Consumers seeking higher highs have reportedly driven cannabis producers to cultivate strains with the highest THC levels in history. New research suggests that the negative effects of cannabis are experienced more by those who use higher levels of THC. Researchers are also now questioning whether THC is really the cannabinoid responsible for the good feelings we associate with being high. With emerging data making high-THC cannabis seem less appealing, why are levels of the chemical rising in retail marijuana?

More THC, More Problems

With rising concentrations of THC in cannabis flower and extracts, more THC-related health issues are coming to the forefront.

In a new study published in the journal The Lancet Psychiatry, researchers found that THC potency has more than doubled in the past decade. Cases of psychosis associated with cannabis use—occurrences that used to be incredibly rare—have also increased in recent years.

The study reviewed 20 previous studies involving nearly 200,000 participants. It found that cannabis users who leaned toward products with higher THC potency were more likely to experience symptoms of psychosis and cannabis use disorder than those who used lower potency products.

Psychosis is characterized by perceptual distortions that make it difficult for a person to recognize the difference between reality and fantasy. Those suffering from psychosis might experience visual or aural hallucinations or become delusional.

While cannabis isn’t known to cause psychosis, the two have been associated because the emotionally charged experience of reaching high levels of cannabis intoxication can act as a triggering incident for a psychotic break. With an increase in access to cannabis and an increase in THC potency, more young people are experiencing psychotic episodes that were triggered by cannabis.

“One of the highest quality studies included in our publication found that use of high potency cannabis, compared to low potency cannabis, was linked to a four-fold increased risk of addiction,” study coauthor Tom Freeman at the University of Bath in the United Kingdom told CNN.

Cannabis use disorder is not typically marked by physical dependence. Beyond cravings for marijuana and an increased tolerance to the drug, symptoms revolve around persistent use in the face of social challenges against the drug. Withdrawal symptoms are mild and limited to feelings of discomfort, sleeplessness, irritability and depression.

Nevertheless, cases of the disorder are reportedly rising, and Freeman believes it’s related to the rising THC levels. The silver lining is that researchers believe users can scale back the potency of the cannabis that they consume to ward off the possibility of suffering from these adverse health effects.

Co-author Kat Petrilli told Insider that there was no way to define what a high or low level of potency is, because the various studies had different definitions. The review merely compared the higher end of the spectrum to the lower end. Most studies designated doses around 5mg as low.

How High Can You Get?

The Hebrew University of Jerusalem announced in May that it had developed a method to increase the concentration of THC in cannabis plants. Researchers manipulated a neutralized plant virus so that it expressed genes that influence the production of active cannabinoids in the cannabis plant. They reportedly engineered a pot plant that had been made to produce 17 percent higher levels of THC, 25 percent higher levels of the cannabinoid CBG (cannabigerol) and 20 to 30 percent higher levels of terpenes.

The news excited many, because it has become commonly accepted wisdom that if one is good, then two is better, and higher THC levels mean “stronger” cannabis. That belief has driven cannabis consumers to take a simple approach to shopping for flower, and THC has become the standard for judging cannabis potency as a result. Now retailers consistently charge more for higher THC levels and refer to strains with the highest levels as “top shelf.”

But research has shown that THC levels might not even correlate to level of intoxication anyway. A 2020 study from the University of Colorado Boulder found that cannabis extract users with higher levels of THC in their blood reported the same levels of intoxication as those who smoked flower and had lower levels of THC and tested similarly in measures of balance and cognitive impairment.

“Surprisingly, we found that potency did not track with intoxication levels,” said lead author Cinnamon Bidwell, an assistant professor in the Institute of Cognitive Science. “While we saw striking differences in blood levels between the two groups, they were similarly impaired.”

Next Shift

Which raises the question: Why are we struggling for higher THC levels at all? It would be easy to blame the producers and manufacturers of cannabis, but they are only responding to market pressures. Freeman calls for more public education on the risks of using high THC products.

“Our findings suggest that people who use cannabis could reduce their risk of harm by using lower potency products,” said Freeman in a press release. “In places where cannabis is legally sold, providing consumers with accurate information on product content and access to lower potency products could help people to use cannabis more safely.”

Policymakers have suggested creating THC limits for cannabis producers, but that could lead to unnecessary burdens for small producers who are unable to determine potency until very late in the growth cycle. A better move might be to encourage a paradigm shift at the consumer level so that users understand that THC concentration isn’t the most important aspect of determining cannabis potency.