Effects of Marijuana Use

Effects of Marijuana Use

Effects of Marijuana Use: How Weed Affects Your Mind & Body

Scientists who have been looking into the effects of marijuana for many years have made several important discoveries. They figured out what makes marijuana work; they also found where and how it works in the brain. They called this new system the endocannabinoid (EC) system. The EC system, named after the marijuana plant Cannabis sativa and its active ingredient delta-9-tetrahydrocannabinol (THC), is a unique way for the brain and body to talk to each other. It affects many vital functions, such as how a person feels, moves, and reacts.

Cannabinoids are the natural chemicals made by the body that works with the EC system. Like THC, they work with receptors to control these essential body functions. So, what is unique about the EC system, and how does THC's effect on it affect a person's memory, risk of accidents, and even their ability to become addicted.

When you use marijuana, these things can happen:

What makes cannabinoids different from other neurotransmitters is how they work:

Neurons in the brain send chemical "messages" to each other and to the rest of the body to talk with each other and with other cells. These messages help us feel, think, and act in a way that makes sense. Usually, chemicals called neurotransmitters are released from a neuron (a presynaptic cell), travel across a small gap (the synapse), and then attach to specific receptors on a nearby neuron (postsynaptic cell). 

But because it works "backward," the EC system sends its messages differently. When the postsynaptic neuron is activated, cannabinoids, which are chemical messengers of the EC system, are made "on-demand" from fat cells already in the neuron. Then they leave that cell and go back to the presynaptic neuron, where they attach to cannabinoid receptors.

So why does this matter? Since cannabinoids work on presynaptic cells, they can control what happens after these cells are activated. In general, cannabinoids work like a "dimmer switch" for presynaptic neurons, limiting the number of neurotransmitters (like dopamine) released. This changes how messages are sent received, and processed by the cell.

How does THC change the EC system, and how do people act?

When a person smokes marijuana, THC overwhelms the EC system and quickly binds to cannabinoid receptors in the brain and body. This stops natural cannabinoids from doing their job of fine-tuning how neurons talk to each other, which can throw the whole system out of balance.

THC has a wide range of effects because cannabinoid receptors are in so many parts of the brain and body. It can slow down a person's reaction time, making it hard to drive or play sports, mess up a person's ability to remember recent events, make them anxious, and change their ability to make decisions. THC also affects parts of the brain that make people feel good. This is what makes people feel "high." But THC can change the way the EC system works in these parts of the brain over time. This can cause problems with memory, addiction, and mental health. Figure 2 shows where cannabinoid receptors are in the brain. 


Marijuana, weed, pot, dope, grass. They all refer to the same drug from the cannabis plant and have different names. It can be smoked, vaped, drunk, or eaten. Most people smoke pot for fun and entertainment. But more and more doctors are giving it to people with certain medical conditions and symptoms. Marijuana has chemicals that change the way your brain and bodywork. It can be addicting, and it might be bad for some people's health.

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