The study of cannabis for treating depression is in its infancy, but the results are confusing. It seems using marijuana, especially strains high in the cannabinoid called cannabidiol (CBD), can help depression symptoms in the short term.
But in depressed people, long-term use of whole cannabis can exacerbate the problem, leading to more depressive episodes and more severe symptoms, according to the largest study on the matter to-date.
Researchers published their results in 2018 in The Journal of Affective Disorders. Some 12,000 entries from the pot-use self-reporting app Strainprint comprise the data.
Their conclusions? Your depression worsens insidiously: even as the drug continues to provide symptom relief for acute symptoms, it’s causing you to have more of these symptoms over time, leading to increased consumption, which worsens your depression even more.
The Strainprint study isn’t the greatest from a medical research standpoint, however. It’s entirely self-reported and there is no control group, so consider the conclusions with that caveat in mind.
In her 2017 paper, researcher Susan A. Stoner (I know, right?) of the University of Washington summed up the state of marijuana research and depression:
“Studies looking at whether marijuana use is associated with increased likelihood of development of depression have mixed findings: in some studies, associations have not been found when other variables associated with depression and marijuana use were taken into account,” Stoner writes.
Can CBD treat depression?
More promising for long-term treatment is the administration of CBD with little or none of the psychoactive chemical Delta-9 tetrahydrocannabinol (THC), long known to cause anxiety, which frequently occurs with depression.
Read our related article on “Weed Induced Anxiety“
Marijuana can have wildly different effects based on the strain, dosage and the person consuming it. A relatively mild strain, for instance, can kick off psychosis in the rare few predisposed to schizophrenia.
THC, the chemical mainly responsible for the marijuana high, has long been known to cause or worsen anxiety — especially when administered in isolation from the other cannabinoids and aromatic terpene chemicals in whole marijuana. THC is also the culprit in those rare cases in which marijuana use causes psychosis.
A synthetic THC called dronabinol (Marinol) had been on the market for cancer and AIDS patients for decades, and anxiety is one of the major listed side effects.
CBD, however, in recent years has become a darling of research chemists as they explore the ways it seems to tune the brain and gut in people suffering from neurological, psychiatric, digestive or mood problems.
A 2014 study showed anxiety and depression-reducing effects in purposefully stressed-out mice. CBD also has shown some effectiveness in protecting the brain from types of dementia like Alzheimer’s and for easing symptoms of chronic concussions, both of which conditions often cause depression.
Clinically, CBD is a powerful pharmaceutical. The FDA in 2018 approved a CBD-based drug to treat profound childhood seizure disorders, and it’s a component of medication used in Great Britain and Europe to treat symptoms of multiple sclerosis.
How does CBD work to treat depression?
Humans and other mammals have a neurological system of neurotransmitter chemicals and nerve receptors called the endocannabinoid system. THC especially and CBD to a lesser degree hijacks this system and replaces the neurotransmitter chemicals, leading to alterations in mood, sleep, perception, and other functions.
CBD, it seems, also activates other types of receptors on neurons — fitting into spots on the nerve cell wall like a molecular key to unlock a cascade of physiological effects. According to researchers, CBD appears to ease depression and anxiety by fitting into nerve receptors called 5-HT1A neuroreceptors.
This particular neuroreceptor is a target of established antidepressants. It’s involved in regulating the serotonin levels in the brain, the imbalance of which can cause all sorts of mental problems in addition to anxiety and depression.
What’s next in cannabis depression research?
As the medical and recreational legalization movement sweeps across North America, cannabis research for all sorts of ailments is filling up the research journals. Scientists have more access to the plant than ever before to tease apart the infinitely complex ways marijuana affects human health.
In June of 2018, McMasters University published plans for an 8-week pilot study to look at the effects of CBD on depression but had not started recruiting study subjects as of November 2018.
The U.S. National Institute on Drug Abuse is also planning a study to test whether CBD is addictive, using a control group and one using a benzodiazepine, a type of drug that is the current standard for prescribing patients with anxiety and depression.
Additional References For Depression Treatment with Marijuana:
“The relationship between cannabis use and measures of anxiety and depression in a sample of college campus cannabis users and non-users post state legalization in Colorado”
Lucy J. Troup et al