Cannabis stands out the plant kingdom. It’s the only genus known to science that produces cannabinoids. These chemicals closely mimic compounds formed deep in the human brain, and this is precisely why they are able to change a user’s state of mind. By 1974, scientists had identified over 37 cannabinoids that occur naturally in the plant. Most of these compounds occur in too small amounts to affect the human brain.
Some of them, however, are much more richly abundant in the plant, and they excite the human brain significantly. The most famous of these is delta-9-trans-tetrahydrocannabinol. This compound, more commonly known as “THC,” is the primary psychoactive compound in cannabis. Known for its ability to trigger an almost immediate state of euphoria in most, this chemical stimulates many different brain regions and can also cause short-term memory loss.
A lesser-known component of cannabis, delta-8-THC, occurs in low concentrations in the plant and is less psychoactive. Some experts believe that this chemical is a byproduct of the testing process itself. Much more significant is cannabidiol, which is the second most common cannabinoid found in marijuana.
Cannabidiol by itself cannot get you high, but ongoing research suggests that it is likely the trigger for many of the plant’s reported medicinal qualities. In fact, concentrated CBD oil has been reported by several parents of children with severe epilepsy as an effective treatment for the disease. What alarms some researchers, however, is the fact that THC levels in modern marijuana appear to be between 2 and 20 percent higher than they were in the ’60s.
The University of Mississippi runs the nation’s only long-term marijuana research facility. The school’s Potency Monitoring Project has been testing strains from all over the United States for decades. In their 2008 report, average THC levels for American cannabis were 8.52%, but the highest recording came in at around 20%. In 1978, however, the project reported an average THC level of just 1.37%. By 1988, that number had jumped to 3.59%. It’s important to note, however, that while average THC levels have risen, THC levels vary greatly from strain to strain. It’s still possible to find low-THC strains. In fact, high CBD strains such as Charlotte’s Web contain virtually no THC.
Additionally, according to the Washington Post, in their 2002 exposé on marijuana consumption habits, people today roll smaller joints than they did in the ’60s. This could, in theory, keep THC consumption on an even keel if the trend continues. However, this certainly doesn’t apply to high-THC strains such as Bruce Banner, A-Dub and Tickle-Kush which can be up to 30% THC. Many medical marijuana advocates state, however, that higher-potency marijuana means that less plant matter is required to achieve the desired effect, and these individuals further point out that pipes require less marijuana than joints.
Some experts contend that marijuana is becoming more potent over time because of the way that the crop is grown. Scientists have long known that if female Cannabis sativa plants are grown in isolation, their buds will contain higher concentrations of THC than they otherwise would. Additionally, many argue that hydroponic weed is more potent than “bush weed.” There is some merit to this claim as the amount of THC production in the plant depends on humidity, temperature and the amount of moisture received, among many other factors. Growers have substantially more control over these factors in a hydroponic setup.
Ultimately, though, cannabis is becoming more potent because demand for it has been steadily increasing. In Amsterdam, which has allowed marijuana consumption in designated areas for decades, many strains of cannabis achieve up to 30% THC. It’s the same anywhere: cannabis enthusiasts want a more potent product for their money. Crafty growers cross-breed various strains in an attempt to accommodate demand, and the result is a dizzying array of high-THC strains. Eventually, however, THC content will hit a ceiling that not even artificial selection can trump. This may leave some very heavy users of the drug looking for a new high, but casual users need not concern themselves. 30% THC is enough to leave the typical person in a comfortable haze for hours on end.