Cannabis has been used by humans for thousands of years and is one of the most popular drugs today. With effects such as feelings of joy and relaxation, it is also legal to prescribe or take in several countries.
But how does using the drug affect the mind? In three recent studies, published in The Journal of Psychopharmacology, Neuropsychopharmacology, and the International Journal of Neuropsychopharmacology, we show that it can influence a number of cognitive and psychological processes.
The United Nations Office on Drugs and Crime reported that, in 2018, approximately 192 million people worldwide aged between 15 and 64 used cannabis recreationally. Young adults are particularly keen, with 35% of people between the ages of 18 and 25 using it, while only 10% of people over the age of 26 do.
This indicates that the main users are adolescents and young adults, whose brains are still in development. They may therefore be particularly vulnerable to the effects of cannabis use on the brain in the longer term.
Tetrahydrocannabinol (THC) is the main psychoactive compound in cannabis. It acts on the brain’s “endocannabinoid system”, which are receptors which respond to the chemical components of cannabis. The cannabis receptors are densely populated in prefrontal and limbic areas in the brain, which are involved in reward and motivation. They regulate signalling of the brain chemicals dopamine, gamma-aminobutyric acid (GABA) and glutamate.
We know that dopamine is involved in motivation, reward and learning. GABA and glutamate play a part in cognitive processes, including learning and memory.
