I recently posted a criticism of psychedelic drugs that draws on Indian and Jewish spirituality in the Philosophy and Spirituality forum and it states that psychedelic drugs can oxidize serotonin. No one has addressed it yet, so I figured I'd post it in reply to your post.
'The use of drugs depletes ojas and deranges the prana and the tejas. A typical ojas-depleting drug is marijuana; others include peyote, psychedelic mushrooms, LSD, ecstasy, cocaine, heroin, amphetamines, and ketamine. One of the most serious problems associated with these herbal and pharmaceutical drugs is their effect of
hyperstimulating the serotonin concentrations through a variety of mechanisms to create neuronal destruction from an excess of serotonin, which then becomes oxidized. In this oxidized form, the serotonin is neurotoxic.'
Gabriel Cousens.
Spiritual Nutrition (2005). From the section 'Drug Use' in chapter 25. Emphasis mine.
See the full post here:
The Damage Drugs Inflict On The Spiritual Body