Link Between Marijuana And Memory

Marijuana is one of the most commonly used recreational drugs amongst young adults in the United States. The main component in marijuana is called tetrahydrocannabinol, also known as THC (Guess What’s in Your Marijuana, 2016). Marijuana goes by a variety of names such as: pot, grass, maryjane, chronic, and ganja to name a few. Individuals use marijuana medically and recreationally. If individuals are living in an area where it has been legalized recreationally, one must be twenty-one years of age in order to consume and purchase marijuana (Map of Marijuana Legality by State, 2019). Over the last decade or so, marijuana has been both decriminalized and legalized in many of the states within the United States. Depending on the place of residence of the individual will determine the laws and stipulations that are set in place if one was to be in possession of marijuana (Map of Marijuana Legality by State, 2019).

In Rhode Island specifically, this topic has been on the rise since the neighboring state of Massachusetts has recently legalized marijuana for recreational purposes and opened up its first dispensaries (Map of Marijuana Legality by State, 2019). One of the dispensaries is as close as Seekonk which is right over the Rhode Island line which means that those who are living in Rhode Island are constantly crossing over in order to purchase since all one needs is proper identification proving that they are of age.

Marijuana affects each person differently; studies have been conducted to see if marijuana causes any deficits in various age groups. For examples, researchers recruited adolescents who were from North Carolina (Dougherty, et. al., 2013). The participants in the study were separated by those who used marijuana and those who were non-users. The non-users did not have any history with marijuana and the users in the study recorded that they have used marijuana at least four times a week. During the experiment, they wanted to compare the usage of marijuana and the performance on multiple cognitive task that included measuring attention, memory, decision-making and impulsivity (Dougherty, et. al., 2013). Researchers in other areas such as New York took a different approach when it came to measuring the effects on marijuana. Cheryl Corocran (2014) conducted an experiment that measured spatial memory, except she ran this experiment by using monkeys. Corocran (2014) had given the monkeys marijuana for six months in their adolescent ages. Like the study conducted by Dougherty, et. al., (2013) the researcher had also been looking at those who have been exposed to marijuana five times a week for the past six months. Corocran (2014) demonstrated a task that had the monkeys look at a screen for different time intervals that were either 1,4,8, or 16 seconds. During this task there were random squares that had been placed in the corners and the monkeys had to remember where the square had been beforehand. The squares in this experiment were randomly colored. When choosing were the squares were, researchers found that the reaction time and the accuracy of the colored square were not affected by the exposure of marijuana. Unlike the study that was conducted by Dougherty, et. al., (2013) researchers in that study found that there were deficits in the cognitive testing that they ran. Short-term memory was affected and showed an association with marijuana. With this study, they used adults and adolescents. Within this study it was found that the adolescents demonstrated a greater decrease in recall memory than the adults did.

Another study that was conducted by Leonie Welberg (2014) discusses how marijuana usually has some negative side affects when consuming it that usually contain cognitive impairments, but a new study suggested that the usage of marijuana actually increases levels in an individual’s hippocampus (Welberg, 2014). To obtain these results, researchers injected mice with tetrahydrocannabinol. Mice received daily injections of THC for four weeks. The injections of the THC caused changes in the hippocampus. The hippocampus which is an important part of the brain that is responsible for short term and long-term memory expressed several changes in cyclooxygenase 2, better known as COX2 levels (Welberg, 2014). COX2 levels are shown to decrease the negative affects and impairments. With the COX2 levels decreasing, these levels are show to demonstrate how the negative side affects of marijuana are being eliminated. Takagi, et. al., (2011) wanted to examine verbal memory, learning and executive functions. Researchers wanted to compare the usage of inhalant use to those who use marijuana. To retrieve these results, Takagi, et. al., (2011) recruited both adolescents and adults. The participants in this study were put into three different groups. The groups consisted of marijuana users, inhalant users and a control group of non-users. The participants performed a word recall task that ran for 15 trials. The participants in this study were also told to reframe from using any drug for at least 24 hours. The findings of this experiment demonstrated that the non-users performed better than the inhalant and marijuana users, but the marijuana users performed better than those who have done inhalants.

There are many stereotypes that come along with being a user of marijuana. Some of them include: “marijuana kills all of your brain cells”, “marijuana is a gateway drug”, “stoners are lazy and unmotivated”. These stereotypes have been ongoing for a really long time. It is essential that individuals recognize all the benefits and the downfalls of marijuana because of how widespread it is discussed. I will hypothesize that the results from conducting this experiment will result in individuals not being negatively affected by being under the influence of marijuana. Results from this experiment will show that marijuana will not cause any deficits in memory and that their response time will be the same as those who are not under the influence of marijuana.

Proposed Methods

Participants. There will be 100 participants in this experiment. Participants will be individuals who are at least 18 years of age and are college students. Participants will be recruited by a flyer that is posted on their college campus.

Design. This is a 2×2 factorial design. The independent variable in this experiment will be marijuana use. There will be two different conditions within the experiment, users and non-users of marijuana. The dependent variables will be memory and response time.

Materials

 Brownies will be provided to the participants in the experiment. The use of a Wisconsin Card Sorting test will be assigned to each of the participants. The Wisconsin Card sorting task is a task that has been used in psychology for many of years to measure cognitive functioning. Participants will each be given a computer to complete the given task.

Procedure

Students will go to a research lab where the study will be conducted and sit at a desk top computer. Once all the participants are in the lab, those who have identified themselves as a marijuana user will ingest a brownie that contains tetrahydrocannabinol. There will be a 15-minute waiting period for all participants. This will allow for all participating to be able to settle in and to access the task that they will be completing. After 15 minutes, all the participants will begin the task. During the task, participants will be asked to electronically sort 128 cards that have different figures, colors, and number of objects on them. The figures on the cards will have crosses, circles, tringles and stars on them. The colors on the cards will be either red, blue, yellow or green and the number of objects on the cards will be either one, two, three or four. When the test begins there are four cards that are shown on the screen before the participant. The cards that are shown at the beginning are one red triangle, two green stars, three yellow crosses, and four blue stars. Participants are told to sort each of cards under the given stimulus cards to which they think is correct. This will be repeated until all of the 128 cards are gone (Singh, Aich, & Bhattarai, 2007). Once the test has been completed there will be a task summary at the end that records how long it took each participant to answer the question and their percentage correct. Once the participants have reached this part of the experiment, they will be allowed to leave the lab.

Results

To analyze these results, an ANOVA will be conducted. The predicted results will conclude that the usage of marijuana does not cause any deficits in memory and will not cause an individual to take any longer to respond to a given question compared to those who are not under the influence of marijuana. These results could conclude that marijuana makes individuals to be able to concentrate and focus more.