Cannabis is increasingly powerful: what consequences does it have on the health of young people?

Marijuana (Cannabis sativa) is a plant native to Central Asia. Although it is often considered a single drug, it could rather be said that there are many, since this plant species is made up of multiple cannabinoids with diverse effects on the body. Two of them stand out from the rest: delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD).

In a simplified way, it could be said that CBD and THC act in opposite ways.

CBD is a “relaxing” compound and is considered to have few adverse effects. In addition, researchers are investigating its possible therapeutic uses for the treatment of cannabis withdrawal, anxiety or psychotic symptoms.

THC, the psychoactive component, produces the classic “high”, laughter and euphoria, but also anxiety or psychotic symptoms. It is, therefore, the main suspect for the consequences of cannabis for mental health in the medium and long term.

Typically, the marijuana plant and the resins – hashish – contain both compounds (THC and CBD). This makes the consumer experience the interaction between the two, added to that of many other less relevant cannabinoids.

In fact, evidence suggests that the presence of CBD in cannabis helps soften the psychoactive effects of THC. The more THC, the greater the risk of intense psychoactive effects and adverse mental health consequences; while the more CBD, the greater the cushioning of these effects.

What is high potency cannabis?

High potency cannabis is called those variants with a concentration equal to or greater than 10% THC. These varieties are achieved with artificial selection techniques, through hybridization, and with variants such as the so-called “sinsemilla” (unfertilized female plant). The result is a cannabis with THC concentrations much higher than those found in wild marijuana, which is around 0.5%.

The increase in THC is a clear trend in recent years: the amount of this compound in marijuana consumed by the general population in Western countries has been increasing by 0.29% annually since the 1970s.

Although it may not seem like much, this means that in the samples seized then, the preparations from the dried flower (what we commonly know as “marijuana”) contained 0.5-2% THC and 0.5% CBD. In the case of hashish, which is a resin produced by the plant and contains high amounts of cannabinoids, the samples had 5-10% THC and 2-6% CBD.

If you look closely at the percentages, this meant that, in the 70s, the amount of both cannabinoids was more or less balanced in both marijuana and hashish. That is, they had a THC/CBD ratio = approximately 1:1.

Currently, however, marijuana samples have increased their THC concentration to 10-14% on average, and hashish samples to around 30%. It is possible to find hashish variants even with 50% THC. However, this artificial selection process has not increased the amount of CBD, which has remained stable at low levels.

This implies that THC and CBD are no longer balanced, and that not only has the THC concentration increased, but the THC/CBD ratio has multiplied significantly. Now up to 20 times more THC than CBD is found in marijuana or hashish (20:1 ratio).

What are the dangers of high potency cannabis?

Given the higher concentrations of THC and its disproportionality compared to CBD, high-potency cannabis produces more intense psychoactive effects. Does it also pose greater risks to mental health?

Indeed, its consumption has been associated with a greater risk of mental problems and, in particular, psychotic symptoms. So much so that it is estimated that 12.2% of the first psychotic episodes diagnosed in large cities could be avoided if this cannabis were no longer available. In some cities like Amsterdam, half of the cases could be avoided.

Greater risk for the youngest

These data are worrying if we take into account that young people are one of the most vulnerable populations to the effects of cannabis on mental health.

In some countries, adolescents start using it around the age of 15. Such an early onset and, above all, the transition to frequent use during adolescence poses a significant risk of experiencing psychotic symptoms that may not have occurred. The widespread use of cannabis with high levels of THC constitutes an added risk for this vulnerable population.

This occurs in a context in which young people are unaware of the amount of THC they consume, whether they purchase products on the legal or illegal market.

In fact, imprecise categories are used. For example, it is common to consider that the variant cannabis indica is the most relaxing (since it would contain more CBD), while the Cannabis sativa It would be the most psychoactive (it would contain more THC). These strategies can offer a false sense of control to the consumer, when there is no difference at the botanical level in THC concentrations between these subspecies.

Lack of information and prevention

First of all, it is worth remembering that cannabis is not harmless and that it causes damage to physical and mental health. In addition, it is necessary to inform the specific risks that THC may have for the mental health of young people. The consumption of high potency cannabis, with or without the user's knowledge, and products with high THC content can increase symptoms and first psychotic episodes.

Secondly, legal suppliers of THC products should be required to include objective information on the amount of this cannabinoid, in milligrams, as well as the THC/CBD ratio. This would at least allow for the informed use and application of preventive harm reduction strategies.