Marijuana has been a subject of controversy ever since it was first prohibited in California in 1913. Since then, there followed a series of legalizations and prohibitions that eventually ended with the drug being classified as a Schedule 1 narcotic. In a recent study to view the actual long-term effects of cannabis on the human brain, researchers revealed that smoking cannabis every day for five years reduces short term memory.
The large scale study and “marijuana years”
The study, led by Professor Reto Auer from the University of Lausanne, focused on a sample of 3,385 Americans and their marijuana smoking habits over the course of 25 years.
Out of the 3,385 participants, only 8% or 311 of them smoked cannabis every day for 5 years or more.
After the observation period was over, the researchers had the subjects engage in whole battery of tests in order to assess their cognitive functions and abilities.
For better quantification of the data, the team came up with a term for the frequency of marijuana consumption.
Marijuana years, as the researchers referred to them, are each year of daily marijuana intake.
For example, smoking cannabis every day for a year constituted one marijuana year, just like smoking it once every other day for two years, or once a week for seven years.
The study did have limitations, however, and despite the researchers’ attempts at weeding out other factors such as depression, age, social status and education, all know to decrease cognitive functions, the study is still observational.
This means that the cause-effect relationship is missing, instead the researchers only finding a link between the two.
Long term effects of daily marijuana use
The results were pretty much as expected, perhaps just slightly more favorable.
As it turns out, the only cognitive function affected by long term daily marijuana use was short term memory.
For every 5 marijuana years, the daily long term cannabis users remembered 0.5 fewer words from a 15 word list than the non-daily users.
Like I said, it’s more favorable than imagined.
The bad news, however, is that the effects stack; for every ten years, you will remember 1 fewer word, and so on.
The worst piece of bad news, however, is that the effects may be permanent. This hasn’t yet been confirmed, but it would look like the short term memory loss might not be treatable.
However, with the effects being so much lighter than expected, as well as with other narcotics like alcohol or cigarettes being far more destructive to the body and brain, the team behind the study doesn’t recommend going cold turkey.
Instead, they say that as with most things in life, moderation is key.
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