The association between cannabis and memory loss is not new and the stereotype stoner is often portrayed as someone who has trouble remembering things that had happened literally seconds ago. While this may be an exaggeration, the effect of cannabis on short term memory is definitely something experienced by all cannabis consumers at some point - is cannabis dangerous for your memory? Before we take a look at that question, let’s review the science to see what is happening inside the brain and how smoking or ingesting cannabis affects the memory.
Cannabis and memory: what happens to your brain?
The Endocannabinoid system (ECS) regulates many of the body’s core functions and processes including appetite, memory, sleep, emotional state and fertility. The body produces its own endocannabinoid molecules which bind to receptors in the ECS to keep the body’s system in a state of harmony. An example of this is endocannabinoids binding to a receptor to target an area of pain.
One of the things we know is that cannabinoids which are present in the cannabis plant act like external endocannabinoids, binding onto the body’s receptors (ie its endocannabinoid system). The most obvious example of this is THC binding to CB1 receptors in the brain to create the sensation we all know as a cannabis ‘high’.
CB1 receptors (Cannabinoid Receptor 1) are present in every part of the brain, but for the cannabis and memory link, we need to take a look at the hippocampus which is located deep in the temporal lobe. This part of the brain plays a critical role in learning and memory.
The effect of cannabis on short term memory
When you consume cannabis, THC enters the brain by binding on to the CB1 receptors. When this happens inside the hippocampus the presence of THC disrupts the process of memory formation which manifests itself in the loss of short term memory. Therefore, you can suddenly lose all context of that conversation that you’re in the middle of, or forget the name of the person you were just introduced to. It is also suggested that this process can affect the memories of an experience while being stoned, which is why there may be some truth in American comedian Charlie Fleischer’s observation that “If you remember the ‘60s, you weren’t really there…”.
Although such short term memory glitches are not exclusive to cannabis consumption, they are definitely a characteristic of getting stoned. A 2020 study into the effects of weed on short term memory concluded that more participants who had received a cannabis dose scored lower on a visual working memory task than those who hadn’t. Interestingly this occurred in a test involving 15 mg of THC, but at a dose of 7.5mg the effect on memory was much less significant.
If short term memory loss is causing an issue in your daily life, there is an easy solution. Stop smoking weed and the issue will disappear. Alternatively, ensure you have some structure to your routine – in other words, make sure your shit is done for the day before you smoke!
The effect of cannabis on long term memory
But how about the effects of weed on long term memory? Should you be concerned or anxious about long term memory loss or even dementia as a result of cannabis use? While this is an area which still needs to be explored in greater depth, so far the evidence suggests that longer term memories are not affected and casual cannabis use does not contribute to dementia. Nevertheless, research does suggest that the age you start consuming cannabis can have an effect on cognitive function, including memory.
Research has shown that those who started consuming cannabis young (and consumed frequently) - before their brains had fully developed - had temporal and frontal cortices that were thinner, which had an affect on memory, concentration and brain processing speed. Memory and concentration problems have also been identified in older cannabis consumers whose use is characterized as heavy.
Cannabis short term memory test
Do you want to test that short term memory? Take our test!
1) Memorize this list for two minutes. Then look away and write as many words as you can remember.
| Plant | Brown | Stem | Chair | Four |
| Orange | TV | Lime | Two | Turtle |
| Desk | Elephant | Seven | Leaf | Pistil |
| Nine | Calyx | Lamp | Monkey | Pink |
| Cat | Pot | Mouse | Yellow | Bed |
2) How did you do? Don’t worry if you did not get them all! Research suggests that the normal recollection is 7 (plus or minus 2 list items) - and this is for someone who hasn’t been consuming weed!
3) Stoned or not, you can boost your short term memory recollection by using a hack to help the brain. By clustering information into groups (ie placing individual items into collections) it makes it easier to remember. If you didn’t do it already, look for the 5 common ‘groups’ the above words belong to - furniture, plant parts, numbers, animals and colors.
4) With this memory tool, try the exercise again!