One, five, or ten milligrams? Is there a standard ‘dose’ for THC (the main psychoactive chemical in cannabis)? No, but addiction experts think there should be.
In collaboration with scientists from King’s College London, UCL and the Australian Catholic University in Melbourne, researchers from the Addiction and Mental Health Group at the University of Bath suggest that standard units for grading the potency of cannabis – similar to those already used for alcohol – would benefit the mental health of users.
In 2018, the research team showed how concentrations of THC in cannabis doubled across Europe in the past decade. Now, according to a paper in the journal Addiction, researchers suggest a standard THC unit should be set at 5mg – a dose typically low enough to induce intoxication but not psychosis.
"Where the unit system for alcohol has helped consumers to better manage their alcohol intake, so too do we think this could have important implications for cannabis users. This should clear guidance about the dose of THC people are consuming,” says Dr. Tom Freeman, lead author of the study from the University of Bath.
In a separate study published in Psychological Medicine, researchers examined the relationship between using cannabis products and key health outcomes. In the study, over 55,000 people across 175 countries were asked survey questions about the types of cannabis products they used, as well as their mental health status and severity of cannabis dependence.
Freeman and his colleagues found that people used a variety of products (i.e., herbal, sinsemilla, hashish, and/or concentrates) and that the type of product was strongly related to certain mental health outcomes. Relative to low potency herbal cannabis users, those who used products with higher THC concentrations (e.g., hashish and/or sinsemilla) had a greater risk of cannabis dependence.
"Our findings add to a growing body of evidence that suggests the health effects of cannabis are dose-related," said lead author of the Psychological Medicine study Dr. Sam Craft from King's College London. “These risks though might be modifiable and we believe that the introduction of a unit system would help both users and healthcare professionals by providing clearer information on the types of cannabis products they consume and their strength.”
"Of course, the safest level of use for cannabis is 'no use'. Yet, we know that many people across the world regularly consume cannabis so we need to consider how we can better support them in making informed choices and to minimize potential health risks such as addiction or psychosis,” says Freeman.