Ten Myths About Marijuana That No One Should Believe – Part 6: Marijuana causes memory loss and a general reduction in logic

From the original Jeff Spicoli to everyone’s favorite burger seeking duo Harold and Kumar, the idea of the lazy and forgetful marijuana smoker is a stereotype that has been embraced by cannabis culture and prohibitionists alike. One would be hard pressed to find a recreational cannabis smoker that hadn’t experienced some level of forgetfulness associated with marijuana. That being said, it is important to understand the reality behind this comical image of absent-mindedness.

Myth #6 – Marijuana causes memory loss and a general reduction in logic

Of all the stigmas associated with cannabis consumption, the idea of memory loss has the least amount of long-term studies. On that basis alone one must consider the possibility that the entire discussion could change as future studies come into light. Until that time all one has to go on is the research that has been done to date. To fully understand the effects of any substance on one’s memory, it is important to understand how one’s memory works. 

Everyone has three different forms of memory, which are: long-term memory, short-term memory and working memory. This is quite an over simplification of the incredibly intricate workings of the human brain but works for the purposes of this discussion. Long-term memory is a vast store of knowledge and a record of prior events that each person builds throughout their lives. Short-term memory is the brain’s ability to recall ideas and information that pertain to a current situations that have yet to be formed into long-term memories. Working memory is not completely distinct from short-term. It is used to plan and carry out behavior. One relies on working memory to retain the partial results while solving an arithmetic problem without paper. 

The first and most important distinction to make when discussing marijuana’s effects on memory is the very big difference between the effectiveness of memory recall while under the influence of cannabis and while sober. Marijuana has been shown to affect short-term memory and one’s ability to form new memories while under the influence, however, has little to no effect on one’s ability to recall memories formed before or after. In other words marijuana does not harm one’s long-term memories but makes it more difficult to retain information while intoxicated. Many feel that alcohol causes much more impairment on short-term and long-term memory, and its effects are not limited to the time of impairment, but cause lasting detriment to the memory.

A study following nearly 2000 young Australian adults for eight years found that marijuana has little long-term effect on learning and memory, and any cognitive damage that does occur as a result of cannabis use is reversible. Participants were aged 20-24 at the start of the study, which was part of a larger project on community health. Researchers categorized them as light, heavy, former or non-users of cannabis based on their answers to questions about marijuana habits.

“The adverse impacts of cannabis use on cognitive functions either appear to be related to pre-existing factors or are reversible in this community cohort even after potentially extended periods of use.” – Robert Tait at the Centre for Mental Health Research at Australian National University

As with any substance, using marijuana in excess can cause side effects. However minimal, one who chooses to be under the influence of marijuana twenty-four hours a day will experience some loss in cognitive function. Comparatively, one who chooses to be under the influence of alcohol twenty-four hours a day will most likely shorten their life substantially and have quite a bit more than a loss of brain function. A study conducted by Harvard Medical School shows that even this type of excessive marijuana use and consequent perceived harm is completely reversible. If and when one chooses to discontinue the excessive use, the brain function will return to normal. This in itself disproves years of marijuana propaganda. All one must do is take a break, and all negative memory associated effects are reversed, assuming there are any in the first place.

Published in a March issue of Addiction Biology, a team of Dutch scientists found no changes in the working memory abilities of heavy cannabis users who were monitored for three years. The study “adds to the literature showing that regular cannabis use may not necessarily impair brain functioning,” explains lead author Janna Cousijn, PhD, a researcher at the University of Amsterdam’s Department of Developmental Psychology. Working memory plays a key role in learning. Dr. Cousijn and her colleagues conducted the study on 49 young adults, 22 who were considered heavy cannabis users and consumed marijuana five days a week on average. This study shows that cannabis does not impair problem solving or deductive logic using working memory. However, recent articles have been circulating that claim contradictory findings.

There have been many articles recently released showing a new study proclaiming that marijuana causes irreversible damage to one’s memory and brain function. What is consistently skipped over in many of these articles is the fact that this study was conducted on adolescent use. Use of any substance, be it alcohol, tobacco, or even caffeine can have lasting effects on a developing brain, so it becomes quite irrelevant to make the focus on the effects of marijuana versus any other recreational substance. A vast majority of those shown to have negative effects attributed to long-term marijuana use, have a substantial correlation to those who started at a young age. Therefore the majority of those effects can be attributed to the use of a mind altering substance with a developing brain, whether it be cannabis or any other. 

The truth of this topic, clouded by years of misinformation, can be hard to decipher. Relying solely on science and the conclusive information that the studies conducted have produced, it becomes quite clear that the idea of the classic stoner that can barely function due to marijuana use, is vastly overstated. One’s short-term memory can be affected while under the influence, but no real lasting cognitive side-effects are associated with marijuana, outside the category of adolescent use of any impairing substance. It is becoming clear that many of the most ingrained stigmas associated with this plant are exaggerated, if not completely made up. This myth has elements of truth to it, but overall, the idea that marijuana will leave you a mindless and dysfunctional human being is busted. 

[accordion title=”Top Ten Marijuana Myths Continued” close=”1″]Myth #1 – Marijuana is More Harmful Than Alcohol, Tobacco and Prescription Drugs
Myth #2 – Marijuana is Addictive
Myth #3 – Marijuana Causes Schizophrenia 
Myth #4 – Marijuana Has no Proven Medical Benefits
Myth #5 – Marijuana Use Leads to Harder Drugs – “Gateway Theory”
Myth #6 – Marijuana Causes Memory Loss and a General Reduction in Logic
Myth #7 – Marijuana Contains Over 400 Chemicals
Myth #8 – Marijuana Has Yet to be Subjected to Adequate Scientific Study
Myth #9 – The Marijuana Movement is Just an Excuse for People to get High
Myth #10 – Opposition to Marijuana Legalization is Driven Entirely by Cautious Prudence[/accordion]

Sources: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2657600/, http://healthland.time.com/2011/07/19/study-marijuana-not-linked-with-long-term-cognitive-impairment/, http://www.leafscience.com/2014/10/21/marijuana-memory/