Researchers Reveal Surge in Cannabis Usage over Past 50 Years

pharmacy

A very large study from the Addiction and Mental Health Group at the University of Bath has found how cannabis across the world has changed over time finds increased strength putting consumers at greater risk of harm.

The team behind the study, arranged data from over 80,000 cannabis samples tested in the past 50 years from street samples collected in the USA, UK, Netherlands, France, Denmark, Italy and New Zealand.

According to the findings published in the journal Addiction and the research was funded by the Society for the Study of Addiction.

The researchers investigated how concentrations of traditional herbal cannabis THC (the intoxicating component of cannabis responsible for giving users a ‘high’) had changed over time in different types of cannabis.

In herbal cannabis, they found that THC concentrations increased by 14 per cent from 1970 to 2017. This was primarily due to a rising market share of stronger varieties such as sinsemilla relative to traditional herbal cannabis which contains seeds and less THC.

The team have earlier found consistent evidence that frequent use of cannabis with higher levels of THC carries an increased risk of problems such as addiction and psychotic disorders.

Dr Tom Freeman from the university said that as the strength of cannabis increases, so too has the number of people entering treatment for cannabis use problems. He also added that many Europeans are now entering drug treatment because of cannabis than heroin or cocaine.

The researchers also looked at concentrations of cannabidiol, which is not intoxicating but may have potential medical uses such as helping people to quit cannabis. In contrast to THC, they found no evidence for changes in CBD in cannabis over time.

Study co-author Sam Craft also explained that cannabis is often seen as a safer type of cannabis, but their findings shows that it is now stronger than herbal cannabis.

Craft added that traditionally, cannabis resin contained much lower amounts of THC with equal quantities of CBD, however CBD concentrations have remained stable as THC has risen substantially, meaning it is now much more harmful than it was many years ago.

According to their research, cannabis is the most widely used illicit drug in the world but has recently been legalized in Canada, Uruguay and several states in the USA. The findings of this new study have particular relevance in light of growing demands to legalize cannabis in an attempt to make it safer.

The researchers argue that increases in cannabis strength highlight the need to implement wider strategies for harm reduction similar to those used for alcohol—such as standard units and public guidelines on safer consumption limits.

Dr Tom Freeman added, “As the strength of cannabis has risen, consumers are faced with limited information to help them monitor their intake and guide decisions about relative benefits and risks. The introduction of a standard unit system for cannabis—similar to standard alcohol units—could help people to limit their consumption and use it more safely”.