A new longitudinal study involving more than 240,000 individuals in the United Kingdom suggests that people who used both psychedelics and cannabis during the COVID-19 pandemic experienced average improvements in symptoms of anxiety and depression over time. Unlike other groups of drug users—who tended to report persistently worse mental health—this group’s mental health scores became comparable to those of individuals who had never used illicit drugs. The findings have been published in the Journal of Psychopharmacology.
Psychedelics are a class of substances that alter perception, mood, and cognitive processes. Classic psychedelics include psilocybin (the active compound in magic mushrooms), lysergic acid diethylamide (LSD), and dimethyltryptamine (DMT). These substances are known for producing intense alterations in consciousness, including visual and auditory hallucinations, shifts in thought patterns, and changes in self-perception. Unlike more commonly used substances such as alcohol or cannabis, psychedelics are often used less frequently and in settings intended to foster introspection or emotional insight.
Research in recent years has reignited interest in the therapeutic potential of psychedelics. Clinical trials have explored their effects on conditions such as major depression, post-traumatic stress disorder, and substance use disorders. Some studies have also suggested that psychedelics may help people cope with stress or improve emotional resilience when used outside clinical settings. However, most evidence has come from small, controlled trials, while data on real-world, long-term use has remained limited.
The COVID-19 pandemic significantly disrupted daily life and mental well-being, creating a natural context in which to study how people coped with stress—including through drug use. Although overall drug consumption decreased in some cases, many individuals began using or increased their use of drugs like cannabis and psychedelics as a way of managing distress. However, most prior research focused on alcohol, tobacco, or cannabis and often grouped all other substances together, making it difficult to understand how different types of drugs might relate to mental health outcomes.
The new study, led by Maria Bălăeţ—now head of the Altered States, Evolution and Technology Laboratory (ASET LAB) at King’s College London and formerly of Imperial College London—sought to understand how specific patterns of drug use were associated with mental health symptoms before and during the pandemic. The study is part of the Great British Intelligence Test, a citizen science initiative supported by the BBC and designed to examine links between lifestyle, cognition, and health.
Participants were recruited online between December 2019 and early 2022, both before and after COVID-19 restrictions were introduced in the UK. More than 240,000 individuals completed baseline assessments, and about 68,000 provided follow-up data at three separate timepoints: December 2020, June 2021, and January 2022. The researchers used a variety of tools to track changes in mental health, including adapted items from the PHQ-9 and GAD-7 scales, which measure symptoms of depression and anxiety.
Participants were also asked about their use of a wide range of illicit substances, including cannabis, cocaine, MDMA, psilocybin, LSD, and DMT. Using a data-driven technique known as k-modes clustering, the researchers identified six distinct groups based on drug use patterns: cannabis-only users, cocaine-only users, users of both cannabis and cocaine, users of both cannabis and psychedelics, polydrug users, and users of unspecified “other” drugs. These groups were compared with drug-naive individuals and with people who had used drugs in the past but not during the pandemic.
“Back in 2023, I published a cross-sectional analysis where I compared the mental health of drug-user groups relative to drug-naive individuals during the peak of the COVID-19 pandemic, and I was surprised when I saw that, contrary to my hypothesis, the psychedelics and cannabis group had significantly poorer mental health and resilience,” Bălăeţ said.
“This made me hypothesize that perhaps we can only see improvements following psychedelic experiences if we look at the same individuals before and after, but not relative to drug-naive individuals. This would mean that psychedelics may indeed work to improve mental health, but would not make the group of users more mentally healthy than the drug naive.”
Mixed-effects models were used to track how symptoms changed over time within and between groups, adjusting for demographic and lifestyle factors such as age, sex, ethnicity, exercise, and meditation habits.
At the start of the study, nearly all individuals who reported using drugs—including psychedelics—had worse average mental health scores than people who had never used illicit substances. This pattern held across all major symptoms measured, including depression, anxiety, insomnia, and difficulty concentrating. People who increased their drug use during the pandemic also tended to see their mental health worsen over time.
However, the group of participants who used both psychedelics and cannabis showed a different trend. Although they began the study with elevated symptoms of depression and lower overall mental health scores, their average scores improved by the final follow-up in January 2022. Specifically, depression scores dropped by about a quarter of a standard deviation, anxiety scores also fell by a similar amount, and overall mental health scores improved. By the end of the study, their scores were no different from those of drug-naive individuals.
This pattern did not hold for cannabis-only users. People in that group consistently reported worse mental health across all symptoms and timepoints, with no significant improvements. Those who used both psychedelics and cannabis and decreased their usage over time reported better mental health outcomes than those who increased usage or made no change.
Interestingly, these improvements occurred despite the fact that the psychedelics and cannabis group, like other users, began with poorer mental health than the drug-naive group. This suggests that something changed for this group over time, while others stayed relatively stable or declined.
“My current paper illustrates that not only improvements in mental health are a possibility within the group of psychedelics and cannabis users, confirming my hypothesis, but also a normalization of mental health across users is a possibility, making them on par with the drug naive,” Bălăeţ told PsyPost. “I suppose this is somewhat surprising, because these results emerge from an observational study of naturalistic use, not controlled administration within a clinical setting.”
“However, I would note the key importance of the global context in the potential interpretation of results – when the mental health of the group of psychedelics and cannabis users was worse than that of drug naive group, this occurred during a period of global crisis, whereas the normalization was observed in the aftermath of the stressful period that the peak-pandemic was, during relatively calmer times. In another paper, I explore how the context where experiences with psychedelics happen may drive the experiences themselves.”
One of the main strengths of the study is its exceptionally large and diverse sample, which included over 240,000 individuals and allowed for robust statistical analyses across different drug use patterns. The longitudinal design enabled the researchers to track mental health changes over time rather than relying solely on cross-sectional data.
“Our study had a large sample of participants, which was recruited for an intelligence study, and who also consented to answering a brief drug survey at various timepoints,” Bălăeţ said. “Therefore, we can have higher confidence in the ecological validity of our results than if individuals were recruited from channels specifically endorsing drug use or psychedelics, which may be biased toward positive experiences with these substances.”
But the researchers caution against drawing firm conclusions about cause and effect. One alternative explanation for the observed improvements is regression to the mean—a statistical phenomenon where extreme scores tend to move closer to the average over time. It’s also possible that people whose mental health was already improving were more likely to use psychedelics near the time of the final survey. Without information on the exact timing or frequency of psychedelic use, it’s difficult to determine what came first.
The study also lacked data on dosage, “set and setting” (i.e., the psychological and environmental context of drug use), or the presence of co-occurring treatments like therapy or psychiatric medication.
Still, the findings suggest that psychedelics may play a distinct role in shaping mental health trajectories, particularly in times of collective stress. Unlike cannabis-only users, those who also used psychedelics reported average improvements over a two-year period, pointing to the possibility that the broader context in which these substances are used—along with their unique psychological effects—could contribute to changes in well-being.
“Importantly, though, these are group average effects, and there was notable variability within each group of drug users regardless of their substances of choice,” Bălăeţ noted.
Future research could build on these findings by examining timing, frequency, and context of use, and by exploring how psychedelics interact with cannabis and other substances. Longitudinal studies that include in-depth interviews or real-time monitoring could also help clarify whether psychedelic use during difficult life periods supports mental health in ways that differ from other forms of drug use.
“We have a lot of amazing research in the pipeline, with key study findings currently being prepared for publication,” Bălăeţ said. “I am particularly interested in the associations between naturalistic drug use, cognition, and creativity.”
The study, “Naturalistic use of psychedelics is associated with longitudinal improvements in anxiety and depression during global crisis times,” was authored by Maria Bălăeţ, William Trender, Annalaura Lerede, Peter J Hellyer, and Adam Hampshire.
