3 MIN READ | General

Jason Smith

What are the Wide Range of Effects of Marijuana for Brain and Body?

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Jason Smith, (2018, September 26). What are the Wide Range of Effects of Marijuana for Brain and Body?. Psychreg on General. https://www.psychreg.org/effects-of-marijuana/
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Marijuana is made from parts of the cannabis plant, which is usually dried and shredded, and the most important part of the plant are the flower, leaves, and stems. Marijuana can be smoked, brewed, vaped, or used in food – but there’s also topical products that contain marijuana. 

The different ways of taking marijuana all generate different responses in the body – so someone who’s vaping pot may start to feel woozy almost immediately; and of course the effects will probably subside faster than when you ingest marijuana.

So what are the effects of marijuana on the mind?

Cannabinoids reach the pleasure centres of the brain in much the same way as cocaine or heroin; and based on how much you take, and how strong the strain is, marijuana can give you a rather nice feeling of euphoria. Long-term effects are determined by how much you use, and things like the THC levels present in marijuana. 

Although the exact effects are hard to measure (everybody’s experience with weed is unique), there are some basic aspects of cannabinoids that are common with all users. For instance,a change in mood is reported across the board with all types of marijuana products, and some of the most common theme is a temporary feeling of elation, short-term memory loss, relaxation, sedation, and pain relief. 

Here’s a quick breakdown of what happens in the mind when you smoke or ingest marijuana:

Impaired neural connectivity

The National Institute on Drug Abuse states that differences in brain scans among people who use marijuana are harder to interpret than people realise, and so for instance, MRI scans of teenagers who use marijuana regularly have suggested that there could be some level of neural impairment in certain regions of the brain.

Loss of IQ points 

One study found that frequent marijuana use could lead to a drop average in IQ points in mid-adulthood; and that same study also found that teenagers to use marijuana (particularly in adolescence but later quit before it causes significant damage in the body did not show any signs of a loss in IQ points. 

The fact that it’s so hard to measure the way marijuana affects individuals, most experts just recommend a minimum dosage for adults, and for teenagers to stop using it altogether. 

Changes in brain function

The cannabinoids present in marijuana can cause subtle changes in the brain and cause relative impairment (so much like what drinking can do to a person) but the difference is that the impact is mostly mental, as opposed to alcohol, which seems to hit you in the head as well as the knees.

Cognitive function may be enhanced or reduced, based on factors such as the dosage and the quality of the strain, but there’s also the issue of combining drugs.

When you have other drugs in your system, then marijuana could have more extreme effects (such as rendering you incapable of driving or operating machinery). 

Anxiety and depression

The interesting thing about cannabinoids is the fact that in some instances (or indeed in some people), they can reduce anxiety; but when dosages hit a certain point, the effect can be opposite – so you find that your heart rate elevates and that causes you to freak out, making everything worse. 

But normally, marijuana can be an effective tool for relaxing when you’re coming from a place of high stress.  

Effects of marijuana on the body

  • Treatment for glaucoma – One of the most common reasons for people using marijuana in the past (before the lax federal regulations) was glaucoma. But the difference brought on by expansion of blood vessels in the brain can help to treat eye conditions like glaucoma. 
  • Reduced nausea and vomiting – As you may already know, cannabinoids present in marijuana are commonly used to treat nausea, and can be prescribed to people on cancer medication, who often experience nausea that can’t be easily managed with pharmaceuticals. 
  • Pain relief – Cannabinoids such as THC and CBD have been studied for their pain-reliving properties, and have been quite effective at managing different kinds of pain including arthritic pain, muscle pain, joint pain, and so on. Studies on CBD and its effect on pain all revolve around the endocannabinoid system (ECS), and more research is needed to learn more about the healing mechanisms of cannabinoids in the body. 
  • Healing of spinal cord injury – One study shows how marijuana can be effective at improving quality of life for people with back bone injury, and also facilitating mobility – which can be excruciating when your back is out of alignment. 

Are there any long-term risks of using marijuana?

It really depends on the way a person uses cannabis, and so it’s wise to practise healthy habits when using any kind of drug, because of the obvious likelihood of addiction and its implications. 

Resources from reputable government or private health institutions can help shed some light on available research so that you can come up with your own conclusions about the perceived dangers of using cannabis. Keep in mind that individual cannabinoids (such as CBD) can also provide many of the therapeutic effects of marijuana, but without the psychotropic element. 


Jason Smith did his degree in psychology at the University of Edinburgh.  He has an ongoing interest in mental health and well-being. 


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