Observational · 2025
What adverse events are reported for psychedelics and MDMA in a global safety database
- Original title
- Adverse events associated with classic psychedelics and MDMA: a real-world population-based study using the WHO pharmacovigilance database (VigiBase).
- Authors
- Syed OA, Nestor SM, Husain MI, et al.
- Journal
- Psychiatry research, 2025
- Molecules
- MDMA, LSD, Psilocybin, DMT, Mescaline
- Conditions
- Substance use disorder, Other
- Evidence grade
- Low
- Source
- Read the original paper
The question
What kinds of side effects and harms do people report to a global drug safety database after using classic psychedelics or MDMA?
What they did
Researchers searched VigiBase, the World Health Organization’s global database of voluntarily reported adverse drug events, for reports naming classic psychedelics or MDMA. Reports came from both clinical and recreational settings around the world. They compared how often certain events were reported for these drugs versus acetaminophen (paracetamol) as a low-risk comparison, and oxycodone, an opioid, as a high-risk comparison.
What they found
Most reports involved MDMA (1,573) and LSD (394), with far fewer for psilocybin (56), DMT (18) and mescaline (15). The most common events reported were psychiatric, especially substance abuse and dependence. Overdose made up 1.1 to 1.7 percent of all adverse events, and pregnancy-related and congenital problems were rare. Compared with acetaminophen, LSD and MDMA had much higher reporting odds for alcohol abuse (LSD: 45.7 times; MDMA: 19.2 times), substance use disorder (LSD: 71.1; MDMA: 129.9) and substance dependence (LSD: 215.1; MDMA: 76.8); these figures were also higher than for oxycodone.
The fine print
Spontaneous reporting databases capture only events someone chose to report, so numbers reflect reporting patterns, not how often harms actually occur. Many people use more than one substance at a time, so an event cannot be pinned on a single drug, and fear of disclosing illegal drug use likely reduced reporting. Psilocybin, DMT and mescaline had very few reports, so their results are especially uncertain. This summary is based on the abstract only.
What it means
In real-world reports, the most frequently flagged problems with psychedelics and MDMA were psychiatric, particularly misuse and dependence, which is a different picture from tightly controlled clinical trials, though the data cannot show that the drugs caused these outcomes.
Evidence grade: Low. An exploratory analysis of voluntary, self-selected adverse event reports, which cannot show cause and effect or give true rates of harm.
This summary is based on the study’s published abstract.