Xiansi you post is so riddled with errors i don't know where to start. I'm not going to comment on the orange peel/peanut portion, i feel that was covered by some of my previous posts. Psilocin does mimic serotonin and bind to the same receptors in the brain as you stated, but it does not deplete the natural serotonin in the bran like other drugs, MDMA is a great example. So after tripping on mushrooms you don't have less serotonin.

Moving on...anti-depressants don't "mimic" serotonin at all. The most common type SSRI's are Selective serotonin reuptake inhibitors. That means they work by preventing the brains reabsorption of serotonin thus increasing its availability. Because if this it takes a while to feel the effects of ssri's, usually 4-6 weeks. It not simply a serotonin pill that makes you happy. Finally "zanax" which is spelled Xanax btw is not an anti-depressent but an anti-anxiety drug. It belongs to a group of chemicals known as Benzodiazepines. The chemical in Xanax is alprazolam just in case you wanted to know. All Benzodiazepines work by increasing the production of GABA (gamma-aminobutyric acid) which is responsible for slowing down the transmission of nerve signals to the brain giving you that relaxed feeling.

Alright this should clear some things up for the kiddies,
Shpongled