Does Smoking Marijuana Affect Memory?

does weed mess up your memory

Thanks to mainstream media, we’ve come to accept stoners as loveable buffoons. Movie and television depictions of potheads paint the picture of dimly-lit Schnucks who can never seem to remember where they’ve put their keys…or their cars. It’s fun to watch, and we laugh at the blatant stupidity of these characters. After all, they’re just harmless stoners. But what does science say about marijuana use and memory? Does smoking weed actually cause memory loss? At present, the jury is out on the matter. Studies are showing conflicting evidence, making it hard to nail down any conclusive evidence on either side of the fence. Only a few conclusions can be made at this point—here is what we know:


There are three types of memory: sensory, short-term, and long-term. Each has a specific function and “run-time.” For example, short-term memory is used to commit information in the span of 30 seconds. After this time, the information is likely to disappear, unless actively committed to long-term memory.


CB1 receptors, which are primarily found in the spinal cord and the brain, react to the THC compound in marijuana. The CB1 receptors are located in the hippocampus, or the memory center of the brain. When THC travels from the bloodstream to the brain, the endocannabinoid system is activated, and memory function is temporarily altered.


A study by JAMA International Medicine has demonstrated a correlation between habitual marijuana use and short-term memory loss. JAMA’s research studied nearly 3,400 American marijuana users over the course of 25 years. The conclusion of the study shows a link between heavy pot use and lower verbal memory. The “heavy use” is defined as smoking every day for at least five years. Participants in this category scored lower on cognitive ability assessments that measured focus, memory, and mental acuity in decision making. JAMA’s research utilizes a new unit of measurement coined, “marijuana years.” If a person smokes every day for an entire year, that is considered one marijuana year. The major limitation of the research, and all research for that matter, is causality. At this time, it’s hard to conclusively say whether marijuana caused the lower cognitive scoring, or if people with lesser cognitive function are more apt to abuse marijuana.


does weed make you forget things

A separate study out of New Zealand suggests that heavy marijuana use in adolescents can lead to a major drop in IQ points, which cannot be recovered in adulthood. While this point has been heavily refuted by other studies, there is something to be said for marijuana use in adolescents. There is a growing concern over how marijuana affects memory and learning capabilities in young adults, whose brains are still developing. Only future research will be able to clarify this point and bring to light any real threat to adolescent brain development and memory loss.


Memories are best accessed in the environment in which they were formed. This is why some students prefer to listen to music when they study. They find it’s easier to remember test material when they can associate the information with a song. In the same way, some scientists believe that stoners suffer from context-dependent memory loss. If a heavy marijuana user decides to sober up for a day, they may find it hard to retrieve memories they made while they were using the drug. This can be especially difficult if they have been using weed for a long period of time. The reverse is also true. Habitual users may find it hard to recall memories they made in their sober hours.


In the short-term, yes. Smoking marijuana ignites a chemical reaction in the brain that stunts or alters the ability to recall memories. However, long-term damage to short-term memory has not been conclusively proven, though it would seem science is leaning in that direction. Once again, this area of medical research is stymied by regulations and lack of research. So, does smoking weed affect your memory? Only time will tell. For now, follow the same rule you would with anything else—everything in moderation.

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