2008-09 Gathering of Voices

Marijuana and Academic Achievement: A Case Study

Marta Unterschute


Marijuana, central to some of the most controversial issues of the 21st century, has been highly debated for years. Thousands of studies regarding the drug have been conducted with most leading to insufficient evidence. Some studies point to memory deficit but reliable results are inhibited by variables not taken into account during research. Certain studies infer this substance lowers motivation and long term memory resulting in poor grades and academic achievement (2). Accurate knowledge of the effects of marijuana is important in determining whether or not cannabis negatively interferes with the academic achievement of students. This could include information about short term effects while inebriated and long term effects involving temporary and permanent cognitive and behavioral changes. This evidence may be used to benefit students who find themselves struggling to maintain grade point averages by depicting the effect of marijuana on their studying habits or mental abilities.

Cannabis, a fragrant, leafy plant found typically in temperate regions has been found to have multiple purposes. This specie’s fibers are ideal for making material such as rope and clothing (3). In 2737 B.C., Emperor Shen Neng first discovered its medical qualities. This substance was prescribed for ailments such as gout and malaria. It diffused to other countries such as India which thought it to be a “holy plant” because of its calming effects. Cannabis finally made its way to America and was reported to be first used in 1764 (2). However, its medicinal properties were finally popularized in the early 1900’s. Marijuana has not only been used for medicinal or religious purposes, it has also been used socially and recreationally. Currently, 200-300 million people worldwide have reported cannabis use (2). Historically, this herb was common in the United States amongst minority groups like Mexicans and African Americans. The public soon associated marijuana criminal activities and began gaining a bad reputation for inducing violence and sex cravings. In an effort to control this substance, the U.S. government imposed the Marijuana Tax Act of 1937 which heavily taxed the growth and distribution rendering it essentially illegal. It was eventually classified as a Schedule I narcotic meaning it has no medicinal value (8). Cannabis has been studied, researched and debated ever since regarding its long and short term effects and whether or not it truly has medicinal purposes.

The main chemical in Cannabis, delta-9-tetrahydrocannabinol or THC, is said to give a calming, sometimes euphoric, effect. Upon inhalation the, “THC is rapidly absorbed into the blood and distributed first to the brain, then redistributed to the rest of the body” (8). The chemical is drawn to two receptors: CB1 and CB2. CB1 receptors are found in the brain while CB2 receptors are found in the immune cells. These receptors are located in the cerebellum, hippocampus, cerebral cortex and the nucleus accumbens which control the “coordination of fine body movements”, “memory storage”, “higher cognitive functioning” and “reward system” (8). This helps explain certain reported effects such as forgetfulness and decreased vigilance (2).

While under the influence of marijuana, side effects may include the slowing of time, enhanced senses, euphoria, relaxation, stronger feelings, increased focus on present, forgetfulness, slower reaction time and impaired concentration. At higher doses, negative effects such as increased fear, anxiety, paranoia, and sleep impairment may occur. Intoxication demonstrates “problems concentrating, attending to details, focusing on goals, performing two actions simultaneously, and learning new, complex information” (2). These effects vary based on the quantity smoked, length of inhalation, potency of strain and tolerance of the individual (2). Marijuana intoxication is also said to have profound effects on learning which may result in poor academic achievement.

The key to understanding cannabis’s cognitive effects is studying the long term damages of chronic exposure. Certain experiments in the United States “show no effects of fairly heavy marijuana use on learning perception or motivation over periods as long as a year” (4). Many studies have been conducted surrounding the long term effects of marijuana but accurate results are challenging to ascertain. One particular study tested seventy people ages 17-23 with their known IQ before cannabis use. The participants who smoked five or more joints per week had a decreased IQ of 4 points, although participants who had previously been heavy users but had ceased use were not observed to have a negative effect on their IQ. This study showed that there were no conclusive results demonstrating “long-term daily consumption results in persistent cognitive impairment after cessation of use” (11). Various other studies suggest that “chronic exposure to cannabis may change cognition” and that long term users “appear to process information less quickly and efficiently” (2). A study conducted by Murat Yucel from the University of Melbourne compared hippocampus size of heavy users who smoked five joints a day for twenty years and nonusers. The hippocampus which controls memory and emotion had a 12% smaller volume in heavy users than in nonusers (1). Heavy users have also reported having “deviant brain waves when performing certain complex tasks” (2). Two experiments conducted in 1987 and 1988 hinted at the possible long term side effects of heavy use. Rats were given a quantity of marijuana, equivalent to a heavy user, each day for 90 days. This gave evidence of “permanent changes in the structure of neurons in the hippocampus” (8). Although there is evidence hinting at potential long term damages, “chronic marijuana consumption does not appear to create gross neuropsychological impairments” and only lead to “deficits on highly sensitive tests” (2). This, however, does not include damages from early exposure to marijuana. A study was conducted on users who began use before the age of 17 compared to users who began after the age of 17. The early users were reported to have lower verbal IQs (11). This suggests that early marijuana use during brain development may have negative cognitive effects.

One significant question regarding its cognitive effects is the relationship between marijuana usage and academic achievement. Cannabis’s negative reputation of “dumbing” down a person could result in such occurrences as poor grades or low academic achievement. There is “considerable data showing that marijuana use is associated with poor school performance, low grades, less satisfaction with school, worse attitudes toward school and poorer school attendance” (11). This correlation, however, is unclear whether it is the cause of the marijuana itself or the characteristics and behaviors of the individual. Studies conducted have very little experimental control. Some alternative explanations may be that “poor adjustment in work or school might lead some people to use cannabis” or “depressed people might perform poorly and choose to use cannabis” (2). Judging whether cannabis is the sole cause is a difficult task. Some other contributing factors may be poly-drug use or influence from peers. Many cannabis users experiment with other drugs as well; any of these other drugs may be an additional reason for poor academic achievement. Indirect influence from deviant peers may also contribute to diminishing scholarly goals. Characteristic approaches are reinforced by some experiments. One researcher conducted a survey of 1400 undergraduates. The survey showed no difference in the grades of the users and non users, although it did reveal that users “took more time off from their schooling but were also more likely to plan to earn a graduate degree” (2). The different level of education may help demonstrate that marijuana effects each individual differently and that marijuana may not be the cause for low education or low motivation levels.

Certain research demonstrates “that the earlier the use the more likely the student will not complete high school” (11). When users manage to obtain the motivation to complete high school, how their grades in college are affected is of some importance. Research has show that high school marijuana smokers tend to spend less time completing school related material and as a result have lower grades and drop out. Though low grades is correlated with marijuana usage, chronic users tend to have low academic achievement before initiation to marijuana. “Marijuana does not create uninterest in school, rather the kid is uninterested and turn towards marijuana” (2). Would such students be found in institutions of higher education? A longitudinal study conducted by William Jeynes observes the effects of drug usage and academic achievement of about 19, 000 students. He describes circumstances of some students coming to class under the influence. This type of behavior typically has a poor effect on ones achievement in school. “The effects for being under the influence of marijuana while at school were larger in absolute value than the effects that resulted from consuming marijuana at higher levels during the course of one’s lifetime” (7). This begins to describe the difference between use and misuse. Students who chose to be high during class may have a lack the commitment for their schooling which may result in the “low grades” and “low satisfaction” of school. “Being under the influence of drugs while at school probably indicates that a given adolescent has a problem controlling his or her intake of drugs” (7).

The amount of use resulting in abuse is relative amongst all marijuana smokers. “Regular use of cannabis can lead to psychological habituation for some people making it difficult for them to quit” (3). One characteristic of abuse is having one’s daily life; school, family, and/or work, interfered with because of misuse. However, some users manage to “arrange their lives to minimize the impact of their drug use on obligations” (2) and habitual users may have the ability to prioritize and balance their school work and their usage. It may not be the marijuana that deters academic achievement but the motivation and care of any given student. Although this ability is not common amongst all marijuana users, “most important to consider, is the fact that excessive drug consumption is rarely a ‘primary cause’, but rather results from other factors that are active in a person’s life” (7). These other factors may also aid in poor academic achievement.

There are many approaches that attempt to explain the loss in need for achievement. Although there is an exponential amount of research that demonstrates a correlation between marijuana smoking and decreased motivation, it is difficult to prove cannabis as being the sole cause of the syndrome. The enormity of other potential variables for things like decreased motivation results in inconclusive evidence. To begin to come to a conclusion about the effects of marijuana, more controlled experiments which look at and discuss other factors such as background family life, personality, poly drug use and peer influence need to be conducted. Until sufficient experiments are conducted, researchers will have to depend on the increased amounts of data regarding this substance.


The amount of marijuana smoked by college students tends to affect the grade point average of that individual.


The methodology used was a case study. To do library research the researcher searched Whatcom Community College’s library catalog with the key word “Marijuana” and found two books, Marijuana: Opposing Viewpoints and Understanding Marijuana: A New Look at the Scientific Evidence. Inside Marijuana: Opposing Viewpoints the researcher found two articles entitled “Marijuana is Harmful” and “Substance Abuse: A Comprehensive.” Then through Proquest the researcher used the key words “Marijuana and Academic Achievement” and found “The Relationship Between the Consumption of Various Drugs by Adolescents and their Academic Achievement” by William H. Jeynes. The researcher then used Google and the key words “Social Research, Marijuana Use, GPA” to find “Deterioration of Academic Achievement and Marijuana use Onset among Rural Adolescents” by Kimberly Henry, Edward Smith and Linda Caldwell. Using Google as well, the researcher used the key words “social research, marijuana use, college student, and academic achievement” to find the article “Marihuana Use and Achievement Orientations of College” by Alfred C. Miranne. From previous knowledge the researcher found the site Erowid which had the article “Marijuana.” The researcher’s sister also referred them to the text book Drugs, Society, and Human Behavior by Charles Ksir, Carl Hart, and Oakley Ray. The research was collected between September 24, 2008 and October 31, 2008. The researcher focused their research to college students at Whatcom Community College. A total of 30 surveys were handed out. To obtain random, unbiased results the researcher stood at different building’s entrances (Syre Center, Kulshan Building and Cascade Hall) and asked every second individual person who was not already preoccupied by such devices as an IPod or cell phone to participate in the survey. The researcher switched the location of their inquisition as to ensure all types of people had a chance to participate. The researcher asked every second person to ensure that they did not ask people they may be bias towards or against. The researcher also refrained from asking people in groups or with others to ensure no peer-influenced results. Included below is the survey used to conduct the researcher’s case study.


Marijuana Usage in College Students



  1. What year in college are you?
    a. Freshman b. Sophomore c. Junior d. Senior e. Other:_____________
  2. How old were you when you first tried marijuana? (If never skip to question 10) __________
  3. How many years have you smoked marijuana?
    a. 0-6 months b. more than 6 months - 1 year c. more than 1 year - 2 years
    d. 3 - 4 years e. 5-6 years f. 7+ years
  4. How often do you smoke a week? (If daily answer question 5) _____________________
  5. How many times a day do you smoke?
    a. 1-2 times b. 3-4 times c. 5-6 times d. 6+ times
  6. Who do you typically smoke with (do not provide names, just relationship ex: friends, siblings, classmates, coworkers, etc.)?_________________________
  7. Do you ever go to class under the influence of marijuana?
    a. Never b. Sometimes c. Often
  8. Do you study under the influence of marijuana?
    a. Never b. Sometimes c. Often
  9. Have you ever studied under the influence of marijuana?
    a. Yes b. No
  10. Do you smoke cigarettes?
    a. Never b. Sometimes c. Often
  11. Do you drink coffee?
    a. Never b. Sometimes c. Often
  12. Do you drink alcohol? (If never skip to question 14)
    a. Never b. Sometimes c. Often
  13. How often do you drink a month?
    a. 1-2 times b. 3-4 times c. 5-6 times d. 6+ times
  14. Do you use or have you ever used any other recreational drugs?
    (If no, skip to question 17)
    a. Yes b. No
  15. Circle all that apply.
    1. Opiates (Oxycoton, Oxycodone, Heroine etc.)
    2.  Pharmaceuticals (Valium, Xanax, Vicodin, Adderall etc. Any prescribed medicine that is not prescribed to you or any of your prescriptions that you did not use as the doctor recommended)
    3. Hallucinogens (LSD, Mushrooms, 2c-i etc.)
    4. Club Drugs (MDMA (ecstasy), Ketamine etc.)
    5. Stimulants (Methamphetamine, Cocaine etc.)
    6. Inhalants (Nitrous Oxide, Glue, Gasoline etc.)
    7. Other:______________________________
  16. How often do you use these drugs?
    a. Never b. Sometimes c. Often
  17. What is your grade point average?
    a. 4.0-3.5 b. 3.4-3.0 c. 2.9-2.5 d. 2.4-2.0 e. Below 2.0
  18. What is your average grade in math courses?
    a. A b. B c. C d. D e. E
  19. What is your average grade in science courses?
    a. A b. B c. C d. D e. E
  20. Do you feel you are able to balance smoking marijuana and school work?
    a. Always b. Often c. Sometimes d. Never
  21. Do you feel smoking marijuana prevents you from doing your best at school?
    a. Always b. Often c. Sometimes d. Never
  22. Have you ever thought quitting marijuana may help improve your grades?
    a. Often b. Sometimes c. Never


Results and Analysis

 The results were surprising. The hypothesis stated that marijuana tends to affect the grade point average of college students. However, the results were spread out; there were many high, middle and low grade point averages of both users and nonusers although there were a remarkable number of high grade point averages for users, especially heavy users. Light user was defined as smoking marijuana less than four times a month. An intermediate user was defined as smoking marijuana two to four times a week. A heavy user was defined as smoking five or more times a week. This graph demonstrates that there is a relatively equal amount of non, light, intermediate and heavy users who receive between a 4.0 and a 3.5. The majority of heavy users, however, receive between a 3.4 and a 3.0, whereas the majority of nonusers receive between a 2.9 and 2.5. The light users are relatively evenly dispersed between the grade point averages. This evidence is inconclusive. Although there may be evidence of partial impairment of the heavy users, there are some, however, that manage to receive high marks. The high number of nonusers who receive lower grades demonstrates that there may be a different variable playing into academic achievement besides marijuana usage. A study touched upon by Mitch Earlywine depicted evidence that showed marijuana users receiving higher marks than nonusers. This, however, does not prove marijuana helps grade point averages but rather demonstrates the multitude of other potential variables, possibly other drug or alcohol consumption, lack of motivation or family problems.

The number of years individuals have used marijuana is also significant. A beginner was defined as having started smoking less than one year ago. A novice was defined as having been smoking for one to two years and an experienced user was defined as having been smoking for three or more years. It appears that the majority of marijuana smokers who attend college have tried marijuana three years prior to this survey. Although the novice and beginning users appear to not have any dramatic affects on the grade point averages of the individuals, the results for experienced users are dramatic. It appears that experienced users are able to fully function in school and, although some of these people may have been past users and have since quit, it demonstrates that the previous marijuana usage does not significantly affect their academic achievement. Earlywine describes this pattern as users finding ways to “arrange their lives to minimize the impact of their drug use on obligations” (41). In this particular case, the obligation is school. This may help describe that if the motivation is present, marijuana may not be a significant inhibitor.

 The next resulting question is whether the users attend class or study under the influence of marijuana. This is relevant because of previous studies that have found problems with learning new information while under the influence. THC, according to “Drugs, Society and Human Behavior”, effects particular parts of the brain which may result in a subject’s forgetfulness increases while reaction time, concentration, certain aspects of memory, ability to learn complex information, and simultaneously performing two actions decreases. These side effects can greatly affect a subject’s ability to retain information given during class or studying. The survey offered three options in attending class or studying under the influence: often, sometimes or never. None of the respondents selected the “often” option. This may be evidence of bias of the respondents, who may not want to admit to themselves they study or go to class under the influence too much. Although many users sometimes study under the influence and it appears that they attend class under the influence less often, their grades are generally unaffected. This could, however, be a problem for some and not others.
Studying or attending class under the influence may be detrimental to the academic achievement of students with a 2.9 or below. Although many respondents sometimes study and attend class under the influence and receive high marks, this does not mean that marijuana does not prevent them from doing their very best but it may limit them in an insignificant quality. Heavy marijuana users may have also found ways to allow continued marijuana use and studying to coexist. After attending class under the influence, a subject may look over notes when they are no longer under the influence which may help enforce the material in their mind. It has been noted by Earlywine that although marijuana affects memory, it does not affect all aspects of memory and has actually been said to sometimes enhance recall memory. If a subject studies previously learned material while under the influence this may have little effect on their studying.

To ensure other variables are looked at, the researcher also asked questions on alcohol and poly-drug use, as these may be potential reasons for lower academic achievement. A light alcohol user was defined as drinking one to two times a month. An intermediate alcohol user was defined as to drink three to four times a month. A heavy alcohol user is defined to drink five or more times a month. A light poly-drug user is defined as to have used one to two different types of drugs. An intermediate poly-drug user is said to have used three to four types of drugs and a heavy poly-drug user is said to have used five or more different types of drugs. It seems that high academic achievers are able to balance light alcohol usage and their grades. Several heavy alcohol users are able to balance their usage with their grades but an equal number of heavy users are found to have low academic achievement. Alcohol use could be one explanation for the low academic achievement in non-marijuana users. Alcohol is profoundly more common than poly-drug usage (perhaps because of legality reasons).
Many non poly-drug users maintain high levels of academic achievement and, although the number of heavy and intermediate poly-drug users is limited, the level of academic achievement is widely dispersed. A National Educational Longitudinal Survey studied students, their drug usage and their academic achievement. William H. Jeynes studied about 19,000 students and concluded that “adolescents consuming [poly-drugs] might simply be replacing one compulsive/excessive behavior with excessive drug consumption. And indeed the prior compulsive/excessive behavior may also impact academic achievement” (14). He continues to explain that “most important to consider, is the fact that excessive drug consumption is rarely a “primary cause”, but rather results from other factors that are active in a person’s life” (15). These other factors in a person’s life, such as family issues can also be a contributing cause to low academic achievement. This may explain the varying academic achievement for heavy alcohol and heavy poly-drug usage.

To conclude the survey, the researcher asked the questions, “Do you feel you are able to balance smoking marijuana and school work”, “Do you feel smoking marijuana prevents you from doing your best at school”, and “Have you ever thought quitting marijuana may help improve your grades”. These questions were designed to see what the smokers themselves feel about their usage and whether they are able to manage smoking and their school work. When asking respondents whether they feel they can balance smoking marijuana and school work the majority of users feel that they can always balance their usage and school work, although there are five heavy users who are less confident in that ability. This again touches upon use and misuse. As Mitch Earlywine describes, the “first symptom of abuse, interference with major obligations requires impaired performance at work or home or school” (41). To continue explaining this “interference”, respondents were questioned whether they think marijuana prevents them from doing their best at school. The majority of light users feel that their usage does not prevent them from doing their best at school. Intermediate users typically feel that marijuana sometimes prevents them from doing their best at school while heavy users have mixed opinions on how much marijuana usage prevents them from doing their best although the majority are skewed towards thinking that it sometimes or often prevents them from doing their best. Most light and intermediate users never thought that quitting marijuana may help improve their grades. This was significantly different than the heavy user response that think sometimes and often that quitting may help improve their grades. This could be an indicator that heavy users know and understand the cognitive impairments marijuana may cause them when trying to focus on school.

There are, however, a number of short comings and biases to this survey which could potentially skew results. For some, it may be difficult to remember the exact time when they first tried marijuana which could interfere with whether they are a beginner, novice or experienced user. The amount smoked may also be inaccurate, the subject may have accidentally guessed incorrectly, have guessed over their average to “seem cool” or guessed under their average to make themselves feel like less of an addict. This same problem could have occurred regarding their responses to whether they study or go to class under the influence. Some people may be biased against themselves and want to seem cool or make themselves feel better by thinking that they do not study or attend class under the influence. The same occurrence could have happened with alcohol and poly drug usage, some may over exaggerate to seem cool and some may under exaggerate to make themselves feel better, while others may have simply forgotten. Judging the grade point average of an individual may be difficult to determine as well, some may lie to make them feel better about themselves and some may be between two averages and guess their grade to be higher than it actually is. Another shortcoming of the survey is the last three questions, these are all centered on opinion and generally a human beings view of oneself is different from the reality of their situation. Some may have also not understood the questions entirely, or felt that the answers provided may not adequately depict their situation, resulting in skewed answers.

Overall the researcher’s results were null. Both nonusers and users academic scores were spread out throughout 4.0 to 2.0. Although there were many 4.0-3.5 marijuana users, there seemed to be no real pattern of the amount of marijuana smoked and the grade point average of those individuals. Many users felt that quitting marijuana may help improve their grades, whether there would be a significant change in their grade point average if they decided to quit is still questionable.

Heavy drug users in our society are often bored, depressed, and listless or alienated, cynical and rebellious. Sometimes the drugs cause these states of mind and sometimes they result from personality characteristics that lead to drug abuse. (Grinspoon, Bakalar, and Russo 31)

It seems that from users to nonusers, grade point average is not dependent on drug abuse alone but rather a number of other variables. These variables may include their original IQ, level of motivation and interest in school, family situation, values taught as a child, having a job or psychological health. Marijuana and other drug usage is typically correlated to low grades but as we can see from certain poly-drug, heavy marijuana and heavy alcohol users who obtain high grades that it is not the only cause of low academic achievement. Earlywine elucidates that use is “common among low grades but not the sole cause of low grades.” (55)

To further study the relationship between marijuana and academic achievement a more in-depth study is suggested. Gathering qualitative data regarding people who smoke marijuana and struggle with academic achievement and people who smoke marijuana and do not struggle with academic achievement may assist in better understanding other potential causes. When studying these subjects a researcher should look at the amount, how often and how long a subject has smoked, race, family, socioeconomic background, the way a respondent was raised as a child, what values were taught, personality traits of the individual, studying habits, people they socialize and associate with and whether or not they have a job. All of these factors could effectively reduce academic achievement. Exploring the relationship and the interaction of these variables could also be key to understanding how some manage high academic achievement and how others do not. Also comparing the similarities and differences of high academic achievers and low academic achievers may also show which variables are necessary for high academic achievement. Overall, more research is needed to better understand the relationship between marijuana and academic achievement.


  1. Dunham, Will. "Heavy marijuana use shrinks brain parts: study." Reuters. 02 June 2008. Thomson Reuters. 4 Nov 2008 <http://www.reuters.com/article/scienceNews/idUSN0227147420080602?
  2. Earleywine, Mitch. Understanding Marijuana: A New Look at the Scientific Evidence. Oxford University Press, 2002.
  3. Erowid. "Cannabis Basics." Erowid.org. 3 November 2008 <http://www.erowid.org/article_url.shtml>.
  4. Grinspoon, Lester, Bakalar, James B., and Russo, Ethan. Substance Abuse: A Comprehensive Textbook. Philadelphia: Lippincott, Williams & Wilkins, 2004.
  5. Henry, Kimberly L., Smith, Edward A., and Caldwell, Linda L.. "Deterioration of Academic Achievement and Marijuana Onset Among Rural Adolescents." Oxford Journals Medicine 22(2007): 372-384.
  6. Jamuna, Carroll. Marijuana: Opposing Viewpoints. Detroit, Mi: Greenhaven Press, 2006
  7. Jeynes, William H.. "The Relationship Between The Consumption of Various Drugs by Adolescents and Their Acadenuc Achievement." The American Journal of Drug and Alcohol Abuse 28(2002): 15.
  8. Ksir, Charles, Hart, Carl L., and Ray, Oakley. Drugs, Society, and Human Behavior. 12th ed. New York: McGraw-Hill, 2008.
  9. "Marijuana Timeline in the United States." Marijuana. PBS. 4 Nov 2008 <http://www.a1b2c3.com/drugs/mj005.htm>.
  10. Miranne, Alfred C.. "Marihuana Use and Achievement Orientations of College Students." Journal of Health and Social Behavior 20(1979): 194-199.
  11. Rey, Joseph M., Martin, Andres, and Krabman, Peter. "Marijuana Use Is Harmful." Journal of the American Academy of Child and Adolescent Psychiatry 43(2004): 1, 194.


*The number associated with each citation is congruent to the citation in case study.

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