How often do psychedelics trigger mania or hypomania? A review of 23 studies

The question

Can classic psychedelics or MDMA trigger mania or hypomania, and do people who use them go on to develop bipolar disorder?

What they did

Researchers searched databases and trial registries up to January 26, 2026 for human studies reporting manic or hypomanic symptoms after use of psilocybin, LSD, mescaline, DMT/ayahuasca or MDMA. They included randomized and non-randomized clinical studies, registry-based cohorts, cross-sectional surveys and longitudinal observational studies, and rated each study’s risk of bias with standard tools. Twenty-three studies met the criteria and four could be combined statistically. Mania means an abnormally elevated, energized mood; hypomania is a milder form.

What they found

Reported rates of dysphoria/euphoria, hypomania or mania ranged from 5.8% in controlled trials of psilocybin-assisted psychotherapy for major depressive disorder to 30% in naturalistic studies of people who already had bipolar disorder. When manic symptoms appeared, they were usually acute and settled on their own. Higher risk was seen in people with bipolar I disorder, a family history, polysubstance use, and unsupervised or illegal use. Pooling registry-based cohorts (7,478 people), 4% later received a bipolar disorder diagnosis (95% confidence interval 2-8%), with little sign of a signal specific to hallucinogens.

The fine print

Only four of the 23 studies could be pooled, and the underlying evidence mixes controlled trials with surveys and registry data, which cannot show cause and effect. Naturalistic studies rely on self-report and self-selected participants, and clinical trials usually screen out people with bipolar disorder, so trial rates may understate real-world risk. The authors note that long-term outcomes and repeated exposure remain insufficiently studied. This summary is based on the abstract only.

What it means

Across the available human research, psychedelics appear to carry a low but real risk of short-lived manic or hypomanic symptoms, concentrated in people with bipolar vulnerability, and the review found little evidence that they specifically drive later bipolar diagnoses.

Evidence grade: Low. A systematic review that pooled only four studies, most of the evidence coming from observational cohorts and surveys rather than randomized trials.

This summary is based on the study’s published abstract.