Journal of affective disorders
April 1, 2023
Otto Simonsson, Peter S Hendricks, Richard Chambers et al.
124 citations
Using nationally representative US adult data (N = 2822), most people who have used classic psychedelics (59.1%) never had a challenging, difficult, or distressing experience. However, 8.9% reported functional impairment lasting more than one day from such an experience, and 2.6% sought medical, psychiatric, or psychological help afterward. Co-use of lithium or other mood stabilizers, and certain set and setting factors—including no preparation, disagreeable physical environment, negative mindset, no psychological support, a dose perceived as too large, and a major life event prior—were associated with greater difficulty. Negative mindset, no psychological support, and a major life event prior were also linked to overall risk of harm.
Scientific Reports
July 13, 2021
Otto Simonsson, Walter Osika, Robin Carhart‐Harris et al.
54 citations
Lifetime use of classic psychedelics is associated with lower odds of heart disease and diabetes. Analyzing data from the National Survey on Drug Use and Health (2005–2014), people who had ever tried a classic psychedelic had 23% lower odds of past-year heart disease and 12% lower odds of past-year diabetes. The associations persisted after adjusting for other factors. The authors suggest classic psychedelic use might benefit cardiometabolic health but call for more research on causal pathways.
JAMA Psychiatry
March 13, 2024
Otto Simonsson, Miriam A. Mosing, Walter Osika et al.
41 citations
Among 16,255 Swedish adolescents, 541 reported past psychedelic use, and 99% of those also used other drugs. After adjusting for other drug use, psychedelic use was associated with fewer psychotic symptoms. However, the link between psychedelic use and manic symptoms depended on genetic vulnerability: adolescents with higher genetic risk for schizophrenia or bipolar I disorder showed more manic symptoms after psychedelic use. The authors urge caution due to study limitations.
Hypertension
March 8, 2021
Otto Simonsson, Peter S. Hendricks, Robin Carhart‐Harris et al.
36 citations
Adults who had used a classic psychedelic at least once in their lifetime had 14% lower odds of hypertension in the past year, after adjusting for confounders. The association was strongest for tryptamine psychedelics (DMT, ayahuasca, psilocybin), which were linked to 20% lower odds of hypertension. No significant association was found for LSD or mescaline. The authors note these findings are correlational and call for randomized controlled trials to test causal effects.
Psychopharmacology
July 1, 2025
Otto Simonsson, Simon B Goldberg, Richard Chambers et al.
33 citations
In a US-representative sample of 2,822 adults, lifetime naturalistic psychedelic use was associated with more unusual visual experiences but not with psychotic symptoms in the past two weeks. Among those who had used psychedelics, 1.3% reported a diagnosis of hallucinogen persisting perception disorder. An interaction emerged: individuals with a family history of psychotic or bipolar disorders who used psychedelics reported more psychotic symptoms, while those without such a family history reported fewer. The findings suggest that family history may modify the association between psychedelic use and psychotic symptoms.
Therapeutic advances in psychopharmacology
January 1, 2022
Otto Simonsson, Peter S Hendricks, Richard Chambers et al.
26 citations
In a US-representative sample of 2822 adults, lifetime use of classic psychedelics was linked to healthier tobacco-related and diet-related behaviors. Among the 613 who had used psychedelics, greater psychological insight during their most insightful experience was associated with healthier exercise habits, a healthy body mass index, and diet improvements. Psychological insight was also tied to self-reported health behavior improvements attributed to the psychedelic experience, including alcohol-related changes. The findings suggest that psychological insight during a classic psychedelic experience may promote positive health behavior change and better physical health, especially in weight management, though causality cannot be established.
Drug and alcohol dependence
October 1, 2022
Otto Simonsson, Simon B Goldberg, Richard Chambers et al.
16 citations
Among a US-representative sample of 2,822 adults, 613 reported lifetime classic psychedelic use, and 1.5% of those users reported having a seizure while using a classic psychedelic—a rate similar to epilepsy prevalence in the general population. Nearly half of those who had a seizure were also taking antidepressants, mood stabilizers, or opioid replacement therapies at the time. Seizures were more common among respondents with a personal or family history of epilepsy. The findings suggest that classic psychedelic use may elevate seizure risk in certain people, especially those with a personal or family history of epilepsy.
Psychological medicine
April 1, 2024
Otto Simonsson, Walter Osika, Cecilia U D Stenfors et al.
15 citations
People who used psychedelics during a two-month period reported a greater increase in days of mindfulness meditation per week than those who did not. Among psychedelic users, experiencing personal insight during the most intense psychedelic session was linked to larger increases in both mindfulness and loving-kindness or compassion meditation practice. Conversely, more frequent loving-kindness or compassion meditation at the start of the study was associated with less severe feelings of death or dying during the subsequent psychedelic experience. These findings suggest a bidirectional relationship: psychedelics may boost meditation engagement, while meditation may reduce challenging psychedelic experiences.
Mindfulness
April 1, 2023
Charlotta Simonsson, Richard Chambers, Peter S Hendricks et al.
15 citations
People who have used classic psychedelics report meditating more often, specifically mindfulness meditation, but not loving-kindness or compassion meditation. Among those who had a psychedelic experience, both psychological insight and ego dissolution were linked to more frequent practice of both types of meditation. However, when both factors were considered together, only psychological insight predicted higher meditation frequency. These findings, from a survey of 2,822 U.S. adults, suggest that psychedelic experiences—especially those that produce psychological insight—may encourage regular meditation, though causality cannot be established.
International Journal of Environmental Research and Public Health
July 1, 2022
Elin Pöllänen, Walter Osika, Otto Simonsson et al.
12 citations
People who have used classic psychedelics tend to report less speciesism and more solidarity with animals, though no link was found with their desire to help animals. Among those who used psychedelics, stronger ego dissolution during their most intense experience was associated with less speciesism, more animal solidarity, and a greater desire to help animals. These associations come from a large US-representative sample of 2,822 adults. The authors caution that the findings do not demonstrate causality and call for longitudinal studies to explore whether psychedelic use directly influences human–animal relations.
Journal of affective disorders
July 9, 2025
Otto Simonsson, Peter S Hendricks, Caroline M Swords et al.
8 citations
In a large observational study of US adults aged 18–50, naturalistic psychedelic use was modestly linked to increased depressive symptoms over time. Among 12,345 participants followed longitudinally, 505 reported psychedelic use. Those who used psychedelics in a 'risk context'—such as a negative mindset or lack of psychological support—showed a moderate increase in depressive symptoms compared to non-users and to users without such risks. This association was explained by more challenging psychedelic experiences in that context. The findings indicate that psychedelic use outside controlled therapeutic settings may not be generally beneficial and could worsen depressive symptoms under certain conditions.
Frontiers in psychology
January 1, 2023
Otto Simonsson, Cecilia U D Stenfors, Simon B Goldberg et al.
4 citations
Mindfulness meditation and psychedelic use are both associated with positive impacts on leadership, though through different mechanisms. In a representative sample of 3,150 managers in the US and UK, more lifetime hours of mindfulness meditation and greater psychological insight during the most intense psychedelic experience each independently predicted a positive leadership impact (odds ratios 2.33 and 3.49, respectively). Both practices shared subthemes such as improved focus, creativity, patience, empathy, and compassion. Unique to mindfulness were better sleep, stress reduction, and calming effects; unique to psychedelics were greater self-understanding, less hierarchical attitudes, and positive interpersonal changes. The cross-sectional design precludes causal conclusions, but the findings suggest complementary benefits for leadership development.
Research square
May 19, 2026
Sunjuri Sun, Claudia Hanson, Peter S Hendricks et al.
The evidence on child and maternal outcomes after exposure to classic psychedelics during pregnancy is very sparse and of very low certainty. A systematic review of 42 studies, mostly case reports from high-income countries, found that LSD was the most commonly reported substance. Outcomes reported included spontaneous abortions (2 studies), stillbirth (1 study), neonatal mortality (16 studies), preterm birth (17 studies), birthweight (15 studies), and congenital malformations (26 studies). No maternal deaths were reported. Because of small sample sizes and varied study designs, no meta-analysis was possible. The authors conclude that methodologically rigorous research on psychedelic use during pregnancy is urgently needed.
Journal of psychopharmacology (Oxford, England)
May 1, 2026
Otto Simonsson, Sunjuri Sun, Laura W Wesseldijk et al.
In a large twin study using the Swedish Twin Registry, people who reported using psychedelics had lower odds of having a history of migraine. Among identical twins, the twin who used psychedelics was less likely to have migraine than their co-twin who did not. The association was significant in males but not in females. These results suggest a possible link between psychedelic use and reduced migraine likelihood, with sex differences that need further study.
Journal of psychopharmacology (Oxford, England)
January 1, 2024
Otto Simonsson, Peter S Hendricks, Cecilia Ud Stenfors et al.
A longitudinal study with nearly 10,000 US and UK adults found that people who used psychedelics during a two-month period reported greater increases in unusual visual experiences compared to those who did not. The effect was strongest among first-time users. These visual experiences occurred after the acute drug effects had worn off. The findings support earlier case reports and cross-sectional studies suggesting that naturalistic psychedelic use may be linked to persistent visual phenomena, though further longitudinal research is needed to clarify cause-and-effect relationships.