Psilocybin, the main active compound in magic mushrooms, is a 5-HT receptor agonist in the psychedelics or serotonergic hallucinogen class. Psychedelic effects occur due to stimulating serotonin synapses in the reward centre, mainly at 5-HT_2A receptors, but also at 5-HT_1A and 5-HT_2C receptors. Sensory effects can include hallucinations, and heightened reaction to external stimulation and increased self-awareness and introspection.¹

Psilocybin consumed as magic mushrooms is considered relatively safe. An international survey found that 19 out of 9,233 of users or 0.2% had sought emergency treatment, with a per-event risk estimate of 0.06%. The most common symptoms were anxiety/panic and paranoia/suspiciousness, with normality returning within 24 hours for all but one respondent. Having a poor ‘mindset’, using the drug in a poor ‘setting’, or mixing substances were given as the main reasons for incidents.¹⁵

Psilocybin and other psychedelics may exert anti-depressant activity due to increasing glutamate release and by acting at the 5-HT_2A receptor, but the specific mechanism and the effect of different psychedelic drugs is still not agreed. One proposal is that antidepressive activity may actually be independent of psychedelic activity. It is also possible that the neuronal system changes its response or ‘wiring’ to such stimulation – a form of adaptive ‘neuroplasticity’.¹