedelics like psilocybin or LSD, but what surprised us most was that cannabis microdosing was almost twice as common,” said Kevin Yang, MD, resident physician in the Department of Psychiatry at UC San Diego School of Medicine and first author of the study. “That suggests conversations about microdosing may be overlooking a large group of people who are using small amounts of cannabis in similar ways.”

“Most proponents of microdosing recommend use under specific protocols that involve taking low doses of LSD or psilocybin for specific health applications,” said Eric Leas, PhD, MPH, assistant professor at the UC San Diego Herbert Wertheim School of Public Health and Human Longevity Science and senior author of the study. “That’s not what we found. Most people are microdosing for recreational purposes. That suggests that many people could think about the concept of ‘microdosing’ more as a way of lowering dosage. They may just want to take less, so they don’t want to get as high.”

Microdosing typically involves consuming about one-fifth to one-twentieth of a typical recreational dose, with the goal of avoiding strong psychoactive effects while potentially experiencing subtler benefits such as improved mood, reduced anxiety or enhanced creativity.

To better understand how common the practice is, researchers analyzed data from a nationally representative survey of 1,525 U.S. adults conducted in late 2023 through the Ipsos KnowledgePanel, which uses probability-based sampling to reflect the U.S. population. Participants were asked whether they had ever intentionally microdosed cannabis, psilocybin mushrooms, LSD or MDMA.

The results suggest that cannabis is the most commonly microdosed substance. About 9.4% of U.S. adults — an estimated 24.1 million people — reported microdosing cannabis at least once in their lifetime. In comparison, 5.3% reported microdosing psilocybin, 4.8% LSD and 2.2% MDMA.

Ongoing microdosing was less common but still measurable: roughly 3.3% of adults reported currently microdosing cannabis, compared with about 1.0% for psilocybin, 0.6% for LSD and 0.3% for MDMA.

The study also found that the reasons for microdosing differed by substance. Cannabis microdosing was most often reported for medical reasons, including managing anxiety, depression or chronic pain. In contrast, psilocybin, LSD and MDMA were more frequently microdosed for recreational purposes, such as achieving a milder psychoactive experience.

Researchers also observed patterns tied to mental health and policy environments. Across substances, people reporting poorer mental health were more likely to report microdosing. For example, cannabis microdosing was reported by about 21% of adults who rated their mental health as “poor,” compared with about 8% among those reporting “excellent” mental health.

In addition, microdosing of psychedelics such as psilocybin and LSD was more common in places where laws were more permissive — meaning, jurisdictions that have decriminalized psychedelic possession. The findings suggest that changes in drug policy may influence both access to these substances and people’s willingness to report using them.

Despite growing public interest, the researchers emphasize that scientific evidence on the health effects of microdosing remains limited. Few placebo-controlled clinical trials have been conducted and existing studies have produced mixed findings about potential benefits. Additional risks stem from the unregulated nature of many of these substances, including the possibility of adulterated products or dosing errors — especially since most people who microdose do not test the substances they use.

“There’s a lot of anecdotal enthusiasm around microdosing, especially for mental health,” said Leas. “But we still need rigorous studies to determine whether these perceived benefits are real, who might benefit and what the potential risks could be.”

The authors note that because the study was cross-sectional, it cannot determine whether microdosing influences mental health outcomes or whether people experiencing mental health challenges are more likely to try microdosing. Future research, including longitudinal studies and clinical trials, will be needed to clarify those relationships.

As cannabis legalization and psychedelic policy reforms continue to evolve across the United States, the researchers say monitoring patterns of microdosing will become increasingly important for public health.

“Microdosing appears to be a growing behavior that cuts across different substances and motivations,” Leas said. “Understanding how and why people are using these small doses is essential if we want to develop evidence-based policies and guidance for clinicians and the public.”

Link to full study: https://doi.org/10.1016/j.amepre.2026.108381

Additional co-authors on the study include: Joseph Friedman, MD, and Siyuan Ping from UC San Diego. Nora Satybaldiyeva, PhD, and Wayne Kepner, PhD, from Stanford University.

The study was funded, in part, by the U.S. National Institute on Drug Abuse (grant #K01DA054303, PI: Leas). Satybaldiyeva acknowledges salary support from the National Heart, Lung, and Blood Institute (grant #5T32HL161270-03). Kepner acknowledges salary support from the National Institute on Drug Abuse of the National Institutes of Health (#T32DA035165), and the William and Katharine Duhamel Addiction Medicine Fund.

Authors declare no competing interests.

Journal

American Journal of Preventive Medicine

DOI

10.1016/j.amepre.2026.108381

Tuesday, April 28, 2026

Reclassifying marijuana as a less dangerous drug might only be the first step for Trump

By The Associated Press
Published: April 24, 2026

SEATTLE — U.S. President Donald Trump’s decision to reclassify state-licensed medical marijuana as a less dangerous drug is a boon for the industry: It gives dispensaries a big tax break, eases some barriers to researching cannabis and could even allow the export of marijuana to other countries.

But that might only be Trump’s first step. A new administrative hearing slated for the end of June could result in the reclassification of marijuana more broadly, granting tax and other benefits to state-licensed recreational markets, too.

“This is a signal that this administration means business on getting this done,” said Boston-based cannabis industry attorney Jesse Alderman, of the firm Foley Hoag.

The order issued Thursday does not legalize marijuana for medical or recreational use under federal law, and it is likely to face legal challenges.

But it does change the way marijuana is regulated, shifting licensed medical marijuana from Schedule I — reserved for drugs without medical use and with high potential for abuse — to the less strictly regulated Schedule III.

A long-sought shift

It was a significant policy shift for a U.S. government that has been steadfast in its prohibition of pot, even as all states but two — Idaho and Kansas — have approved cannabis in some form since California became the first to OK the medical use of marijuana in 1996.

Two dozen states plus Washington, D.C., have authorized adult recreational use of marijuana, raising billions in tax revenue. Forty have medical marijuana systems, and eight others allow low-THC cannabis or CBD oil for medical use.

The order noted that regulation of medical marijuana has come a long way, with comprehensive licensing polices from cultivation to sales in most states.

Douglas Hiatt, a longtime Seattle marijuana defence attorney, recalled the height of the AIDS epidemic in the 1980s and ’90s, when police regularly raided grow operations designed to support patients.

He joined one client, a disabled medical marijuana activist named JoAnna McKee, as she met in the woods with members of the Hells Angels motorcycle club to procure cannabis for other patients after a police raid — just one example of the desperate lengths that were sometimes required to procure pot back then, he said.

“We were watching all these guys die from this horrible disease, and the only thing that helped them keep their pills down was marijuana, and the cops were going after anyone who helped them get it,” Hiatt said in a phone interview Thursday. “It was crystal clear from the beginning that it had medical uses. For the feds to admit that now is great. It’s surreal.”
Critics express doubts

Some health experts have suggested that legalization in the states has led to stronger and stronger cannabis products, which need to be researched rather than categorized less strictly than before.

Taking marijuana from a Schedule I drug to a Schedule III drug implies that it’s useful as a treatment, but there are no “massive medical indications for cannabis,” said Dr. Smita Das, an addiction psychiatrist at Stanford University. Further, cannabis use disorder — which affects about 3 in 10 people who use pot, according to the U.S. Centers for Disease Control and Prevention — has been on the rise, she said.

“We’ve already had kind of a decrease in risk perception related to cannabis over the years with the state legalization,” Das said. ”This will probably just add to that.”

The reclassification is a far cry from what many critics of the drug war still long to see: full legalization, with measures to address the harms caused by prohibition, especially in minority communities that were disproportionately affected. Many states have already taken steps such as expunging criminal records.
There is confusion for some dispensaries

Now, state-licensed medical operators can finally deduct business expenses on their federal taxes, a crucial financial benefit.

But in a number of recreational pot states, licensed dispensaries serve both markets — making it an accounting nightmare to ascertain how much of their business expenses might stem from the medical side, and thus be deductible.

“If this artificial distinction between medical and recreational is maintained, it raises all sorts of questions,” noted sociology professor Josh Meisel, who co-founded the Humboldt Institute for Interdisciplinary Marijuana Research at California State Polytechnic University, Humboldt.

Trump told his administration in December to work as quickly as possible to reclassify marijuana, following up on stalled efforts launched during the Biden administration. On Saturday, as the Republican president signed an unrelated executive order about psychedelics, he seemed to express frustration that it was taking so long.
‘Giving a tax break to Big Weed’

The president of the American Trade Association for Cannabis and Hemp, Michael Bronstein, called the order “the most significant federal advancement in cannabis policy in over 50 years.”

But marijuana legalization opponent Kevin Sabet, CEO of Smart Approaches to Marijuana, said that while marijuana research is necessary, “there are many ways to increase our knowledge without giving a tax break to Big Weed.”

Trump has made his crusade against other drugs, especially fentanyl, a feature of his second term, ordering U.S. military attacks on Venezuelan and other boats the administration insists are ferrying drugs.

___

Gene Johnson, The Associated Press

Johnson reported from Seattle.

Associated Press reporter Laura Ungar contributed.

Monday, April 27, 2026

B.C.

TBI survivors turn to psychedelics for symptom relief

Study shows that patients with traumatic brain injuries are seeking alternative supports

University of Victoria

TBI-psychedelics — image:
University of Victoria doctoral candidate Baeleigh VanderZwaag in the lab.
view more
Credit: University of Victoria

A new study from the University of Victoria (UVic) has identified a segment of traumatic brain injury survivors who are using psychedelics to self-medicate for cognitive, mood and somatic symptoms such as headaches.

In a first-of-its-kind study, clinical psychology researchers analyzed more than 6,100 responses collected from the global psychedelic survey. Researchers found that nearly 1,200 respondents reported using psychedelics to treat or manage a physical health condition.

Of these, some 208 participants, or 3.4 per cent of the total sample, reported using psychedelics to manage brain injury-related symptoms.

The paper, Psychedelics for the management of symptoms of traumatic brain injury: Findings from the global psychedelic survey, was published Progress in Neuropsychopharmacology & Biological Psychiatry, co-authored by UVic clinical psychology professors Jill Robinson and Mauricio Garcia-Barrera.

Some 60 million people worldwide experience traumatic brain injuries (TBI) every year. Garcia-Barrera says there isn't a one-size-fits all treatment for TBI survivors, and he says some are looking for alternative supports, including from psychedelics.

“Although research into using psychedelics to manage TBI symptoms remains quite limited, the field is gaining momentum as awareness grows around how widespread brain injury is globally and its impact on the quality of life of those who experience a TBI,” Garcia-Barrera says.

Baeleigh VanderZwaag, the UVic PhD student who led the study, said there is limited research from human participants when it comes to psychedelics and brain injury, with most research coming from animal models. This is the first time a study has examined traumatic brain injury survivors’ self-reported use of psychedelics to treat symptoms.

“I wasn’t expecting so many people to be using psychedelics at this point for brain injury—it's really new information,” says VanderZwaag. “It was surprising to find that some people globally are experimenting with this, acquiring psychedelics by themselves to see how it works for them.”

Researchers found that respondents with TBIs most often used psilocybin every two to five months or every six months to treat their symptoms, using a mix of microdoses and larger doses. Other respondents reported self-medicating with LSD/acid and ketamine.

Not only are people with TBIs experimenting with psychedelics to manage mood, cognitive and somatic symptoms—they are finding relief. When asked to rate how effective their psychedelic use was on their TBI-related symptoms, 90 per cent of the sample self-reported some level of symptom improvement.

A lot of questions remain, however, around the safety and effectiveness of using psychedelics to treat brain injuries. VanderZwaag says more research, including clinical trials, is needed to evaluate the risks and benefits of using psychedelics for TBIs.

Next VanderZwaag and colleagues will analyze new data from the 2025 Global Psychedelic Survey, which was administered in the spring of 2025 and translated into 18 additional languages.

View this release in your browser.

 A media kit containing high-resolution photos is available on Dropbox.

About the University of Victoria

The University of Victoria is a leading research-intensive institution, offering transformative, hands-on learning opportunities to more than 22,000 students on the beautiful coast of British Columbia. As a hub of groundbreaking research, UVic faculty, staff and students are making a significant impact on issues addressing challenges that matter to people, places and the planet. UVic consistently publishes a higher proportion of research based on international collaborations than any other university in North America. Our commitment to advancing climate action, addressing social determinants of health, and supporting Indigenous reconciliation and revitalization is making a difference—from scientific and business breakthroughs to cultural and creative achievements. Find out more at uvic.ca. Territory acknowledgement

UVic news page: www.uvic.ca/news

DOI

10.1016/j.pnpbp.2026.111624

Method of Research

Survey

Subject of Research

People

Article Title

Psychedelics for the management of symptoms of traumatic brain injury: Findings from the global psychedelic survey

University of Victoria doctoral candidate Baeleigh VanderZwaag and psychology professor Mauricio Garcia-Barrera.

University of Victoria doctoral candidate Baeleigh VanderZwaag and psychology professor Mauricio Garcia-Barrera.

University of Victoria doctoral candidate Baeleigh VanderZwaag and psychology professor

University of Victoria doctoral candidate Baeleigh VanderZwaag in the lab.

Friday, April 24, 2026

420 SURPRISE

Trump administration reclassifies medical marijuana as a 'less-dangerous drug'

President Donald Trump’s administration on Thursday reclassified state-licensed medical marijuana as a less-dangerous drug, easing research barriers and granting tax relief. The change falls short of federal legalisation but marks a major shift in US cannabis policy.

Issued on: 23/04/2026 -
By: FRANCE 24

A medical marijuana plant grows at CRC on July 23, 2024, in Pike County, Alabama.

© Kim Chandler, AP

President Donald Trump's acting attorney general on Thursday signed an order reclassifying state-licensed medical marijuana as a less-dangerous drug, a major policy shift long sought by advocates who said cannabis should never have been treated like heroin by the federal government.

The order signed by Todd Blanche does not legalise marijuana for medical or recreational use under federal law. But it does change the way it's regulated, shifting licensed medical marijuana from Schedule I – reserved for drugs without medical use and with high potential for abuse – to the less strictly regulated Schedule III. It also gives licensed medical marijuana operators a major tax break and eases some barriers to researching cannabis.

The Trump administration also said it was jump-starting the process for reclassifying marijuana more broadly, setting a hearing to begin in late June.

Trump told his administration in December to work as quickly as possible to reclassify marijuana. On Saturday, as the Republican president signed an unrelated executive order about psychedelics, he seemed to express frustration that it was taking so long.

Blanche said Thursday that the Department of Justice was “delivering on President Trump’s promise” to expand Americans’ access to medical treatment options. “This rescheduling action allows for research on the safety and efficacy of this substance, ultimately providing patients with better care and doctors with more reliable information,” he said in a statement.
Windfall for medical firms

Blanche's action Iargely legitimises medical marijuana programmes in the 40 states that have adopted them. It sets up an expedited system for state-licensed medical marijuana producers and distributors to register with the US Drug Enforcement Administration.

It makes clear that cannabis researchers won't be penalised for obtaining state-licensed marijuana or marijuana-derived products for use in their work, and it grants state-licensed medical marijuana companies a windfall by allowing them, for the first time, to deduct business expenses on their federal taxes.

Any marijuana-derived medicine approved by the Food and Drug Administration is similarly listed in Schedule III, it said.

Since 2015, Congress has prohibited the Justice Department from using its resources to shut down state-licensed medical marijuana systems. But the order nevertheless represents a major policy shift for the US government, which has continued its longstanding marijuana prohibition – dating to the Marihuana Tax Act of 1937 – even as nearly all the states have approved cannabis use in some form.

Two dozen states plus Washington, DC, have authorised adult recreational use of marijuana, 40 have medical marijuana systems, and eight others allow low-THC cannabis or CBD oil for medical use. Only Idaho and Kansas ban marijuana outright.

The regulation of medical marijuana has come a long way since California became the first state to adopt it in 1996, Blanche wrote.

“Today the vast majority of States maintain comprehensive licensing frameworks governing cultivation, processing, distribution, and dispensing of marijuana for medical purposes,” Blanche wrote. “Taken as a whole, they demonstrate a sustained capacity to achieve the public-interest objectives ... including protecting public health and safety and preventing the diversion of controlled substances into illicit channels.”

The president of the American Trade Association for Cannabis and Hemp, Michael Bronstein, called it “the most significant federal advancement in cannabis policy in over 50 years".
'Cannabis is medicine'

“This action recognises what Americans have long known, cannabis is medicine,” he said in a written statement.

The Trump administration’s decision drew derision from marijuana legalisation opponent Kevin Sabet, the chief executive of Smart Approaches to Marijuana. Sabet said that while marijuana research is necessary, "there are many ways to increase our knowledge without giving a tax break to Big Weed and sending a confusing message about marijuana’s harms to the American public".

“With this move, we are now confronted with the most pro-drug administration in our history,” Sabet said in a text message. “Policy is now being dictated by marijuana CEOs, psychedelics investors, and podcasters in active addiction."

Marijuana or marijuana-derived products that are not distributed through a state medical marijuana programme will continue to be classified in Schedule I.

Schedule III drugs are defined as having moderate to low potential for physical and psychological dependence. Some critics of the industry have suggested that legalisation in the states has led to stronger and stronger cannabis products, which need to be researched rather than categorised less strictly than before.

The Justice Department under President Joe Biden, a Democrat, had proposed to reclassify marijuana, eliciting nearly 43,000 formal public comments. The DEA was still in the review process when Trump succeeded Biden, and Trump ordered that process to move along as quickly as legally possible.

Blanche's order sidestepped the review process by relying on a provision of federal law that allows the attorney general to determine the appropriate classification for drugs that the US must regulate pursuant to an international treaty.

It was unclear how the order might affect operations in states where licensed recreational marijuana shops also sell to medical patients. In Washington state, which in 2012 became one of the first states to legalise the adult use of marijuana, 302 of 460 licensed stores have endorsements allowing them to sell tax-free cannabis products to registered patients.

Many Republicans oppose loosening marijuana restrictions. More than 20 Republican senators, several of them staunch Trump allies, signed a letter last year urging the president to keep the current standards.

Trump has made his crusade against other drugs, especially fentanyl, a feature of his second term, ordering US military attacks on Venezuelan and other boats the administration insists are ferrying drugs. He signed another executive order declaring fentanyl a weapon of mass destruction.

(FRANCE 24 with AP)

Thursday, April 09, 2026

Largest-ever study of psychedelics could help advance their use in treating mental health disorders

Researchers have discovered that despite different chemistries, five psychedelic compounds affect the brain in two similar ways

McGill University

Scientists have demonstrated, for the first time, that several psychedelic drugs – including psilocybin, LSD, mescaline, DMT and ayahuasca – produce a common pattern of brain activity despite their distinct chemistries.

An international consortium led by a McGill University researcher pooled brain imaging data from labs across five countries, creating the largest study of its kind to date.

The findings, published in Nature Medicine, could help guide the design of future treatments for mental health disorders.

“This is a breakthrough in how we think about psychedelic drugs,” said senior author Danilo Bzdok, Associate Professor in McGill’s Department of Biomedical Engineering and Canada CIFAR Artificial Intelligence Chair at Mila. “For the first time, we show there’s a common denominator among drugs that we currently consider completely separate.”

Two measurable changes in the brain

While different psychedelics have shown benefits for some mental health conditions, how they produce similar effects despite their chemical differences remains a mystery. The meta-analysis identified two consistent neural effects across five of the most common drugs.

Normally, each brain system communicates strongly within itself, maintaining tight, organized networks. The researchers found that under the influence of psychedelics, these connections weaken, making the networks less rigidly structured.

The second neural effect is that psychedelics increase communication between different brain networks, allowing signals to cross boundaries that are usually separate. This “cross-talk” may help explain the hallucinations and other unusual thoughts, sensations and perceptions people report during psychedelic experiences.

An ‘X-ray’ of global psychedelic research

The meta-analysis combined results from 11 datasets, analyzing more than 500 brain imaging sessions from 267 participants.

Psychedelic neuroscience studies are typically small, often limited to 10 to 30 participants because of high costs and strict regulations. Studying five different psychedelics in a single experiment would be nearly impossible, the authors note.

“This approach gives us an X-ray view of the entire research community,” said Bzdok.

The thawing of ‘psychedelic research winter’

Interest in psychedelics for mental health treatment has surged in recent years, fuelled in part by advances in brain imaging technologies. The revival follows what authors call the “psychedelic research winter” of the 1970s, when studies were limited by criminalization and associations with counterculture.

“Many drug therapies for depression, for example, have changed little over the past decades. Psychedelics may represent the most promising shift in mental health treatment since the 1980s,” said Bzdok.

He added that, as researchers in this emerging field still face logistical hurdles, the results provide a yardstick against which future studies can be measured and may help move the needle toward loosening strict regulations.

About the study

“An international mega-analysis of psychedelic drug effects on brain circuit function” by Manesh Girn and Danilo Bzdok et al., was published in Nature Medicine.