A note on the cannabinoid content of Jamaican ganja

There has been considerable recent interest in the study of Jamaican ganja users as a potentially valuable source of information on the effects of long-term cannabis consumption. However, reported data on the cannabinoid content of Jamaican material have been limited to those of Rubin and Comitas for a small number of samples of unknown representativeness. In the present study, the cannabinoid content was determined on 36 samples purchased from various ganja dealers at two different periods, derived from crops treated differently with respect to fertilization, and representing the range of types locally considered to differ in quality or potency. The analytical results agreed well with those of Rubin and Comitas, and indicated that samples with a delta9-THC content of 4.0% or more were apt to be comparatively rare. The median value was 2.3% by weight. Some of the variation in the THC content of the samples was clearly attributable to the different seasons in which they were purchased, and some may have been due to differences in the type of fertilizer used in cultivation. Local judgement as to the potency of samples proved generally sound, although by no means infallible.