Yes, shrooms are a drug. “Shrooms” is the common name for psilocybin mushrooms, a naturally occurring psychedelic that alters perception, mood, and thought. Psilocybin is classified as a Schedule I controlled substance under federal law, placing it in the same legal category as heroin and LSD. Despite that classification, it has a notably different safety profile than most controlled substances.
What Kind of Drug Psilocybin Is
Psilocybin belongs to the class of serotonergic psychedelics, sometimes called hallucinogens or classical psychedelics. It was first isolated from Psilocybe mushrooms by chemist Albert Hofmann in 1957 and synthesized in a lab the following year. More than 200 species of mushrooms naturally produce psilocybin, with Psilocybe cubensis being the most widely known.
Once you eat psilocybin mushrooms, your body converts psilocybin into its active form, psilocin. Psilocin works by binding to serotonin receptors in the brain, particularly a receptor type involved in mood, perception, and cognition. This binding triggers a cascade of signaling inside brain cells that changes how different brain regions communicate with each other. The result is the characteristic “trip”: shifts in visual perception, altered sense of time, emotional intensity, and sometimes profound changes in how you perceive yourself and your surroundings.
How It Affects the Body
The physical effects of psilocybin are relatively mild compared to many other controlled substances. In normal doses (roughly 5 to 50 grams of fresh mushrooms, or about 0.5 to 5 grams dried), the most consistent physical changes are slight increases in heart rate and blood pressure. Studies measuring these changes found heart rate typically rises from a resting baseline of around 68 to 70 beats per minute up to about 80 to 87 beats per minute. Blood pressure follows a similar modest bump. These changes are temporary and dose-dependent, and in clinical settings they haven’t required medical intervention.
Other common physical effects include nausea, shivering, dizziness, and abdominal discomfort. Some of these symptoms may be caused by other compounds in the mushroom rather than psilocybin itself, or they may be partly psychosomatic. A trip typically lasts four to six hours, with the peak occurring around two hours after ingestion.
The psychological effects carry more risk than the physical ones. Intense anxiety, paranoia, and frightening hallucinations (a “bad trip”) are the primary dangers of uncontrolled use. In rare cases, people have reported passing out, difficulty breathing, or seizures, though the exact causes of these events aren’t fully understood. A small percentage of people, estimated at around 4.2% in one diagnostic manual, develop a condition where visual disturbances like halos, trails, or geometric patterns persist after the drug has worn off.
Toxicity and Addiction Potential
Psilocybin is a physiologically safe substance relative to most other psychoactive drugs. There is no evidence that it causes organ damage, brain cell death, or physical addiction. It does not produce withdrawal symptoms, and it lacks the reinforcing properties that drive compulsive use of drugs like opioids, nicotine, or stimulants. The primary risk is psychological, not physiological.
The estimated lethal dose of psilocybin is roughly 1,000 times larger than a typical active dose. In practical terms, a person would need to consume around 10 kilograms of fresh mushrooms (about 22 pounds) to approach a lethal amount, and vomiting would almost certainly occur long before that point. Only three deaths in the medical literature have been attributed directly to psilocybin toxicity. That therapeutic index of 1:1,000 makes it significantly harder to fatally overdose on than most commonly used drugs, legal or otherwise.
Legal Status
Under federal law, psilocybin and psilocin are both Schedule I controlled substances. Schedule I is reserved for drugs the government considers to have high abuse potential, no currently accepted medical use, and a lack of accepted safety for use under medical supervision. As of 2025, this classification remains unchanged at the federal level, and the government has actually increased production quotas for psilocybin and psilocin to support the growing number of clinical trials.
Some cities and states have moved to decriminalize psilocybin possession or create regulated therapeutic access. Oregon created a supervised psilocybin services program, and Colorado passed similar legislation. Decriminalization does not make psilocybin legal; it generally means possession is treated as a low-priority offense rather than prosecuted aggressively. Selling or manufacturing psilocybin mushrooms remains a serious federal crime everywhere in the United States.
Medical Research and FDA Status
The FDA granted psilocybin “breakthrough therapy” designation in 2018 for treatment-resistant depression and again in 2019 for major depressive disorder. This designation is meant to speed up development and review of drugs that treat serious conditions. It is not an approval. As of now, 134 clinical trials involving psilocybin have been registered, spanning more than 20 years of research and covering over 50 potential uses. None have resulted in FDA marketing approval.
Depression is the most studied application, with 39 trials focused on various forms of the condition. Other trials are exploring psilocybin for anxiety, addiction, PTSD, and end-of-life distress in terminal illness. The path to approval has been slow, and researchers have noted the field lacks a clear direction forward despite the volume of trials underway.
Drug Testing and Detection
Standard workplace drug panels (the typical 5-panel or 10-panel tests) do not screen for psilocybin or psilocin. Specialized tests can detect psilocin in urine, but the detection window is extremely narrow. Psilocin has limited stability in biological specimens and is generally only detectable for about 24 hours after use. This short window, combined with the fact that most employers don’t test for it, means psilocybin rarely shows up on drug screenings. That said, specialized labs have begun offering psilocin testing for organizations that specifically request it.