A new study by researchers from the University of Bath has shown that people who use stronger forms of cannabis are more likely to experience addiction and psychosis.
The potency or strength of cannabis products has gone up globally in recent decades, according to researchers. As a result, more people are now being treated for addiction and mental issues.
In this new study, researchers probed the health effects of cannabis products of different strengths. Their findings suggest that using high-potency cannabis makes a person more likely to suffer addiction. Also, people who use potent weed have a higher likelihood of experiencing a psychotic disorder – for example, schizophrenia.
“These results are important in the context of harm reduction, which aims to minimize the negative consequences associated with drug use,” said lead author Kat Petrilli.
The study was done by scientists from the University of Bath’s Addiction and Mental Health Group. It appeared in The Lancet Psychiatry.
The researchers said their findings may explain why an increasing number of people have been treated for issues related to cannabis use in recent years.
Cannabis potency and addiction
Cannabis potency is the strength or concentration of tetrahydrocannabinol (THC) in weed. THC is the main psychoactive component of cannabis – the factor behind the “high” feeling.
Evidence suggests that THC concentrations in cannabis products have been increasing in recent years. Yet, a significant number of people use cannabis regularly around the globe despite being illegal in many places.
Cannabis is the next most widely-used drug after alcohol and nicotine. In the UK (where these researchers are based), roughly one in every five persons aged 16-24 years had used the drug in the past year.
The Bath researchers found in recent, separate research that THC concentrations in cannabis products have risen considerably over time. These products have become stronger – more psychoactive – than they used to be.
As a result, more people are seeking treatment for cannabis addiction. The European Monitoring Center for Drugs and Drug Addiction has reported a 76 percent rise in the number of people entering treatment during the past decade.
In this new research, the team carried out a systematic analysis of studies on the links between different types of cannabis and their health effects. They reviewed 20 studies involving almost 120,000 subjects in all.
“Our systematic review found that people who use higher-potency cannabis could be at increased risk of addiction as well as psychosis when compared to people who use cannabis products with lower potencies,” Petrilli said.
However, the link between cannabis strength and other mental health issues, such as anxiety and depression was unclear.
Policies and guidelines for safer use needed
Cannabis use for recreational purposes is still illegal in the UK. But this is legal in some places in the United States as well as in Canada and Uruguay. Some other countries around the world, including Germany, are also looking to follow suit.
The Bath researchers noted that their findings suggest a need for public health policies and guidelines to ensure safer cannabis use.
“While the safest level of use for cannabis is of course ‘no use,’ it is important to acknowledge that a significant number of people across the world use cannabis regularly,” said Petrilli, “and to ensure they can make informed decisions that could reduce any possible harms associated with it.”
The Liberal Democrats in the UK have advocated for a legally regulated market, saying this will ensure safer use. They say such an arrangement would enable control of potency while also providing revenue for education on and treatment of problems linked to cannabis use.
Senior study author Dr. Tom Freeman said that customers should be provided with correct information on the content of cannabis products in places where they are sold legally. Access to lower-potency products in such places would also help.