Some users suffer from Hallucinogen persisting perception disorder although how many, and why, is unknown. Perceptual disturbances causing discomfort are rarely reported after using psylocybin, but they may be more likely if the drug is mixed with Cannabis. There have been reports of such disturbances lasting 5 years or more. Magic mushrooms have also been controversially associated with long term effects such as panic attacks, depression and paranoid delusions. On the other hand, magic mushrooms were rated as causing some of the least damage in the UK compared to other recreational drugs by experts in a study by the Independent Scientific Committee on Drugs.
Other researchers have said that the main chemical component (psilocybin) is "remarkably non-toxic to the body's organ systems", explaining that the risks are indirect: higher dosages are more likely to cause fear and may result in dangerous behavior.