Effects of LSD and Psilocybin on Heart Rate in Patients Receiving Psychedelic Treatment for Depressive and Anxiety Disorders: A Retrospective Observational Study
Morgan C H Cheng, Tatiana Aboulafia Brakha, Albert Buchard, Raya Boyanova Anastasova, Léa Girani, Anna Breitenmoser, Sylvie Alaux, Cédric Mabilais, Caroline Amberger, Federico Seragnoli, Leonice Furtado, Gabriel Thorens, Daniele Zullino, Louise Penzenstadler
Psychology International December 19, 2025 DOI: 10.3390/psycholint8010001 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Retrospective observational study Peer reviewed |
|---|---|
| Sample size | 30 |
| Population | Patients with treatment-resistant depression or anxiety disorders treated under compassionate use |
| Interventions | LSD Psilocybin |
| Dose | LSD 100–200 mcg, psilocybin 15–30 mg |
| Topics | Anxiety LSD Psilocybin Depression |
| Keywords | Hallucinogen Depression economics Adverse effect Observational study Heart rate variability Clinical psychology |
| Key findings | LSD and psilocybin show distinct temporal patterns of heart rate change in clinical patients, with LSD producing a delayed sustained increase and psilocybin an earlier decline, independent of anxiety. |
Abstract
Classic psychedelics such as lysergic acid diethylamide (LSD) and psilocybin induce mild cardiovascular activation in addition to their psychological effects. While these effects are well described in healthy adults, little is known about their dynamics in clinical populations undergoing psychedelic-assisted psychotherapy. This retrospective, observational, single-center study analyzed routinely collected data from 30 patients (mean age = 51.56 ± 12.19 years; 15/30 female) treated under compassionate use for treatment-resistant depression or anxiety disorders. Participants received either LSD (100–200 mcg) or psilocybin (15–30 mg) in supervised outpatient sessions. Heart rate and self-rated anxiety (VAS 0–100) were recorded at seven intervals from 30 to 300 min post-administration. Linear mixed models examined heart rate trajectories over time × substance, controlling for age and, in a second model, perceived anxiety. Linear mixed models revealed no significant main effect of time (F(6, 77.25) = 0.76, p = 0.60) or substance (F(1, 30.82) = 0.66, p = 0.42), but a significant time × substance interaction (F(6, 77.25) = 3.03, p = 0.01). LSD was associated with a delayed but sustained increase in heart rate peaking at 3–4 h, whereas psilocybin showed an earlier decline. These patterns persisted after adjustment for age and anxiety, and anxiety did not significantly modify the relationship between time and substance. No serious cardiovascular adverse events occurred. These preliminary findings suggest that LSD and psilocybin may produce distinct temporal patterns of cardiovascular activation in clinical settings. However, interpretation should be cautious due to the retrospective design, small sample size, and dose imbalance between substances.
In the evidence
This study is part of the evidence base for a synthesis in the library. Here is how each one recorded it.
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State of the evidence: LSD for anxiety No effect
LSD and psilocybin showed distinct temporal patterns of heart rate change, but anxiety did not significantly modify the relationship between time and substance.
Synthesized
Comparable studies
Other observational and cohort studies on LSD for anxiety, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psychedelics not linked to mental health problems or suicidal behavior: A population study Randomly selected United States adults | 2015 | Observational cohort | n = 135,095 |
| Long-lasting subjective effects of LSD in normal subjects Healthy participants | 2017 | Observational cohort | n = 16 |
| LYSERGIC ACID DIETHYLAMIDE (LSD-25) Patients with depressive reactions | 1952 | Observational cohort | n = 15 |
| Peri-traumatic consumption of classic psychedelics is associated with lower anxiety and post-traumatic responses 3 weeks after exposure. Adult survivors of a single large-scale terrorist attack at a festival | 2025 | Observational cohort | n = 343 |
| Real-world effectiveness and safety of psychedelic-assisted psychotherapy: Outcomes from a large-scale compassionate use cohort in Switzerland. Adults with treatment-resistant depressive and/or anxiety disorders | 2026 | Retrospective observational cohort | n = 115 |