Marijuana’s Effects on Cognitive Ability Marijuana is the most widely used drug in America. In recent years, the debate over its use has become very polarized with results in various studies showing benefits in certain specific cases and detriments in others. Virtually all research regarding cognitive ability concludes with detrimental outcomes.
Recent studies directed toward measuring short term cognitive effects of marijuana use show considerable deficits among adolescents in areas like verbal learning, verbal working memory, and attention accuracy. While the negative cognitive effects of marijuana use are easily characterized as short term, most studies do not follow subjects for long enough to measure the long term effects. Cognitive ability does improve after marijuana is no longer being used, but those short term deficits are likely to carry over throughout the user’s life.
Short term cognitive losses are the result of a part of the brain called the hippocampus being damaged. The hippocampus is largely responsible for memory storage. The hippocampus is a small region of the brain that forms part of the limbic system and is primarily associated with memory and spatial navigation. Let’s take a bird’s ability to find nuts it hides months after it places them in crevices in trees. During autumn and winter, many birds hippocampus actually increases in size to assist in retrieving hidden nuts through enhanced memory storage. If a bird were to use marijuana when storing nuts for winter, its hippocampus would likely be damaged to the extent it would be less successful in retrieving those hidden nuts. Humans obviously don’t need to store and find nuts months later, but we do need to remember a vast amount of information and be able to retrieve that information throughout our life. The health of our hippocampus plays a big part in our cognitive ability, and marijuana use shows no signs of improving that ability.
