There are many kinds of depression, which refers to a condition of sadness or despair. Some forms are normal transient states of low mood caused by life events or in response to daily stressors. It can be triggered by changes in sleep, light, food, medications or changes in health. The result is a change in brain chemistry. About 50% of people with depression have a co-existing medical problem that also needs to be treated. Depression often leads to changes in sleep patterns, eating habits, fatigue, poor concentration, social withdrawal or irritability.
Depression and Cannabis
NOTE FOR FIRST TIME READERS: Cannabinoids – such as THC, CBD – and terpenes are the main medically active components in cannabis (aka marijuana). For more information on these components, and much more about the plant, see our section on the Science of Cannabis.
Cannabinoids have been found to have antidepressant properties depending on the type of cannabis used and its dosage. Some recent studies have linked depression to chronic use of cannabis (several times a day for several years), but there are other studies that say different. A 2005 Australian report reviewed thousands of heavy cannabis users and found normal rates of depression when it accounted for other factors such as alcohol use, gender, illness, etc.. A study in the Journal of Neuroscience published in 2007 showed that cannabinoids elicit antidepressant effects and activate serotonergic neurons at low dose levels. It is becoming apparent that the correct dosage is important in mood control.
Cannabis use has also been used as a method of harm reduction (reducing the negative impacts of other drugs), to substitute for a more detrimental substance use. Rates of depression in substance abusers are three times higher than in the normal population. Often substance abusers are self-medicating because of depression and studies show that drug abuse itself leads to brain changes and depression, which only make a bad situation worse.
Understanding cannabis effect on depression depends on several variables. The response of an individual patient can depend on the levels of THC and cannabidiol (CBD) or what is called the potency and cannabinoid profile of the plant. It’s now thought that the terpene profile, that determines many strain characteristics of the plant, is also most important in mood effects. Strain selection is important because some are more sedating and may contribute to the lethargy of depression. In general sativa dominant strains are more uplifting.
Denson TF, Earleywine M, Decreased depression in marijuana users. Addict Behav. 2006, 31(4): 738-42.
Bambico FR, et. al., Cannabinoids elicit antidepressant-like behavior and activate serotonergic neurons through the medial prefrontal cortex. The Journal of Neuroscience. 2007, 27(43): 11700-11711.
Swift W, et al. Survey of Australians using cannabis for medical purposes. Harm Reduction Journal. 2005, 4: 2-18.