Compounds in marijuana have been found to act like antidepressants.
Depression is one of the most common mood disorders. The low mood and sadness caused by depression can make daily life feel nearly impossible.
Many people believed for a long time that marijuana could help symptoms of depression. Recently, scientists have started to study exactly how marijuana can ease depression symptoms.
Here, we discuss the scientific support for using marijuana to treat depression.
What is Depression?
Depression is a disorder that results in a very low mood, making daily activities like working, eating and sleeping much more difficult than normal. Depression can strongly influence thoughts and feelings.
Symptoms of depression include feeling sad, low energy, lack of motivation, difficulty concentrating, and irritability.
People with depression often lose interest in activities they once enjoyed, and begin to believe negative things about themselves. It is also common for people with depression to suffer from anxiety disorders or to experience chronic pain.
Even though depression is one of the most common mental health disorders, it it still a serious condition. People with depression have an increased risk of suicide.
Depression is typically treated with a combination of prescription medications (antidepressants) and psychotherapy such as CBT.
Can Marijuana Help With Depression?
The use of marijuana to treat depression dates back to ancient times. Today, marijuana is not commonly prescribed for depression, but many people still use it for its antidepressant effects.
“A lot of people report using cannabis effectively to treat depression,” says Dr. Zachary Walsh, an assistant professor of psychology at the University of British Columbia who heads a research lab focused on marijuana and mental health.
Despite a lack of human studies, there is some evidence that marijuana can help treat depression.
Marijuana may also help to treat depression by increasing serotonin in the brain. Serotonin is a naturally-occurring brain chemical that controls mood, sleep and appetite. It’s the brain chemical that most antidepressant medications target.
A 2007 study found that by activating serotonin, cannabis can act as an antidepressant in animals.
The body makes compounds known as endocannabinoids that work in a similar way to marijuana. A 2015 study found that increasing anandamide, one of these natural cannabinoids, can result in antidepressant effects.
THC vs. CBD For Depression
Effects of THC
The study of THC and depression is limited, but research so far has suggested that THC can help to treat depression.
A 2010 study found that THC can act as an antidepressant in animals. The researchers found that there was an optimal dose, and that THC above or below the optimal dose could make depression worse.
Because this optimal dose is likely different for everyone, people who self-medicate their depression should be aware that they will probably need to test a couple doses of THC in order to find what works best for them.
A 2012 study found that long-term treatment with THC increased BDNF — a brain protein that is lower than normal in people with depression. This increase in BDNF by THC resulted in antidepressant effects.
Effects of CBD
There is more research into the antidepressant effects of the non-psychoactive cannabinoid CBD. Overall, studies suggest CBD can likely help depression.
A 2014 study reviewed all the animal studies of CBD and depression, and concluded that CBD can act as an effective antidepressant.
A 2016 study also found that CBD can act as an antidepressant, likely by activating both the endocannabinoid and serotonin systems.
There have also been some studies into which symptoms of depression CBD is able to relieve. A 2016 study found that CBD can treat anhedonia, the symptom of depression that causes people to lose the ability to feel pleasure.
CBD may also be a good treatment option for people that need fast results. A 2016 study found that CBD can act as a fast-acting antidepressant.
Cannabis vs. Antidepressants
While researchers can’t completely confirm if marijuana is effective for treating depression, Dr. Walsh points out that other medicines fall into the same problem.
He says that in some cases, typical antidepressants are no more effective than a placebo and have side effects that may be more severe than those of marijuana.
There is some research that suggests marijuana and antidepressants may even work well together.
A 2011 study found that because the endocannabinoid and serotonin systems interact in the body, marijuana may even help some antidepressants to work better.
However, in order to declare a drug effective for a certain disease, it must go through different stages of clinical trials, which marijuana has not.
“If we want to take a rational approach about medicinal cannabis, we should go through systematic clinical studies and finally determine its efficacy in treating specific diseases and its safety compared to standard antidepressants,” says Dr. Gabriella Gobbi, an associate professor in the Neurobiological Psychiatry Unit at McGill University.
Dr. Walsh agrees that further research should compare cannabis to commonly used antidepressants. “Then I think people can make the choice,” he concludes.
Can Marijuana Cause Depression?
Some people may have a higher risk of developing depression with heavy cannabis use. However, research is not entirely clear due to problems with correlation and causation.
A 2014 paper reviewed 57 studies on the effect of cannabis on depression. Many studies found that heavy cannabis use can increase the risk of depression, but the results were highly mixed.
On the other hand, there may be certain people who are more likely to develop depression from smoking marijuana.
A 2016 study found that high levels of marijuana use can lead to worse suicidal thoughts in people that have a history of depression.
Correlation vs. causation
Some studies have found a link between marijuana use and depression, but it is hard to know from the results whether marijuana plays a causal role.
“What those studies have noted is that they can’t really determine what comes first,” Dr. Walsh explains.
In other words: “Does cannabis cause depression? [Or] do depressed people try to use cannabis to help with depression? Those are questions that are out there,” says Dr. Walsh.
Young people may be at risk
Teens and young adults also seem to be more likely to experience depression, especially if they consume large amounts of marijuana.
According to research conducted by Dr. Gabriella Gobbi at McGill University in 2010, daily use of marijuana seems to cause depression and anxiety in teens.
A 2015 study also found that university-aged young adults are more likely to have a higher risk of developing depression from heavy marijuana use.
Another study of university students in 2016 found that regular, casual use of marijuana was linked with symptoms of depression.
Depression is the most common mood disorder, and it can seriously impair peoples’ ability to function and carry out everyday tasks.
Recent studies suggest that marijuana can be an effective treatment for depression, and that it may even work to enhance the effectiveness of antidepressant medication.
Both THC and CBD have been found to act as antidepressants, but there is stronger evidence that supports the use of CBD as an antidepressant.
However, teens, young adults, and people at high risk of developing depression should be cautious with marijuana. There is evidence that marijuana may actually make depression for these people worse.
Future studies are needed to confirm the best way to use marijuana to help treat depression.