“Opium smoking has been mostly replaced by i.v. injection of morphine and heroin and we see cocaine sniffing rather than chewing of coca leaves. Cannabis use – be it of marijuana, hashish or bhang – differs.
Any cannabis cognoscente will insist that the crude material is ‘much better’ than pure Δ9 – tetrahydrocannabinol (THC), the only major psychoactive constituent of cannabis (Mechoulam et al., 1970).
Indeed, although pure THC is available as a drug (named Dronabinol) it is apparently not used illicitly.
The pharmacological/biochemical basis for this difference is not clear and is presumably due to several factors. A major reason seems to be the pharmacokinetic difference between cannabis smoking and the oral administration of THC.
On smoking, the cannabis effects are noted almost immediately, while a 1.5 – 2 hour delay is observed on oral administration.
A further factor may be conditioning to the smell, although there are no published data along these lines. A further factor may be the presence of the terpenoid CB2 agonist beta-caryophyllene in cannabis (Gertsch et al., 2008).
CB2 agonists are well known to cause numerous effects (mostly of a protective nature) which may counteract some of the effects of THC (Pacher & Mechoulam, 2011).”
http://www.ncbi.nlm.nih.gov/pubmed/24024867
