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The proper APA Style reference for this manuscript is:
LARRIEU, F. R. (2004). The Relationship Between Marijuana and Alcohol Use and Academic Performance in Undergraduate Students. National Undergraduate Research Clearinghouse, 7. Available online at http://www.webclearinghouse.net/volume/. Retrieved September 26, 2023 .

The Relationship Between Marijuana and Alcohol Use and Academic Performance in Undergraduate Students

Sponsored by: ELIZABETH HAMMER (eyhammer@loyno.edu)
This study was conducted to find the relationship between alcohol and marijuana usage in academic performance. The researchers hypothesized that there would be a negative relationship between the use of alcohol and academic performance and no relationship was expected between marijuana and academic performance. The study involved 121 undergraduate students filling out a 16- item questionnaire (see appendix) that contained questions about their lifestyle in regards to consumption of alcohol and marijuana, and study habits. Both alcohol and marijuana were found to be negatively correlated with GPA.

Throughout history, substance abuse has been the cause of many problems and tragedies, which has led it to be the topic of interest in several research studies such as the ones conducted by Finnell and Picou. More specifically, marijuana and alcohol have been the topic of many studies due to the fact that they are the most commonly used substances. For decades, marijuana use and heavy alcohol use have had negative connotations in society. Naturally, since it is illegal, marijuana has always been perceived more harmful than alcohol. To add to the negative connotation of marijuana, there have been many studies that imply that marijuana has a negative effect on a person’s abilities. For instance, a study conducted by Picou, suggests that marijuana use is positively correlated to the “amotivational syndrome”. People with the “amotivational syndrome” are less goal-oriented, and are characterized by a lack of motivation and lower levels of academic achievement (Picou, 1980,529). Another study found that, “adolescent drug use has been linked to lower indices of extracurricular activity, academic aspirations, and ‘attraction to’ school” (Evans & Skager, 1992, 354). Hence it is no surprise why many parents and educators are concerned that the academic performance of their children and students may be affected by the use of marijuana. However, maybe they should be more concerned about the effects of alcohol, as is suggested by Finnell’s research in which users of marijuana performed better on an aptitude test than users of alcohol (Finnell & Jones, 1975, 15). Of the many studies that have been conducted regarding the effects of marijuana and alcohol, none of them have found a strong correlation between the use of marijuana and alcohol and academic performance. Furthermore, more recent studies suggest that marijuana has no effect on academic performance. One such study found that there was no significant difference in the grade point average of students who used marijuana and those who did not use marijuana (Brill, 1982, 42). Due to the fact that the research in this field was conducted more than two decades ago and the contradictory findings of that research, an updated study is necessary to find a correlation between marijuana usage, alcohol usage, and academic performance. The hypothesis of this study is that there will be a negative correlation between alcohol use and academic performance, and contrary to the hypotheses of most previous research, that there will be no correlation between marijuana use and academic performance.


The participants of this research study were 100 undergraduate students. The researchers attended four introductory psychology classes to recruit participants and the study was posted on the psychology bulletin board so that any student could freely volunteer to be a part of the study. The subject pool consisted of both female and male students from several different nationalities.

The materials used in this study are very simple; first is a 16-item questionnaire created by the researchers. The first two questions focused on academic performance, defined by grade point average (GPA) in the previous semester as well as the cumulative GPA. The next three questions ask about the frequency of use of marijuana and alcohol within the last month and year. These are followed by a question on age and a question about year in school. Then there are nine questions that focus on the participant’s lifestyle. These include questions about one’s major, credit hours, study habits, class attendance, extracurricular activities, and the time spent in these activities. Additional materials include blank envelopes in which the participants can place their questionnaires when finished and informed consent forms, which inform the participants of the purpose of the study and alert them that they may withdraw from the study at any point.

This study implemented a correlational design. Several different subject variables were measured in this study such as age, major, currently enrolled credit hours, frequency of missed classes, time spent studying, time spent in extra-curricular activities, and most importantly, frequency of marijuana usage and frequency of alcohol usage. The dependent variable was academic performance, which was measured by the participants’ current and cumulative grade point averages.As the participants entered the room, each one was issued a copy of the questionnaire, an informed consent form, and a blank envelope. Each participant was then instructed to read the informed consent form and if they decided to continue taking part in the study to begin answering the questionnaire. Once they had finished answering the questionnaire, they were instructed to place it in the blank envelope and seal it. They were then told to keep the informed consent forms because they contained the telephone number they may call if they were affected negatively in any way throughout or after the study. Participants were then told the purpose of the study which was to find a correlation between alcohol and marijuana use and academic performance. To ensure confidentiality, all envelopes remained closed until the end of the study.

The overall direction of my research was guided by the question “how does marijuana and alcohol usage affect academic performance?” The mean cumulative GPA of the sample was 3.26 (SD=.51) and the mean consumption of marijuana was 5.8 (SD=8.61) times per month and 11.11 (SD=7.73) times per month for alcohol. Out of all drinking occasions, 54.86% (SD=35.64) of them were occasions in which participants drank excessively, (until drunk). The mean work load in terms of credit hours was 15.2 (SD=2.08) credit hours for which the participants of the sample studied an average of 9.27 (SD=5.90) hours per week. The participants skipped a mean of 3.55 (SD=3.63) classes and spent 12.19 (SD=10.21) hours involved in extracurricular activities. Statistical analysis of the data revealed a significant negative correlation between marijuana consumed per month and current GPA (r = -.27, p<.01) as well as between alcohol consumed per month and cumulative GPA (r = -.23, p<.05). The amount of credits being taken is negatively correlated with the amount of alcohol consumed per month (r = - .31, p<.01). The analysis also found a negative relationship between the amount of classes skipped and cumulative GPA (r = -.40, p<.01). In addition, amount of classes skipped is positively correlated with consumption of marijuana (r = .41, p<.01) and alcohol (r = .328, p<.01). The next part of the statistical analysis was a multiple regression in steps, with cumulative GPA as the dependent variable and alcohol consumed per month as the independent variable in the first step (â=-.234, p<.05). Then marijuana consumed per month was added in the second step, however, this did not significantly improve predictions (â=-.07, ÄR²= .004).

Prior to conducting the study, the researchers hypothesized that academic performance would be negatively correlated with amount of alcohol consumed per month. No relationship between consumption of marijuana and academic performance was expected. The hypothesis regarding alcohol consumption was supported by the data, however, a negative correlation was also found between consumption of marijuana and current GPA, contrary to expectations. However, multiple regression revealed an interesting result which was that marijuana use did not account for any additional significant variance in GPA, once alcohol use had been accounted for. It is no surprise that there is such a strong relationship between amount of marijuana consumed and amount of classes skipped. However, due to the fact that the relationship between alcohol consumption and classes skipped is only slightly weaker, the extent to which this is caused by the amotivational syndrome is blurred. Since both marijuana and alcohol are closely related to the amount of classes skipped, it is inconclusive whether this is due to alcohol usage or marijuana usage, and hence the amotivational syndrome. It is important to take into consideration that there are several limitations to this study such as the fact that all participants were undergraduate students and more specifically the fact that 57% of the participants were freshmen. This limitation has a tremendous effect on the validity of the study because the lifestyle of freshmen is very different than that of upperclassmen since they are in a new environment where they are forced to live on campus and in most cases they are living away from home for the first time. Another limitation is the fact that more than 80% of the participants were psychology majors. This might have had a negative effect on the results since it is possible that psychology majors may have a stronger or weaker affinity for marijuana and alcohol. These limitations make it virtually impossible to generalize these results to other populations of students especially since the lifestyle of high school students is so different. Further research should focus on the combined effects of marijuana and alcohol. The study should be conducted on high school students as well as undergraduate students. However, there should be a more even distribution of majors amongst the undergraduate students to ensure that no single major makes up the majority of the population because that skew the results.

Brill, N.Q. (1982). Psychological effects of marijuana use. American Journal of Social Psychology, 2, 41-44.Evans, W.P., & Skager, R. (1992). Academically successful drug users: An oxymoron? Journal of Drug Education, 22, 353-365.Finnell, W.S. (1975). Marijuana, alcohol, and academic performance. Journal of Drug Education, 5, 13-21.Picou, J.S., Wells, R.H., & Miranne, A.C. (1980). Marijuana use, occupational success values and materialistic orientations of university students: A research note. Adolescence, 15, 529-534.


1. What is your cumulative GPA?_________________

2. What was your GPA last semester?_________________

3. On average, how often have you smoked marijuana within the last year?_________________days per month__________________________________(other)

4. On average, how often have you drunk alcohol within the past year?_________________times per month__________________________________(other)

5. When you drink, how often do you drink excessively (until you are drunk)?_________________% of drinking occasions

6. What is your age?_________________

7. What year are you in college?A. FreshmanB. SophomoreC. JuniorD. Senior

8. What is your major?_________________

9. How many credit hours are you currently taking?_________________hours

10. How many credit hours did you take last semester?_________________hours

11. How many hours per week do you spend studying?_________________hours per week

12. How many classes do you skip in an average month?_________________classes per month

13. How many hours per week do you spend involved with school related organizations or events (SGA, BSU, Greek, etc.)?_________________hours per week14. What school related organizations or events are you involved in?_________________ __________________________________ __________________________________ __________________________________ _________________

15. How many hours per week do you spend involved with extracurricular activities (jobs, hobbies, etc.)?_________________hours per week

16. What extracurricular activities are you involved in?_________________ __________________________________ __________________________________ __________________________________ _________________

Submitted 5/10/2004 8:07:11 PM
Last Edited 5/10/2004 8:32:26 PM
Converted to New Site 03/09/2009

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