That pattern of use is pretty heavy, but any harms will be psychological, the psyche shaped by frequent excursions outside of consensual reality.
As psilocybin works via direct agonism at various 5ht sites, it does not deplete intracellular, presynaptic 5ht a la MDMA.
So why the pattern of tolerance? I believe that it isn't too well understood. Receptor-downregulation seems unlikely due to the time-course of such down-regulation and cells' ability to re-upregulate in time. I do know that one study confirmed that LSD doesn't cause depletion of 5ht or cellular damage at such sites, and this should generalize to psilocybin.
Anyone more knowledgeable here?
ebola