Psilosybin mushrooms are very edible and are SAFE to eat.
Tripping, on the other hand, can occasionally impact your mental health.
There are no known long term physical effects from ingestion of mushrooms containing psilocybin and psilocin.
As for long term mental effects, this is a subject for debate and has no clear cut answer. Tripping can be a profound experience. And far more often than not, the experience is a very good one.
Long term mental effects from extended high dosages are quite seldom, but they may include some cognitive impairment and HPPD (Hallucinogen Persisting Perceptual Disorder) and possibly some emotional liability due to effects on the Serotonin system. Usually temporary, these fade with cessation of use over a period of a few months.
Also, people with dormant mental illness may bring their illness to the surface prematurely by tripping. Mushrooms do not cause mental illness, but they can plausibly draw one to the surface. Trip on a safe setting and eat small doses until you know your tollerance.
Keep in mind that psychedelic mushrooms are non-habit-forming and that the desire to use them can actually decreases with use. They are most often self-regulating. Also, you build an almost immediate tolerance to them after ingestion, preventing you from experiencing their full effects more often then every 4-7 days at least, unless you increase your dose. Many think it can take months without tripping before you can feel the full effects again.
Over years of occasional use, the average user notices no apparent change in his/her physical or mental condition that would be considered detrimental.