Health Effects of Cannabis on the Brain

Some people believe smoking marijuana products carries no risks. Research shows that even teens are at risk from smoking marijuana. The effects of marijuana on a person's judgment and ability to drive can lead to impaired driving. Regular users can experience poor academic performance or addiction.

How can marijuana have such an impact on someone's ability for function?

This question has been a constant concern for scientists for decades. After decades of research, they discovered the mechanism behind marijuana's effects. They also discovered a communication system within the brain and body that is important for regulating the use of marijuana. This system was called by scientists after the cannabis plant.

"Endo"--what? Understanding the science of marijuana began in the mid-1960s with the identification of THC (delta-9-tetrahydrocannabinol) as marijuana's main active ingredient. Twenty years later scientists discovered the receptors for marijuana in the brain and body. They were called cannabinoid or (CB) receptors.

Scientists then discovered the body's own natural chemicals--anandamide and 2-AG (2-arachidonoyl glycerol)--which also act on CB receptors. The endocannabinoid system (EC) is made up of these chemicals, also known as cannabinoids.

It is located in many parts of the brain and can be found in many other areas. This explains why it has so many effects on different body functions. Cannabinoids regulate how cells communicate, which is how they send, receive and process messages. Cannabinoids can act as a "dimmer switch", slowing down cell communication.

How does THC impact the EC system?

THC is absorbed quickly into the brain by those who smoke marijuana. It attaches to cannabinoid-receptors. The natural EC system can adjust to the incoming information and is highly tuned. THC, however, overwhelms the EC. It blocks the natural chemicals from performing their jobs properly, and throws off balance.

What are the short-term effects on the brain of marijuana?

Recent marijuana use in youth and adults (defined as within the last 24 hours) has an immediate effect on thinking, attention and memory.

What long-term effects does marijuana have on the brain?

Marijuana affects brain development. Brain development is affected by marijuana.

Marijuana may have a negative effect on how the brain creates connections for functions such as attention, memory and learning. More research is required to fully understand these effects.

There are many factors that influence the brain's response to marijuana use.

• The amount of tetrahydrocannabinol in marijuana (or, in other words, its concentration or strength).
• The frequency it is used.
• The age at which the first use was made.
• If other substances, such as alcohol and tobacco, are being used simultaneously.

Long-term brain effects may also be caused in part by other substances, such as marijuana. To better understand the role of marijuana and other substances in brain development, the Adolescent Brain Cognitive Development study or ABCD study is underway.