Many have researched the effects of marijuana on people with anxiety and other psychological disorders. However, much of the research has been inconclusive. That is to say, many of the researchers have found no correlation between marijuana use and a decrease or increase of anxiety and depression symptoms. Some research does suggest that there is a correlation, whether it is a positive one or a negative one has still to be determined.
Much of the research done to find the effects of marijuana on people with anxiety has been flawed in one type of way or another. Some did not use proper research techniques, causing the research to produce incorrect results while others did not sample properly, also causing incorrect and conflicting results. The studies I found seem to be legitimate in their sampling and the way they collected the data. The study conducted by Victoria Grunberg, Kismet Cordova, Cinnamon Bidwell, and Tiffany Ito was very thorough in their selection of participants. The students that were interested in participating in the study were first interviewed over the phone to determine if their marijuana use fit into the study. They were looking for students that never used marijuana, students that were relatively infrequent users, and regular, frequent users. Both the frequency and quantity criteria were in place to make sure that the marijuana usage reflected stably in their research. In addition to that, any individual that reported histories of head trauma, neurological disorders, and the use of prescription drugs, with the exception of birth control and medical marijuana, were excluded from the study.
They oversampled people with low marijuana usage levels because they thought those people would be more likely to change their usage over the three-year study period. Participants self-reported their marijuana use for the past thirty days before the study using the Time-Line Follow Back created by Linda Sobell and Mark Sobell in 1992 which used a calendar-assisted structured interview where the participants indicated the quantity of marijuana used on each day. With other substances like nicotine or alcohol, people may drink an entire beer or smoke an entire cigarette, but with marijuana they may only take a few hits. Since there are many different ways to consume marijuana the main analyses they used was marijuana use frequency as their measure of marijuana use. They also conducted secondary analyses with marijuana quantity measures but yielded the same results (Grunberg, Cordova, Bidwell, and Ito, 2015). The researchers used the Achenbach System of Empirically Based Assessment Adult Self-Report (ASR) created by Achenbach and Rescorla in 2003 to measure the participants symptoms of anxiety and depression (Grunberg, Cordova, Bidwell, and Ito, 2015).
Since the study was focused on the effects of marijuana on symptoms of anxiety and depression the researchers were highly interested in any anxiety and depressive problems shown in the participants. They were asked how well each item described them over the past six months ranging from zero to two. Anxiety items were assessed with seven items and depressive problems were assessed with fourteen items (Grunberg, Cordova, Bidwell, and Ito, 2015). A total score was created for each construct with higher scores reflecting a incessant measure of greater confirmation of anxiety and depressive problems. The participants that met the criteria were asked to take part in a total of six laboratory sessions over three years. The data presented in the study came from the first sessions in year one and two where marijuana usage, temperament, and psychopathology were assessed. The assessments were given approximately twelve months apart (Grunberg, Cordova, Bidwell, and Ito, 2015).
Participants were asked to not use alcohol for twenty-four hours, recreational drugs, including marijuana, for six hours, and caffeine and cigarettes for one hour before each laboratory session. In both session participants were breathalyzed to ensure a breath alcohol concentration of zero. A verbal verification was used to make sure participants adhered to the other abstinence requirements. The only reason they did not do the preferred biochemical check was because it was too expensive and were prohibited from conducting it.
Although failure to meet the requirements could add variability to the responses none of the participants were visibly impaired and the researchers had no reason to think that failure to comply to the abstinence requirements would cause any problems in the outcome of the study. The results of the study indicated that a higher frequency of marijuana use actually decreased the anxiety over time. However, depressive symptoms increased with high frequency marijuana use. The study conducted by Natasha Wright, Danny Scerpella, and Krista Lisdahl was also very thorough. They recruited eighty-four participants through newspaper advertisements and fliers. Forty-two participants were marijuana users while the other forty-two were not. They had to be fluent English speakers between the ages of eighteen and twenty-five. The marijuana users had to have smoked more than ten times in the past year or more than five hundred times in their lifetime and less than ten other drug uses, like ecstasy or cocaine. The healthy controls had to have smoked less than five times in the last year and less than twenty times in their lifetime. If the person was left-handed they could not participate.
They also could not participate if they had prenatal issues, such as being born before thirty0five weeks, or if their mother had drunk more than seven drinks a week while pregnant with them. They were also excluded for any major medical or neurologic disorders. The participants that did make it were asked to abstain from alcohol and drug use for seven days leading up to the study session. They confirmed this with a self-report along with a toxicology screen (Wright, Scerpella, and Lisdahl, 2016). This study showed that female marijuana users have significantly higher anxiety rates than the female controls, the females that did not smoke marijuana. Their anxiety rates were also higher than male marijuana users and male nonusers. The female marijuana users also had higher disinhibition rates than nonuser females and all the males. The goal of this study was to assess whether or not marijuana users demonstrated higher symptoms of anxiety, depression and behavioral symptoms of executive dysfunction, while controlling for the effects of alcohol, cotinine, and ecstasy. They also wanted to examine any potential gender differences in those effects. Their findings suggest that after one week of not smoking the marijuana users showed significantly greater depressive symptoms with a decrease in fun seeking, reward response, and Behavioral Approach Scale total scores. The gender of the participants pointedly interacted with marijuana use with females showing higher levels of disinhibition and anxiety. Their results showed to be consistent with other findings that say marijuana use leads to increased levels of anxiety and depressive symptoms (Wright, Scerpella, and Lisdahl, 2016).
With all of this being said, part of the reason the results are largely inconsistent is because of the ratio of tetrahydrocannabinol (THC) and cannabidiol (CBD) in the marijuana used by each of the participants. THC is the main psychoactive component in cannabis. At particular doses and under specific conditions THC has been shown to have antidepressant, hypnotic, and anxiety reducing effects in patients suffering from cancer, multiple sclerosis, and even in some healthy patients. However, higher doses of THC have demonstrated the opposite effect which includes inducing panic, paranoia, and anxiety in certain subjects. Chronic exposure to THC has also shown to be neurotoxic. Which has been a point of concern since the THC to CBD ratio in street cannabis has increased over the decades (Turna, Patterson, and Ameringen, 2017).
- Grunberg, V. A., Cordova, K. A., Bidwell, L. C., & Ito, T. A. (2015). Can marijuana make it better? Prospective effects of marijuana and temperament on risk for anxiety and depression. Psychology of Addictive Behaviors, 29(3), 590-602. doi:10.1037/adb0000109
- Turna, J., Patterson, B., & Ameringen, M. V. (2017). Is cannabis treatment for anxiety, mood, and related disorders ready for prime time? Depression and Anxiety, 34(11), 1006-1017. doi:10.1002/da.22664
- Wright, N. E., Scerpella, D., & Lisdahl, K. M. (2016). Marijuana Use Is Associated with Behavioral Approach and Depressive Symptoms in Adolescents and Emerging Adults. Plos One, 11(11). doi:10.1371/journal.pone.0166005