Abstract
Hall and Degenhart have attempted to establish a link between cannabis use and psychotic illness. Despite increasing research into cognitive deficits, there does not appear to be any consensus on the role of cannabis in the genesis of schizophrenia; and, as Hall and Degenhart have alluded, there remains the problem of disentangling cause from consequence and coincidence.
A further complexity not yet investigated is that cannabis, unlike alcohol, is not only illicit and unstandardised, but contains many cannabinoids, several of which are psycho-active. Consequently, a number of regional variants exist. Users will confirm that there is a spectrum of potency reflecting not only the portion of active tetrahydrocannabinoids (THC), but also which cannabinoids are present.
Thirty years ago, cannabis-induced psychosis was described in the Bahamas, it was then suggested that this syndrome was related to a particular plant from Mexico [1].
There are probably several active cannabinoids and some, although not particularly intoxicating, may be more psychogenic than others. Research into this problem might be more fruitful if more attention were given to such questions as which cannabinoid, what type of psychosis and which cultural variations are involved.