David Shukman of the BBC claims that “The weed so familiar to many of my generation was characterised by a relatively balanced amount of THC and CBD” when compared to today’s hybrid strains. This is true only of traditional hashish from regions such as Afghanistan, Morocco, Lebanon and Nepal. Old-fashioned cannabis resin, which is made from landraces that have been selected for resin production and had little selection for potency, does often exhibit a roughly balanced 1:1 THC:CBD ratio. But even back in the ’60s and ’70s, during an era in which we are told cannabis was a more innocent and far gentler plant, there was plenty of imported cannabis in which CBD was often entirely absent and THC levels could be very high. Typically, this took the form either of refined cannabis oil or—more usually—of high quality ‘ganja’, meaning cured unseeded or lightly seeded flowering tops from the tropics and subtropics.
Unlike hashish landraces, the strains of cannabis that have been grown for centuries in the tropics and sub-tropics to produce ganja most often have little or no CBD and can even exhibit levels of THC comparable to those of so-called ‘skunk’. This applies, for example, to Thai, South Indian and traditional Colombian varieties. Their informal brands back in the hippie heyday were the likes of ‘Thai Stick’, ‘Kerala’, and ‘Colombian Gold’.
For skeptical readers there are some figures to back up what many older smokers know to be true from personal experience. In 1975 and 1976 the Laboratory of the Government Chemist reported Thai with as much as 17% THC—and that was after the bud had spent months on boats reaching England. THC levels such as this are far from unusual in Southeast Asia. In the ganja growing heartlands along the Mekong River generations of cultivators have provided a continuous selective pressure for high potency. A key part of the underground cannabis economy in Thailand is formed by breeders who specialise in producing high quality seed, which is then supplied to farmers when they are commissioned by well-connected patrons to raise a field or two. The best of any season’s harvest comes from such fields. Similarly, in the Imphal Valley of Manipur, all farmers and personal growers know to keep seeds from good (i.e., potent) batches of ganja for sowing the following season.
Clearly the selective pressure in traditional ganja growing is less intensive than that of the so-called ‘clone’ method for breeding skunk, in which selected ‘mother plants’ can be kept indefinitely under 24-hour light regimes. However, the cumulative effect over generations of traditional ganja farming can result in very strong cannabis that’s often devoid of CBD. Analysis of samples from tropical India indicates that CBD is typically absent—even in some of the milder Bengali strains. This was the case in the ’60s and remains so today. Regarding THC levels, further evidence that the potency of modern hybrids is far from unprecedented comes, once again, from British seizures. In the words of the Home Office, as recorded in Hansard:
The latest data from the Forensic Science Service Ltd (FSS) show that the average tetrahydrocannabinol (THC) content of mature flowering tops from plants, otherwise known as sinsemilla, seized and submitted to the FSS from the 1 January 2008 to the present day was 14.0%. By comparison, during the same period, the average THC content of traditional imported cannabis and cannabis resin was 12.5% and 5.5% respectively.
On average, skunk (the FSS called it ‘sinsemilla’) showed only 1.5% more THC than ganja. So much for many times more potent. Only in hashish would this have been offset by a similar quantity of CBD.
In fairness, the BBC’s reporting on cannabis does seem to be improving. But—even if unwittingly—Aunty is still feeding the skunk hysteria.
Looking again at the LGC data I see that in ’78 a sample of Indian cannabis resin showed 26% THC—this resin is very likely to have been prepared from tropical ganja plants rather than northern, Himalayan charas landraces. Customs bagged a 16% THC batch of Moroccan resin in ’75, and a shipment of Pakistani resin with the same strength in ’78. And then there are the concentrated extracts—‘hash oils’—with Indian, Kenyan and Pakistani samples all hitting around 40% THC. Simple extracts of this potency need to be made from starter material with a high cannabinoid content. The most potent was 48% THC oil from India seized in 1975.
That noted, the LGC does make the important point that “Cannabis resins normally had higher THC contents than most herbal material…”. Typically, the ‘herbal cannabis’ reaching UK shores during this era was of fairly low potency—mid to low single figures THC—either because it was from poor stock, or had degraded en route. This does, to be fair, support the kind of line Shukman is taking, though not the current media focus on CBD.
Ganja seldom contains CBD in any relevant quantity. Outside Southeast Asia, some of the best bud to reach Britain in the ’70s appears to have been coming from Rhodesia—now Zimbabwe—with a sample hitting 12%. Nigerian and South Indian ganja seizures were milder, at 7.4% and 7.8%—less potent, but still entirely without CBD.
Should Thai cannabis be seen as exceptional? Perhaps for this era in the UK it should, though both the quantity of samples available from seizures and ample anecdotal evidence suggest there was plenty of it about in the country, in addition to the stronger resins and concentrated oils. The LGC points out the unique appearance of the “Thai Stick” brand: “Green or brown sticks of several seedless tops tied around bamboo with a number of sticks compressed into a slab.” I’m sure there are readers who recognise this, either from having seen the real thing back in the day in the UK, or on their travels.
The LGC figures suggest that the potency of Thai seizures peaked in the early to mid ’70s, and then began to decline after the Vietnam War and the Fall of Saigon. It’s not clear whether this sample is indicative of changes at the source in Isan, Northeast Thailand. But as the authors state, in ’75 and ’76 “by far the highest quality cannabis originated in South East Asia (exclusively in the form of “Thai sticks”) and this was reflected in its street price, at least in the United Kingdom, over the same period. However, the 1978 seizures which originated in Thailand, while still prepared in the form of sticks, showed a dramatic decrease in THC level compared with previous years. A careful study of the physical appearance of seizures of Thai origin for the three years revealed an increasing seed content in the cannabis.”
To take a contrarian line, perhaps the changes that have occurred in the UK over the last two decades are about catching up to highs the market, and its consumers, had already reached in 1975.