In light of rapidly shifting cannabis policies in Canada, the US, and elsewhere, a group of London researchers are encouraging a discussion around reducing the harms associated with cannabis.
The researchers from King’s College London and University College London pointed to two public health trends that will need to be addressed: increases in the number of people seeking treatment for cannabis dependence and higher levels of THC in cannabis. Other issues they addressed included the relationship between cannabis use and psychosis, and cannabis's potential effects on cognition and intelligence.
The trend towards higher THC content may be due to selective breeding over the past few decades for plants that yield more THC, as well as the increased availability of high-potency strains (sinsemilla, skunk) over outdoor-grown cannabis.
The cannabis plant produces THC and CBD from the same precursor, so plants that are selected for high THC content will consequently tend to have low CBD content. This is relevant to note because the evidence suggests that CBD can counteract many of the negative side effects of THC, including anxiety, paranoia, impairment to memory and emotional processing, and psychotic symptoms.
In addition, CBD does not appear to decrease how much people enjoy smoking cannabis. This is what makes increasing CBD content of cannabis products an ideal harm reduction strategy: it could counteract some of the negative effects of THC without decreasing people’s enjoyment of the plant.
With regards to dependence, it’s estimated that one in 11 people who try cannabis will become dependent at some point in their lifetime, with more severe cannabis dependence being associated with the use of higher potency cannabis. Higher potency cannabis has also been associated with a greater risk and earlier onset of psychosis. Both of these points suggest that addressing the potency issues and ensuring adequate CBD content could be effective harm reduction strategies.
The researchers also discussed possible impairments to memory and cognition, but the existing research is far from conclusive on these points. While some studies have reported correlations between cannabis use and decreased rates of high school completion or a several-point drop in IQ, follow-up studies that controlled for confounding factors have reported no such decreases. And while cognitive impairments have been found for ongoing cannabis use, those impairments are no longer present following four weeks of abstinence, suggesting they are not long-term effects.
In considering these harms, the researchers recommended several straightforward measures that would effectively target the existing harms of cannabis use: discourage the mixing of tobacco with cannabis, promote vaporizers over smoking, and ensure that cannabis products have an adequate CBD content relative to the THC content.
They also point to the need for additional research to better understand the effects of different THC concentrations. Researchers have only been including THC content in their studies since 2009, so much more research will need to be done to understand the relationship between THC levels and harmful effects. Similarly, more research is needed on different ratios of CBD and THC to better understand the protective role of CBD. This could allow us to develop a “safe” CBD to THC ratio which could be implemented as a harm reduction strategy by public health authorities, or included in legislation specifying the cannabinoid content of cannabis products.
Featured image via Ashton.