The Relationship Between Marijuana and Alcohol Use and Academic Performance in Undergraduate Student
Sponsored by Missouri Western State University Sponsored by a grant from the National Science Foundation DUE-97-51113
Home |
The proper APA Style reference for this manuscript is:
HALLINAN, T. M. (2004). The Relationship Between Marijuana and Alcohol Use and Academic Performance in Undergraduate Student. National Undergraduate Research Clearinghouse, 7. Available online at Retrieved April 25, 2017 .

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

Sponsored by: ELIZABETH HAMMER (
The relationship between marijuana and alcohol use and academic performance was investigated. The participants were 121 Loyola University New Orleans undergraduate students recruited from psychology courses and from a posted sign up sheet. Marijuana and alcohol use were determined by a series of questions included in a survey answered by the participants. Grade point average was the measurement used for academic performance. The hypotheses were that there would be a positive correlation between marijuana use and academic performance and that there would be a negative correlation between alcohol use and academic performance. Upon analysis of the data, it was originally discovered that both marijuana and alcohol use have negative correlations with academic performance. Past research in this area both supports and rejects the findings of this study as studies in the past had conflicting findings amongst themselves.

It has been widely accepted in modern times that college is a time to learn, experiment, and grow. Academic performance is the commonly used gauge with which to determine whether or not a student has indeed learned what he has been taught. Through testing and assignments, the student proves to his professor that he has absorbed the material given to him. The level to which the student has understood the material is given in the form of the grade, which in combination with the rest of the student’s classes determines his grade point average. In theory, the grade point average is a reflection of how much the student learned during his time in college. All in all, the purpose of college is to prepare the students with the knowledge and skills to pursue a career or continue with their education. Creating an optimal state in which a student is best able to learn and implement the knowledge he has been taught is of interest to both the student and his professor. The student desires this optimal state, as it will more than likely result in a higher level of academic performance. The professor is interested in the education of her students and hopefully would be interested in the students’ ability to adequately absorb this education. This study focuses on marijuana and alcohol usage; past research on this subject suggests that there is a correlation between these two variables and academic performance operationally defined as grade point average. A possible correlation between the usage of the two substances and academic performance therefore becomes interesting to both the student and the professor, as the implications may help both groups understand the effects these substances might have on the possible fulfillment of college objectives and academic success. The past research mentioned is both interesting and conflicting at times. There were numerous studies done during the 1970s as the use of marijuana had continued to increase through the late 1960s. A study by Goode (1971) found that students who had experimented with marijuana once or more and students that had never used marijuana had nearly identical grade point averages. Further, he discovered that casual and infrequent users earned the highest grades and the heavy users earned the lowest grades; the breaking point at which marijuana use began to decrease academic performance was when the student smoked marijuana more than once a week. Strangely the students that totally abstained from marijuana use had only slightly higher grades then the heavy users. A study by Gergen, Gergen, and Morse (1972) had similar results. They found that the students with an “A” average were the most experienced marijuana users and also “that it is generally the better students in the nation who are more prone to use the drug” (Gergen et al., 1972, p. 8). The researchers also note that it cannot be concluded that marijuana does not hinder the students’ academic performance since their grades prior to their marijuana usage were unavailable. This is an obvious limitation to the study, and to our current study, as only the correlations between marijuana use and academic performance can be recognized; only an experimental design could show whether or not the drug is hindering student’s academic performance. Other studies, while not rejecting the conclusions drawn from these previous studies, could not confirm a positive relationship. Brill (1982) conducted a longitudinal study at UCLA in which he found results that were also congruent with the other research studies. He found that the great majority of students “who had used marijuana reported no adverse effect on their academic performance” (Brill, 1982, p. 41). He further found that there was no significant difference between the grade point averages of users and nonusers, though previous studies had indeed found some significance.. Finnell and Jones (1975) conducted a study using grade point average and composite ACT scores as their operational definition for academic performance, while also including alcohol use as another variable. They found that students who used both marijuana and alcohol reported the highest ACT scores, followed by the students who used marijuana alone, followed by students who used alcohol alone. Students who abstained from using either substance reported the lowest scores. In terms of grade point average, they again found that students who used both alcohol and marijuana had the highest cumulative grade point averages; strangely, the students who used marijuana alone were ranked last. This is contrary to the implications of the previously mentioned studies that suggested that marijuana use had a positive correlation with academic performance. It also raises an interesting point: Why do the students who drink alcohol and smoke marijuana have a higher cumulative grade point averages then the students who smoke marijuana but do not drink? Is there an interaction between the alcohol and marijuana use that was not evident in other studies? A study by Pullen (1994) on alcohol use and college students found a positive relationship between alcohol use and grade point average, but did not consider marijuana use. The positive relationship found in this study combined with the idea raised in Finnell and Jones’(1975) study (the interaction between the variables themselves) suggests that alcohol use might have a stronger relationship with grade point average then marijuana use. Pullen’s (1994) study was contradicted an earlier study by Picou, Wells, and Miranne (1980), which found that frequency of alcohol use was negatively associated with grade point average. In the same study, they found that marijuana use was positively related to grade point average. Again, a contradiction between studies, drawning attention to the possibility of errors in validity with previous research. With the relationship between the variables themselves being questioned, it becomes difficult to attempt to explain any of these previously noted correlations. Considering this past research and the dubious implications presented by the individual studies, this study was created by the researchers with the purpose to find a relationship between marijuana and alcohol use and academic performance among undergraduate colleges students using a survey with operationally defined terms. Though similar in procedure to many of the studies mentioned previously, the population from which it is being drawn, Loyola University New Orleans undergraduate students, the survey being used, and the time period in which the study is being conducted differ from research done in the past. The contradictions and implications of previous research have been considered and blended within this study, hopefully helping it to move a bit beyond what has been done already. Because of this past research, the hypotheses were easily constructed with educated awareness. It is hypothesized that marijuana use will have a positive relationship with academic performance while it is also hypothesized that alcohol use will have a negative relationship with academic performance.


The study consisted of 121 undergraduate students at Loyola University New Orleans. Students’ rank varied from freshmen to seniors and their ages varied from 18 to 22 years. Both males and females were included in the study. Students either signed up for times to have the survey administered on a signup sheet posted on the psychology bulletin board or were recruited in various meetings of different student organizations.

Researchers will provide writing instruments (if needed), surveys (entitled “Survey of College Habits”), and a single copy of informed consent to the participants. Due to the privacy issues dealing with this project, to protect the participants’ identities in the study they will not be required to sign the informed consent form. There are a few initial questions dealing with basic demographic information, a question asking about GPA (both cumulative and previous semester GPA), several questions asking about the frequency of marijuana and alcohol use, and a few questions asking about other college habits (i.e. amount of study time per week, organizations that participant is in). The total number of questions is 16. The variable GPA will be taken from the questions listed above. Marijuana and alcohol use will both be determined by usage per month.

This study is a nonexperimental, correlation design. It will be conducted during the Spring semester of the 2004 academic year. Students will either sign up for the survey on a signup sheet posted on the psychology bulletin board or will be recruited by the researchers when they attend meetings of various student groups on campus or through various psychology classes with the consent of the professor teaching the class. Students will be given a single copy of the informed consent form and spaced far enough apart to ensure privacy while taking the 16 question, 10 minutes survey. Because of privacy issues, the participants will not be required to sign the informed consent sheet and will be told that by filling out the survey the participant will be giving implied consent (this information will be included on the informed consent sheet). Again, the survey is entitled “Survey of College Habits”. After completing the survey, the students will place the survey into an unmarked envelope and will be debriefed by the researchers. The questions from the survey will be coded and the data will be analyzed to see if a relationship between marijuana and alcohol use and academic performance exists.

The original hypothesis was that marijuana use and academic performance would have a positive relationship and the second hypothesis was that alcohol would have a negative relationship with academic performance. The number of participants in the study was 121. The mean cumulative grade point average was 3.26 (SD=.51). The mean previous semester grade point average was 3.25 (SD=.56). The mean for the age of the participants was 19.25 (SD=.96). In terms of class ranks, the participants were 57% freshmen, 27.3% sophomores, 7.4% juniors, and 8.3% seniors. Upon analysis of the data, the first hypothesis, that marijuana would have a positive relationship with academic performance, was not supported. A simple bivariate correlation between marijuana use and cumulative semester GPA was approaching significance (r=-.18, p=.06, ns) while the correlation between marijuana use and previous semester GPA was significant (r=-.31, p<.001). Futher manipulation of the data resulted in a multiple regression in steps that was performed with cumulative GPA as the DV. Alcohol was entered in the first step and it was found to be a significant predictor (b=-.198, DR2=.056, p<.05) but the addition of the marijuana use variable did not significantly explain additional variance (b=-.07, DR2=.004, ns.). Our second hypothesis, that alcohol use had a negative relationship with academic performance, was supported. Alcohol had a negative correlation with both cumulative GPA (r=-.24, p<.05) and previous semester GPA (r=-.22, p<.05). There were other findings of interest that were not directly related to the hypotheses. Alcohol consumption per month was positively related to the classes skipped per month (r=.33, p<.001) as was marijuana use (r=.39, p<.001). The percentage of drinking occasions that resulted in drunkenness had a positive correlation with classes skipped per month (r=.34, p<.001) and hours per week spent studying had a negative correlation with classes skipped per month (r=-.22, p<.05). Marijuana use had a positive correlation with alcohol use (r=.37, p<.001).

In the end, one hypothesis stood supported while another was rejected. Alcohol use was found to have a negative correlation with academic performance, as was hypothesized; marijuana use also had a negative correlation with academic performance, disproving the hypothesis proposed originally. Under further analysis of the data, it was found through a multiple regression that marijuana use actually did not account for additional variance in GPA once alcohol use was accounted for. Because of this, it can be inferred that the alcohol use of the particular student was the primary source of variance examined in this study within the student’s GPA and that marijuana use had little or no effect on this variance once alcohol use was accounted for. This particular study agreed with research from past studies. For instance, the study by Goode (1971), which found little difference between the grade point averages of marijuana users and nonusers, agrees with the findings in this study which suggest that marijuana has little effect on GPA once alcohol is accounted for. Brill (1982) also found that the great majority of students who experimented with marijuana found no adverse effects on their grades. These inferences conflict, however, with other studies, such as the one mentioned by Gergen, Gergen, and Morse (1972) which suggested that marijuana had a positive relationship with grade point average, and from which the original hypothesis was created. Picou, Wells, and Miranne (1980) found that alcohol use was negatively correlated with academic performance, similar to the results from our study. Our current study conflicted with Pico, Wells, and Miranne by finding a negative correlation originally between marijuana use and academic performance (while further inquiry revealed little correlation after alcohol use was accounted for) where Pico, Wells, and Miranne had found a positive relationship between marijuana use and academic performance. Unfortunately, this study was peppered with many limitations. The majority of the participants were freshmen college students. The freshmen lifestyle is indeed quite different from the experiences of the upper class years in the collegiate systems in many respects; this may have influenced the study by giving us an unrealistic picture that is skewed by the overrepresentation of freshmen in the study. Of course, the study was also limited by only including Loyola University students as participants. In the interest of time and efficiency many further questions related to the use of alcohol and marijuana were not placed on the survey, limiting the understanding of the effects different types of usage might have. This lack of depth may have given skewed results in that many factors were left unconsidered. Also, the survey itself was created by the experimenters and its validity has yet to be proven. This data could be useful for educators or students that want to understand the effects that their extracurricular pleasure activities might have on their academic performance. This study suggests that alcohol has a negative correlation with grade point average while marijuana has no correlation once alcohol is accounted for. This seems to imply that perhaps marijuana by itself has very little effect on the variance of grade point average once alcohol use is taken into the picture, an idea that seems contrary to popular belief and conventional attitudes. Further studies isolating marijuana usage from alcohol usage might reveal more on the subject. As mentioned in the results, marijuana use did have a positive correlation with alcohol use. The combined effects of both of the substances was not fully considered in this study, but further research in this area may reveal additional information. With more concentration on the effect the substances have independent of each other, further studies may also be able to explain this difference in correlations with more clarity. In particular, it would be interesting to study the academic performance of participants that smoke marijuana and do not drink, participants that drink alcohol and do not smoke marijuana, and students that abstain from both substances to examine the independent effects of the substances without the influence of the other. But at the same time, further research into the interaction between the two drugs could explain some of the difference in variance that was found in our study. As far as theoretical implications go, this study is limited because of the design of the experiment itself. With only correlations between variables to work with, no causal language can be used and the true effects of the substances can only be inferred or hypothesized. Given these limitations, a few ideas can still be constructed around the particular data that is available, although with little certainty as to the validity of the ideas. Without considering the multiple regression in steps, a simple bivariate correlation between marijuana use and academic performance was significant and was negative. What is of most interest is the multiple regression in steps performed that shows marijuana use added an insignificant amount of variance when alcohol use was already accounted for. Once again, because of the correlational design of this study, no true effects can be extracted from this information, but it does have some theorical implications that could prove interesting for further research. From this point, it appears that marijuana may not influence grade point average as powerfully as alcohol use. This suggests certain things about the nature of marijuana’s effect on the student. Perhaps marijuana by itself does little to impede the learning process, the ability to absorb and integrate information, and the ability to perform well on tests and assignments. Of course, the variables influencing a particular student’s grade point average are numerous, and nothing in this study explores the relationship between marijuana use and cognitive abilities or marijuana use and learning, but the possible implications of the data do seem to limit the negative effects marijuana use may have on grade point average. Further research in this area is a necessity if the relationship between these two drugs and their users is to explored further. A true experimental design is necessary to determine any kind of causality; considering the illegal status of marijuana, it would be unethical to run an experiment in which participants are asked to smoke or ingest marijuana. Hopefully the future will shed some light on this subject and increase the scientific and academic communities’ awareness of the effects of these substances in terms of academic performance.

Brill, N.Q. (1982). Psychological effects of marijuana use. American Journal of Social Psychiatry, 2, 41-44.Finnell, W.S., & Jones, J.D. (1975). Marijuana, alcohol, and academic performance. Journal of Drug Education, 5, 13-21.Gergen, M.K., Gergen, K.J., & Morse, S.J. (1972). Correlates of marijuana use among college students. Journal of Applied Social Psychology, 2, 1-16.Goode, E. (1971). Drug use and grades in college. Nature, 234, 225-227.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.Pullen, L.M. (1994). The relationship among alcohol abuse in college students and selected psychological/demographic variables. Journal of Alcohol and Drug Education, 40, 36-50.

Submitted 5/18/2004 11:55:13 AM
Last Edited 5/18/2004 11:58:24 AM
Converted to New Site 03/09/2009

Rated by 0 users. Users who logon can rate manuscripts and write reviews.

© 2017 National Undergraduate Research Clearinghouse. All rights reserved. The National Undergraduate Research Clearinghouse is not responsible for the content posted on this site. If you discover material that violates copyright law, please notify the administrator. This site receives money through the Google AdSense program when users are directed to useful commercial sites. We do not encourage or condone clicking on the displayed ads unless you have a legitimate interest in the advertisement.