Cannabis+and+Adolescent+Brain+Development

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1. Background
Cannabis (“marijuana” or “weed” as it’s often referred) is a small plant who’s bud and leaves can cause a high to those who consume it. It has long been the source of controversy in the United States as many believe its effects are harmful while many others believe it to be rather beneficial. As research continues on the topic, there are an increasing number of reports that claim it to be extremely useful, particularly when it comes to pain relief and mental stabilization. In recent years, some states (most notably Colorado and Washington) around the country have began legalizing marijuana for not only medical use but also for recreational use which has opened the doors for many small vendors to sell weed to a wider variety of people. A recent studied showed that 16% of adolescents have tried marijuana by the time they reach the 8th grade which increases to 42% by the time they graduate high school (Bava). First use among adolescents is most common in young boys and most particularly those with antisocial behavior and those who experience less parental involvement in their day-to-day lives (Kosterman). As it becomes more apparent that the youth of today are gaining increasing access to this “drug” many are concerned that it can have drastic effects later in life. This only fuels the fire of acting out against marijuana consumption and particularly targets the idea of using marijuana as a method of mental stimulation treatment for young children and adolescents alike.

2. Adolescent Exposure
As mentioned upwards of 16% of adolescents begin consumption as early as 8th grade. This is the time-frame when puberty is moving full-speed ahead for most teenagers and is a time of crucial development for most parts of their bodies. Because of this, there is concern that the consumption of cannabis has effects on the child’s brain development and their ability to perform in school. In a study done by the University of California San Diego Department of Psychiatry, adolescents who regularly consumed marijuana were, under supervision, required to abstain from use for a total of four weeks. Despite the cleansing of their system, still performed more poorly on “tests of learning, cognitive flexibility, visual scanning, error commission and working memory” as compared to non-users indicating that marijuana may be a key factor in hindering cognitive abilities (Squeglia). However, in a similar study done by a team from Monash University in Australia who also had a test group maintain a longer period of abstinence, noticed some different results. Adolescents can in fact fully recover from any cognitive deficits given a long enough period of non-use (Lubman). So while cannabis can be linked to impairing the young mind and its ability to perform, there is still evidence to show that it is by no means a lasting effect.

i. Effects on Cognitive Ability
A group of frequently marijuana consuming boys (ages 13-19) was compared to a group of non-using peers measuring the memory capabilities of their brains. There are multiple types of memory systems at work in the brain, one of which is called “working memory.” This is the part of one’s short-term memory that is responsible for immediate and conscious processing of one’s surroundings. When compared to one another, it was revealed that users exhibited an overactive working memory system (compared to the non-users) when completing novel tasks which correlates to the brain trying to work harder to process everything going on. This indicates that frequent marijuana use impaired their ability to efficiently engage in unfamiliar tasks without struggle (Jager). A study done at the University of Colorado Health Sciences Center that constituted 55 middle-aged “chronic users” who had been using since adolescence revealed that 44% had structural brain damages. These damages were most prominent in white matter (tissue of the brain) abnormalities (lack of maturation for the most part) which causes greater cognitive impairment (Lubman). Along these lines of greater cognitive impairment, there have also been studies conducted over longer periods of time that gauge the intelligence quotient (IQ) of a person who began consumption as a teenager and continued to consume well into their 30s. The subjects displayed on average a drop of about 6 IQ points as a result of the marijuana consumption. To ensure that this was not just a result of marijuana use in general, adult-onset marijuana users (those who didn’t begin consumption until their adult years) showed little to no variation in IQ over the same window of time as the adolescent-onset users (Meier).

**ii. Physical Changes of the Brain** As adolescence is the point in a human’s life in which one’s body undergoes dramatic changes both physically and mentally, the brain undergoes a “critical period of neurodevelopment” in areas such as the frontal cortex (Bossong). Despite many tests indicating clear differences in cognitive abilities of long-term users, there are not many indications of actual physical changes to the structure of the brain itself. A study at the university of Iowa analyzing adolescents over the course of a few years saw little to no differences in the volume growth of the frontal, temporal, parietal, and occipital lobes as compared to the control group (Block).

4. What can be learned
While marijuana itself is of no real danger to the user unlike other narcotics, it still has lasting effects on those who consume regularly regardless of age. As an adolescent going through major physical and sensitive transitions in ones life, these effects can be amplified much more dramatically than in someone who begins using as an adult. Use of cannabis has been shown through numerous studies to hinder one’s ability to perform as efficiently as a non-user when it comes to basic tasks, and it can also noticeably impair one’s learning ability. Fortunately, other studies have also shown that abstinence does in fact aid in recovering the brain even if one was a frequent user at a young age. The brain can regain complete control of itself and no longer be affected by use as an adolescent. However, abstinence only allows recovery in the control aspect of the brain. As mentioned above, the brain undergoes some physical changes if used frequently, and these changes can not be reversed. All in all, cannabis is not a harmful drug regardless of age of use. But harmless does not mean it comes without consequences. It may be safe to use, but there are affects that can stick around for one’s entire life.

5. References (MLA)
1. Bava, Sunita, and Susan F. Tapert. "Adolescent brain development and the risk for alcohol and other drug problems." Neuropsychology review 20.4 (2010): 398-413.

9. Block, Robert I., et al. "Effects of frequent marijuana use on brain tissue volume and composition." NEUROREPORT-OXFORD- 11.3 (2000): 491-497.

8. Bossong, Matthijs G., and Raymond JM Niesink. "Adolescent brain maturation, the endogenous cannabinoid system and the neurobiology of cannabis-induced schizophrenia." Progress in neurobiology 92.3 (2010): 370-385.

5. Jager, Gerry, et al. "Cannabis use and memory brain function in adolescent boys: a cross-sectional multicenter functional magnetic resonance imaging study." Journal of the American Academy of Child & Adolescent Psychiatry49.6 (2010): 561-572.

10. Jager, Gerry, and Nick F. Ramsey. "Long-term consequences of adolescent cannabis exposure on the development of cognition, brain structure and function: an overview of animal and human research." Current drug abuse reviews 1.2 (2008): 114- 123.

2. Kosterman, Rick, et al. "The dynamics of alcohol and marijuana initiation: patterns and predictors of first use in adolescence." American Journal of Public Health 90.3 (2000): 360.

4. Lubman, Dan I., Ali Cheetham, and Murat Yücel. "Cannabis and adolescent brain development." Pharmacology & therapeutics 148 (2015): 1-16.

6. Lubman, Dan I., Murat Yücel, and Wayne D. Hall. "Substance use and the adolescent brain: A toxic combination?." Journal of Psychopharmacology21.8 (2007): 792-794.

7. Meier, Madeline H., et al. "Persistent cannabis users show neuropsychological decline from childhood to midlife." Proceedings of the National Academy of Sciences 109.40 (2012): E2657-E2664.

3. Squeglia, Lindsay M., Joanna Jacobus, and Susan F. Tapert. "The influence of substance use on adolescent brain development." Clinical EEG and neuroscience 40.1 (2009): 31-38.