Cannabis and neurogenesis: what's the connection?

Contrary to popular belief, scientific research continues to show that the Cannabis does not kill brain cells. Recent studies shed new light on our understanding of the subject and suggest that cannabis may increase the number of cells in our brain, a process known as neurogenesis.

What is neurogenesis?

For a long time, it was believed that brain cells stopped increasing in number after a certain age. The latest studies show that the brain continues to produce new neurons in adulthood, particularly in the hippocampus—a region of the brain that plays a major role in memory, learning, and spatial orientation—at a rate of about 5,000 new cells per day.

This process of forming new neurons, known as neurogenesis, is believed to improve brain functions such as learning and memory. Furthermore, numerous studies have linked anxiety and depression to a decline in neurogenesis.

Although neurogenesis is an ongoing process, its rate decreases with age. Regular use of opioids, alcohol, nicotine, or cocaine can also inhibit the neurogenesis process.

The link between cannabis and neurogenesis

Scientific research has found that our endocannabinoid system played a major role in neurogenesis, facilitating it throughout life, from embryonic development to adulthood.

Numerous studies show that cannabis can be used to treat symptoms associated with brain aging and a decline in neurogenesis, including:

• a study published by the Royal Society Publishing on the effects of cannabis on neural activity, particularly degenerative disorders
• the role of CB1 cannabinoid receptors in neurogenesis

Researchers studied the effects of cannabinoids on neurogenesis by using synthetic versions of the THC, the most common cannabinoid in medical cannabis. In particular, a a study conducted in 2005 by the Canadian researcher Dr. Xia Zhang found that synthetic THC—a version 100 times more potent than natural THC—not only promoted neurogenesis in animal models but also appeared to reduce symptoms of anxiety and depression, confirming the link between neurogenesis and mood disorders.

The cannabidiol (CBD) has also shown strong ability to increase neurogenesis.

«Most drug abuse inhibits neurogenesis. Only marijuana promotes neurogenesis,» according to Dr. Xia Zhang.

Interestingly, the cannabinoids naturally produced by the body (endocannabinoids) appear to have the opposite effect on brain cell formation, particularly anandamide, which could inhibit neurogenesis in adults. Experts believe this may be due to the way endocannabinoids and phytocannabinoids interact with cannabinoid receptors.

Although these studies highlight the role of synthetic THC in neurogenesis, further research using natural THC is needed to confirm the role of cannabis in neurogenesis.