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Monday November 22, 2021

By Paul Barach

Reviewed By Mohammad Ashori, M.D. on Tuesday April 19, 2022

someone thinking Education

Does weed affect memory? According to many anti-drug PSAs and movies like Half Baked, Cheech and Chong, Harold and Kumar Go to White Castle, and Dude, Where’s My Car? — it does. 

Usually, in the movies this memory loss leads to some wacky antics. In anti-drug PSAs, it ruins your life. But is there any truth to the effects of cannabis on Memory?

Cannabis and Memory in the Media

As much as people might be tempted to trust stoner comedies and agencies that make their money by demonizing cannabis to provide their cannabis advice, the answer is more complicated. It involves interactions with receptors in the brain that include both cannabinoids like THC and CBD, but also with chemical compounds called terpenes, which can affect memory.

None of this was mentioned once in the film Dude, Where’s My Car?, so let’s dive into cannabinoids, terpenes, and memory.

First off — to state the fairly obvious — not all cannabis is the same.

Each strain, even each plant, can vary, sometimes widely. What makes all the difference is the levels of cannabinoids and terpenes contained within each plant, as well as how these different combinations interact with each individual’s brain chemistry. Not all cannabinoids create the same effects in each person’s brain, and the same can be said for terpenes.

While most consumers are familiar with cannabinoids like THC or CBD, many people know far less about terpenes. Before exploring terpenes and memory, it’s worth delving briefly into what terpenes are and how they affect the brain.

What are Terpenes?

Basically, terpenes are essential oils that can be found in many plants all over the earth. The “essential” in essential oils simply refers to oils with the essence (smell/flavor) of the plant.

These oils are highly volatile, which is why they evaporate so quickly. This releases the plant’s specific smell into the air and towards the scent receptors of any nearby animal.

For example, pinene terpenes are what waft off pine needles in the forest, giving them that woodsy, lemony smell. Terpenes can also have a beneficial physical or emotional effect on some people, which forms the basis of aromatherapy and essential oil pyramid schemes. For example, Dr. Ethan Russo has noted pinene’s function as a bronchodilator, which can help open lung passages.

trichomes on a cannabis plant
Terpenes can be found in the trichomes of cannabis plants.

In the cannabis plant, there are over 100 different identified terpenes that are created alongside cannabinoids like THC and CBD inside marijuana’s trichomes. Resembling tiny glass mushrooms, these sticky, shiny little crystals cover the leaves and the buds of the cannabis plant. Once released into the air, terpenes attract helpful insects that pollinate the plant as well as repel any harmful pests that can cause damage. 

How a cannabis strain tastes and smells all depends on its terpene profile. How it affects the individual consuming it also directly correlates to the terpenes, some of which bind to receptors in the brain similar to cannabinoids like THC or CBD. Some terpenes can have beneficial effects like promoting relaxation.

Linalool has been shown to have anti-anxiety properties, as has Caryophyllene. Many other terpenes have documented effects as well. Others can have less than desirable effects, like promoting anxiety.

These effects can also vary from person to person, interacting with each individual's unique biochemistry.

Common cannabis terpenes chart: Limonene, Pinene, Myrcene, Linalool, Caryophtyllene

To make things even more complicated, both the mental and physical effects of any one terpene can depend on the presence of other terpenes and cannabinoids, as well as what percentage of each is in the cannabis.

Think of cannabinoids like THC as the cool/famous friend getting all their other friends (the terpenes) into the party (the brain receptors). Each friend’s personality affects how the other friends interact with each other, and how the party will go in general. This is what is known as the “entourage effect.” 

Does THC Affect Memory?

Now that we’ve covered terpenes, it’s worth briefly exploring whether THC actually does affect memory and how much.

In some studies, it’s been shown that cannabis users may have a harder time making new memories while under the influence. Mostly these memory difficulties are minor, but cannabis is an intoxicant and high enough doses can cause a “green out” effect where memories while under the influence get a little hazy.

Cannabis consumers under the influence can also have trouble with short-term memory recall while stoned and for a couple of hours after the weed wears off. This same issue hasn’t been found with long-term memory. Of course, other studies have shown that this effect decreases in consumers who use marijuana frequently, so it may be an initial tolerance issue such as with consuming cannabis and time perception. When we bring CBD into the mix, things get even more complex, as it may help to diminish THC’s effects on memory.

Someone who looks like the forgot something
Cannabis may affect short-term memory while under the influence. photo credit

So, for example, if you and your friend are infrequent pot smokers and you decide to burn one down while out in an unfamiliar part of the city, you may walk around the block and ask “Dude, where’s my car?” This short-term memory recall can be affected by smoking weed.

However, you would still be able to answer long-term memory questions such as “Dude, what color is your car?” and “Dude, what was your first car?” 

How long-term these effects last is debatable. Some studies have found that cannabis use, especially while young brains are developing, can impair the memory-forming parts of the brain. Other studies have found that long-term use can affect verbal recall — your ability to remember words — but not long-term memory.

As with many things in life, an argument can be made for moderation. Are you puffing away every hour or toking here and there? This article isn’t meant to argue for one or the other - do what you think is best for you. For now, let’s unravel this a bit further.

Terpenes and Memory

So, how do terpenes fit into all of this?

Generally, there are six terpenes that are the best known and most understood; these are Limonene, Pinene, Myrcene, Caryophyllene, Linalool, and Humulene.

Out of these six, pinene seems to have the most effect on memory and is linked to better focus as well. Through the entourage effect, strains high in pinene seem to reduce the short-term memory loss that can occur with other strains. 

The memory impacts may be due to THC or some compound within the cannabis plant increasing levels of acetylcholinesterase in the brain. While there is no reason for anyone outside the scientific community to know the name of this molecule, just know that it breaks down the molecule acetylcholine, which is responsible for transmitting information between nerve cells.

Pinene may penetrate the blood-brain barrier, where it could act as an inhibitor for acetylcholinesterase, which breaks down the molecule that affects memory. With more acetylcholine floating around, one may feel more lucid and focused, with improved memory.

Further studies, of course, will need to be performed to better understand the effects of terpenes on memory, but even these may not be conclusive due to the complexities of the entourage effect.

Perhaps a strain high in Pinene can help blunt short-term memory loss while stoned, but a combination of Myrcene and Linalool in the right amounts could do the same. Or perhaps they could blunt the effects of Pinene.

Plus, the level of THC in the strain itself can have an effect, as well as the levels of CBD which also may increase memory.

And of course, this all depends on the brain chemistry of the person consuming it, as well as how often they consume weed.



So, does weed affect memory? Yes, and it’s complicated.

Do terpenes also have an affect memory? Yes, and it’s complicated.

However, if you don’t want to be asking “Dude, where’s my car?” after your next bowl, your best bet is to find the most evergreen-smelling strain you can and go enjoy yourself. Or maybe just take a photo with your phone of where you parked.

Frequently Asked Questions

Do Terpenes Affect Memory?

Some terpenes, such as pinene, have been shown to potentially help with focus and memory. However, it is possible that others induce anxiety or lack of focus. More study needs to be done to find out which terpenes affect memory and to what extent.

Does THC Affect Memory?

THC can affect short-term memory, but its impact on long-term memory is not fully understood.

What strains leave your memory intact? Share in the comments!

Photo Credit: Paola Aguilar (license)


Paul Barach Paul Barach

Paul Barach is a Seattle-based freelance writer, editor, and author with experience creating well-researched, edited web articles covering cannabis news, culture, history and science. Paul is a regular contributor to PotGuide and has also contributed to publications such as, SlabMechanix, Litro, and The Trek. He prefers to spend his free time outdoors and most recently hiked the Pacific Crest Trail. So far he has only fallen into the La Brea Tarpits once. You can follow him on Instagram @BarachOutdoors and stay up to date professionally through his LinkedIn page.

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Expert Medical Reviewer

Mohammad Ashori, M.D. Mohammad Ashori, M.D.

Mohammad Ashori, M.D. is a board-certified physician practicing in Los Angeles, CA. He attended UCLA medical school and completed his family medicine residency at UCLA as well. His career started out at a large HMO at Kaiser Permanente which he left in 2016 to work on the then-burgeoning field of telehealth. Since then he has worked with numerous healthcare startups focusing on patient education, empowerment, and access. He is passionate about the science of clinical medicine but doesn't like to stray too far from one-on-one clinical care. As of 2021, he is practicing in various urgent care in the Los Angeles area.

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