...leaves of Mitragyna speciosa, tree of Malaysia and Thailand, used as opium substitue, methods included tea, smoking and chewing. Found to supress opiate withdrawal syndrome. Chronic users said to have darkened skin. Said to have both stimulating and depressant qualities as if chewing coca leaves and smoking opium simultaneously. Large doses lead to stupor. Withdrawal said to be considerably milder than that with the opiates. Mitragynine is thus a drug with a highly unusual but never the less well-documented history of being described as both a stimulant and depressant while at the same time posessing the chemical structure one might expect of a psychedelic. The Thai narcotic book described kratom as weaker than morphine and less harmful than cocaine.