The active compounds that produce the euphoric effects felt after ingesting magic mushrooms are known as Psilocybin and Psilocin. When eaten Psilocybin is oxidized into a chemical called psilocin. Psilocin is then absorbed into the blood stream where it is taken to the brain. Psilocin has a chemical structure very similar to the endogenous neurotransmitter serotonin. Neurotransmitters are chemicals that neurons use to communicate with each other. Varying levels of serotonin will affect sleep, appetite, sensory perception, temperature regulation, pain suppression and mood.
Serotonin is absorbed by neurons at receptor sites known as the 5-HT receptors. There are various types of 5-HT receptors, but Psilocin is taken up by the 5-HT2 receptor site. After the Psilocin molecules bind with the 5-HT2 receptor sites, little is known about what happens. Psilocin is considered a serotonin antagonist and may have reuptake inhibitory effects, similar to SSRI (selective serotonin reuptake inhibitor) drugs, although it differs from SSRI's in a key way. SSRI's often also engage the dopamine system, which gives them addictive potential, while Psilocybin and other Psychedelic drugs like LSD, DMT, and Mescaline have extremely low addictive potential.
There is still not enough data to explain pharmacologically exactly the effect of the active ingredients in psychedelic fungi. What we do know is that psilocin is NOT physically harmful to the body or brain. Psychological conditions can be triggered from the stress produced by a very profound experience, however if an individual is predisposed to a psychological condition it can be triggered by any kind of stress or trauma. No physical harm is done by psilocin even in extremely high dosages.