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To easily understand the effects of marijuana on the brain, you need to understand cannabinoids. Weed as a plant has more than 480 known naturally occurring substances. Out of these, about 100 are classified as cannabinoids. Cannabinoids probably the biggest reason why most people use marijuana.

Researchers have spent a lot of time and effort, trying to understand two of these cannabinoids: tetrahydrocannabinol (THC) and cannabidiol (CBD). CBD is mostly used as a dietary supplement, it is non-psychoactive, and it helps the body maintain wellness. Manufacturers extract it from low THC content hemp, purify it and package it as CBD products. It is this extract that is processed to produce capsules, gummies, and other such products.

Tetrahydrocannabinol effects on the brain are mostly adverse. This is because it is psychoactive.  Besides being psychoactive, this cannabinoid is beneficial to the body in some ways.

It is an antiemetic and has been found useful in the management of cases of extreme nausea, such as nausea that comes as a side effect to chemotherapy. THC is also a bronchodilator, and thus, it helps with the dilation of airways in case they are constricted as it happens during asthma attacks.

When we talk about the effects of marijuana on the brain, we mostly refer to the effects of THC.  It is difficult to understand marijuana’s impact on the brain without knowledge of how it is received into the body.  The following section describes how THC connects with the body once a person smokes or otherwise ingests it.

The Endocannabinoid System

This is also known as the ECS. The endocannabinoid system in an organ system that connects with cannabinoids. It is the platform from which cannabinoids influence the body.

The endocannabinoid system is not made for plant cannabinoids like CBD and THC. It is made for use by cannabinoids that the body itself generates from time to time when there is a need for them. These internally generated cannabinoids are known as endocannabinoids.

All vertebrates have the endocannabinoid system.  The next logical question at this point would be, “why does the body need endocannabinoids?”

All biological functions of the human body operate within a specific range of parameters. For example, the body works optimally within a particular temperature range, too much of it or too little would cause the body to malfunction.

The body needs hormones and other biochemicals to be within a specific range, and it malfunctions if these elements are not maintained within the right balance. This balance is referred to as the homeostatic balance. It is the role of the endocannabinoid system to get homeostasis back to the correct range.

The endocannabinoid system is comprised of three parts: Endocannabinoids, cannabinoid receptors, and metabolic hormones.

Endocannabinoids are cannabinoids that occur naturally in the body. None of them is stocked in the body, and the body only releases them when there is a need. Once the endocannabinoids have restored homeostatic balance, metabolic enzymes destroy them so that none remains until more are produced by the body when needed.

Endocannabinoids are in many ways similar to CBD and THC. Their similarities make it possible for CBD and THC to be received by endocannabinoid receptors.

As earlier observed, the body destroys endocannabinoids immediately they are done playing the role for which they are made. Thus when plant cannabinoids are introduced to the body, they are free to connect with endocannabinoid receptors.

When EC receptors connect with THC, it reacts differently from when it connects with endocannabinoids. The ECS’ reaction to THC is what affects the brain, and if marijuana is used consistently over a long time, it may end up having adverse effects on the brain.

THC and the Endocannabinoid System

THC and the Endocannabinoid System

What are marijuana effects on the brain? The metabolic hormones that are supposed to destroy cannabinoids after some time do not work effectively when it comes to THC.  This means that THC remains active in the ECS for much longer, and this impairs brain function for longer that is needed.

How Effects Manifest

If you are seeking an answer to the question, “what does marijuana do to your brain?” The following section will discuss some effects of THC on the brain and provide you with the answers you seek.

1. Psychosis

A person is said to be experiencing a psychotic break or to be in a psychotic episode if they are unable to tell the difference between their imagination and reality.

Psychosis is the main symptom of schizophrenia, and people who use marijuana are more likely to be diagnosed with schizophrenia and other forms of psychosis than people who have never used weed. This, therefore, can be said to be one of the main symptoms of marijuana brain damage.

Besides schizophrenia, studies have shown that marijuana is highly likely to cause psychosis even among people who do not have schizophrenia. If a person uses marijuana regularly for too long, this effect may cause them to lose control of their minds altogether.

2. Reduced IQ

Marijuana and memory don’t mix well. A study conducted in New Zealand showed that people who started smoking marijuana in their teenage years experienced a drop in their IQ later in life. Their IQ dropped by 8 points, which is significant enough to turn a straight ‘As’ student into a ‘B’ student.

According to the study, even teenagers who stop smoking weed after some time have their IQ drop in their adult years. It was, however, observed that people who started smoking weed after their teenage years didn’t experience a similar decline in IQ later in life. Marijuana memory loss and other cognitive impairments are the reasons for this reduced IQ.

The specific reason why this drop occurred among teenage users has not been established. Still, it could be because adolescent brains experience many changes in their chemistry, making them more vulnerable to the effects of THC.  According to the New Zealand experiment, these changes occurred in teenagers who took marijuana an average of four times a week.

3. Reduction of the Orbitofrontal Cortex (OFC)

A study conducted on 48 chronic marijuana users and 62 non-users showed that those who use marijuana had less grey matter in the cortex mentioned above.

This cortex is responsible for impulse control, and it also helps with response inhibition, among other things. When this region of the brain grows smaller, it means that the person is not able to control their impulses as effectively.

Like with other effects, this reduction is higher among people who start using marijuana in their teenage years. Understanding the impact of a reduced orbitofrontal cortex was aided by Phineas Gage, whose OFC suffered extensive damage in an accident leading causing him to have much less social inhibition than he had before the accident.

4. Increased Brain Connectivity

The answer to the question, “what does THC do to the brain?” is not all negative. There is one positive outcome because chronic marijuana users also have increased brain connectivity. The increased connectivity means that information travels faster across the brains of chronic marijuana users. This state of affairs may be attributed to the reduction of grey matter in the OFC, but its cause is not known.

5. Distortion of the Brain Reward System

Research conducted among chronic marijuana users showed that their brains showed a higher affinity to marijuana. This was in comparison to non-smokers, who considered other neutral things such as fruits to be more important. This is an indication that chronic use of weed distorts the user’s normal brain function and causes the user to become dependent on pot. It is due to this change in the brain’s reward system that marijuana becomes addictive over time.

6. More Neural Noise

Neural noise refers to electrical fluctuations in the neurons which happens without external stimuli. Electrical variations are how the brain receives information concerning stimuli. A study published by the Journal of Biological Psychiatry showed that people who take THC experience elevated levels of neural noise when compared to those who didn’t have THC in the system.

When electrical signals in neurons fluctuate without external stimuli, it leads to psychosis, delusion, and hallucinations; all these are as a result of THC effects on the brain. A person experiencing such fluctuations is not able to differentiate between their imagination and reality.

7. It Makes Neurons that Suppress Appetite Less Effective

Research conducted on mice in 2015 showed that manipulation of the cellular pathway through which marijuana moves reduced the effectiveness of appetite-suppressing neurons. Suppression of those neurons caused the mice to have a higher appetite than usual.   While this study has not been conducted on humans, it is an acknowledged fact that cannabis increases appetite for those who use it. This effect on the brain could be useful for people who are seeking to improve their appetite or to gain weight. People going through chemotherapy usually find it challenging to eat, and marijuana can help them find their appetite.

Effects of CBD on the Brain

As earlier mentioned, the two best known active ingredients of marijuana are THC and CBD. The list above has detailed the effects of THC on the brain. Let us now talk about the other part of weed and how it interacts with the brain.

Reacts with Dopamine

When CBD connects with dopamine, it helps the body release more endocannabinoids, which in return, work towards the restoration of homeostasis. The additional endocannabinoids can also regulate the users’ cognitive functions.

It Connects with Serotonin Receptors

When it connects with serotonin receptors, CBD slows down the brain’s ability to receive signals of pain and other undesirable messages from the body. The outcome of this connection and signaling is reduced pain, less depression, less psychotic breaks, among others. It is this ability that has made CBD popular as a wellness product.

It connects with Opioid Receptors

The reason why addicts crave their drug of choice is the need to gratify opioid receptors. When a person stops using drugs, they experience withdrawal symptoms and cravings that can cause them to relapse because these receptors need to be rewarded. If they do not relapse, they experience withdrawal symptoms that make most recovering addicts miserable.

When a person takes CBD, it connects with the opioid receptors helping them avoid withdrawal symptoms even when they don’t take the drug to which they are addicted. CBD has positive effects on the brain.

However, one might be tempted to conclude that the adverse outcomes from THC outweigh any good CBD does. On balance, you should answer ‘negatively’ if someone asked, how does weed affect the brain?

Marijuana Effects on Teenage Brain

Marijuana Effects on Teenage Brain

Different people react to weed differently. Many factors, including genetics, brain chemistry, etc. inform the variance in reaction. On average, however, marijuana effects on teenage brains more adverse than adult brains. These differences can be attributed to rapid changes that go on in adolescent brains.

Teenage boys with a genetic predisposition to schizophrenia are more likely to get the condition if they smoke marijuana. Some studies suggest that teenagers with a genetic predisposition to schizophrenia are also likely to indulge in smoking marijuana. Schizophrenic teenagers’ affinity to marijuana makes it difficult to conclude whether marijuana is a cause of schizophrenia.


This article discusses the effects of the use of unprocessed marijuana as a recreational drug. As observed, THC causes most of the adverse effects that are associated with marijuana on the brain. It is important to note that some strains of marijuana have very low THC content, and they can, therefore, be used without causing adverse effects on the brain.

Technology has also made it possible to isolate certain elements of the marijuana plant to be used to meet the specific need for which it may be deemed necessary. Due to this technology, there are marijuana products in the market that are ideal for the management of anxietysleeplessnessdiabetescancer and other conditions.

Is weed bad for your brain? This is a question many teenagers ask. The answer is an emphatic ‘yes.’

One of the most important takeaways in this discussion is that cannabis affects teenage brains in very significant ways. These adverse effects may or may not be immediate, but they always manifest. It is a matter of paramount importance for teenagers to avoid the use of weeds except under the guidance of a medical professional.