A recent study of people diagnosed with clinical depression has found that those using medical marijuana had lower depression scores than those who were not cannabis users. Researchers also determined that study participants who began using medicinal cannabis in a follow-up period saw a reduction in both depression and anxiety symptoms.
Depression affects more than 300 million people globally, according to statistics from the Hope for Depression Research Foundation, making it one of the most debilitating medical conditions in the world. In the United States, generalized anxiety disorder affects up to 4% of the population, or as many as 9 million people nationwide.
“Anxiety and depressive disorders are highly prevalent,” Erin L. Martin, lead author of the study and a Ph.D. candidate at the Medical University of South Carolina, told PsyPost. “Traditional antidepressants may effectively treat these disorders in a lot of people, but they do not work for everyone and can have unpleasant side effects.”
As an alternative to commonly prescribed pharmaceuticals, many people with anxiety and depression turn to cannabis products containing tetrahydrocannabinol (THC) or cannabidiol (CBD), or a combination of the two cannabinoids. However, scientific evidence of the efficacy of cannabis products to treat symptoms of anxiety and depression have not been conclusive.
“We conducted this study to determine if people that used medicinal cannabis products to treat symptoms of anxiety and depression reported improvement in these symptoms, as well as in other important areas like sleep and quality of life, relative to people that did not use medicinal cannabis,” Martin explained.
To conduct the study, which was published recently in the journal Frontiers in Psychiatry, researchers recruited a group of participants who reported having depression, anxiety, or both. Of them, 368 were medical cannabis users, while 170 said that they did not use cannabis medicinally but were considering doing so.
During a baseline assessment, participants answered questions about their cannabis use and completed assessments that gauge anxiety, depression, recent pain, quality of life, and sleep quality. Participants were invited to complete follow-up assessments every three months over a period of three years. Those enrolled in the study completed an average of two assessments during the course of research.
Among the study participants, 34% reported having anxiety, 15% reported having depression and 51% said they had both conditions. More than two-third (69%) also said they chronic pain disorder. CBD-dominant cannabis products were the most popular, with 82% of study participants reporting their use. Nearly a quarter (23%) reported using THC products, 7% said they used products with an equal balance of THC and CBD, and 5% used cannabis products with a minor cannabinoid.
Cannabis Users Had Lower Levels Of Depression
The participants who used cannabis at baseline, particularly CBD-rich products, reported lower levels of depression than nonusers. Those who used cannabis also reported higher quality of life, better sleep in the past month, less pain in the past month and were more likely to exhibit symptoms of depression that did not rise to the level of clinical concern.
Anxiety levels did not differ between cannabis users and nonusers at the onset of the study. Participants who were not cannabis users at the beginning of the research but began using cannabis medicinally during the follow-up period showed reductions in both depression and anxiety, as well as improvements in quality of life.
“Medicinal cannabis products, especially products high in CBD, may help to treat symptoms of depression, improve sleep, and increase quality of life,” said Martin. “There is also some evidence that medicinal cannabis may alleviate symptoms of anxiety, particularly if administered over an extended period of time, but this is less clear from our results and warrants further study.”
More Study Needed
Authors of the small study reported several limitations of the research, including a reliance on self-reporting and other factors, and recommended further investigation to explore efficacy and dosage.
“This is an observational study in a convenience sample, so it is possible that the results we observed could be partially attributable to a placebo effect or to people being more likely to complete the study if they found medicinal cannabis products effectively treated their symptoms,” Martin explained.
“Randomized, placebo-controlled trials on the antidepressant and anxiolytic effects of medicinal cannabis are needed,” she added. “Furthermore, it is still unknown how people should be dosing medicinal cannabis products in order to achieve the best effect (How much? How long? What cannabinoid content?) This should also be explored in future research.”