Does cannabis make you forgetful?
A look at the science.
Is cannabis memory loss real? We spoke with Emma Chasen, plant science expert, industry consultant, and cannabis educator with the Sativa Science Club, to learn what’s going on in the brain with cannabis and memory. Chasen walks us through the science to see if there’s any truth to the age-old stereotype that smoking weed makes you forgetful.
What’s going on in the brain?
As you’re probably aware, there are many different types of memory, from short-term and working memory to verbal, spatial, and long-term memory. But Chasen explains there’s one neurotransmitter that regulates all types of memory: Acetylcholine.
“Acetylcholine is the main neurotransmitter that regulates memory and it can regulate short term, long term, as well as diseases like dementia and Alzheimer’s and other kinds of memory loss and amnesia experiences,” explains Chasen.
To understand the mechanisms at work, we also have to understand that there’s an enzyme that breaks down acetylcholine, known as acetylcholinesterase. According to Chasen, memory problems can be created by having too much or too little acetylcholine in the brain. The enzyme acetycholinesterase works to try to keep your acetycholine at optimal levels.
Here’s where cannabis memory loss comes in: THC is an acetylcholinesterase inhibitor, meaning it stops or “inhibits” the enzyme from breaking down more acetylcholine. “That’s good if you need more acetylcholine, not so good if you don’t need more,” says Chasen. “So that’s where THC can negatively impact short-term memory, specifically.”
Basically, THC is interfering with our brain processes that regulate memory by inhibiting acetylcholinesterase. But here’s the kicker: this impairment only lasts as long as you are “high.” Once the effects of THC wear off, so does the minor cannabis memory loss.
“There’s no research to support that prolonged use of THC will actually mess up your spatial memory [or other types of memory] in the long term. But in the short term, it can definitely have some negative side effects,” says Chasen.
The power of CBD for cannabis memory loss
If THC and CBD were a good cop, bad cop crime-fighting duo, CBD would definitely be the good cop. CBD, the non-intoxicating cannabinoid, is known to counteract many of the effects of THC and that includes cannabis memory loss.
“CBD, when in conjunction with THC, can actually help to optimize your levels of acetylcholine,” explains Chasen. “So, if you are consuming something that has a significant concentration of THC but also has a significant concentration of CBD, then you’re less likely to experience memory deficits or memory issues. Again, specifically related to short-term memory.”
Therefore, in order to avoid any cannabis memory loss, look for strains with high levels of CBD, especially those with a ratio of 1:1 or 2:1 CBD:THC. Some popular, high CBD strains include:
Don’t forget about terpenes
THC and CBD aren’t the only compounds in cannabis that affect memory. Some terpenes, like Pinene, also play a part in reversing the short-term cannabis memory loss from THC.
Pinene was named for its pine aroma, but it also has medicinal properties. It’s one of the “major” terpenes in cannabis and also has anti-anxiety, anti-inflammatory, and bronchodilator effects. Some strains high in pinene to minimize your cannabis memory loss include:
THC and the aging brain
In addition to certain strains and cannabis compounds affecting memory differently, the dose also affects THC’s memory impairment abilities. A 2017 study in Nature found that low doses of THC enhanced the memory and overall cognition in older mice. What’s more, a 2018 study found that THC interacts with memory in a “biphasic and age-dependent” way, meaning, while low doses of THC helped older mice, it impaired younger mice in the short term, no matter the dose.
Cannabis’ potential for Alzheimer’s
Chasen breaks down the research for us in more depth: “[In] patients with Alzheimer’s…we’re looking at natural accumulation of the amyloid-beta protein, that is negatively affecting memory. The accumulation of this protein causes Alzheimer’s and THC has the ability to reduce the protein and also prevent it from being made again or accumulating further. That also helps older patients specifically who are predisposed to Alzheimer’s.”
Cannabis memory loss is not more than short-term
THC’s effect on memory in the short term is one of the herb’s only negative side effects. More importantly, there is no evidence that cannabis impairs memory in the long term, so it’s time to put the cannabis memory loss myth to bed.