Lets preface this article with some information on The Global Drug Survey, an expansive meta-analysis of drug usage worldwide that is published yearly. Over 120,000 people participated in this study in 2017. Out of the 13 drugs/drug classes studied, Magic Mushrooms rated the safest and often rate the best value drug although in 2017 it was narrowly edged out by LSD, both members of the entheogenic or hallucinogenic category. In the data for 2017 0.4% of participants (or 4 out of 1000) reported seeking emergency after taking magic mushrooms. Comparatively this number was 13.6% for heroin, and 3.2% for amphetamines. (shown below)
5.2% reported a challenging mushroom experience had occurred at some point in their life, although an overwhelmingly vast majority said the experience was "net positive" giving them personal insight and benefit in the long run. (shown below)
While Psilocybin is one of the safest drugs, it is still a drug, which means that it inherently carries some risks. One of the biggest risks commonly associated with Psilocybin mushrooms is actually identifying the mushrooms in the wild. There are millions of species of fungi many of which look very similar to Psilocybe Cubensis, and many of which who are toxic. It is highly discouraged that anyone but an expert mycologist eat mushrooms that they find growing anywhere.
Another less prevalent risk of taking Psilocybin is increased chance of a Psychotic condition being triggered, however studies have shown this to occur only if the individual is predisposed to such a condition, and it is likely that said condition would be triggered at some point by other psychological or physical stress. Approximately 1% of the Human population is predisposed to psychotic conditions like Schizophrenia. You should not use Psilocybin if your family has a history of Schizophrenia.
For the vast majority of the population, the worst thing that can happen when taking Psilocybin is temporary discomfort. This is not to belittle the sometimes harrowing experience of a "bad trip" but to keep the long term in perspective. Studies at John Hopkins University showed that a whopping 84% of participants who had a challenging experience said that it was beneficial in the long term for both emotional development and overall well being. Furthermore 34% said that the "bad trip" was one of the top 5 most meaningful experiences of their lives, while over half said they would go through it again!
Another pertinent note about challenging experiences is that when individuals who have ingested psilocybin are admitted to emergency treatment centres doctors treat them with benzodiazepines to quickly bring back the alert, problem solving state of consciousness we remain in when sober.
In summary, Psilocybin is statistically THE safest scheduled drug. While the potential for risk does exist it is marginal compared to other drugs. The amount of human trials that have been approved by the FDA and other governing bodies that will take place at high profile universities like Harvard, Stanford, and University of Toronto is ever increasing, and highlights the fact that shrooms are not only safe, but have profound medical, therapeutic and psychological benefits.