According to a new study published in the Yale Journal of Biology and Medicine, marijuana inhalation is associated with short-term reductions in depressive feelings. The study was epublished by the National Institute of Health, and is titled The effectiveness of cannabis flower for immediate relief from symptoms of depression.

For the study researchers examined the effects of marijuana inhalation on depressive feelings in 1,819 subjects over a one-month period. Study participants self-administered marijuana and reported symptom changes in real time on a mobile software application.

According to researchers “almost all patients in our sample [96 percent] experienced symptom relief from using cannabis to treat depression.. with an average symptom intensity reduction of –3.76 points on a zero-to-ten visual analogue scale.”

Marijuana varieties that were dominant in THC were used. Researchers reported “minimal evidence of serious side-effects in the short run,” though they acknowledged that prior studies have shown “mixed findings on the association between cannabis use and symptoms of depression, with unclear conclusions as to the direction of causality.”

They concluded: “Our results indicate that THC in particular is positively correlated with an immediate reduction in the intensity of depressive feelings. … Future research on cannabis and depression is needed, directly comparing the short- and long-term treatment effectiveness and side effect severity of cannabis use with conventional antidepressant treatment, in conjunction with conventional treatment approaches, and in the presence of clinically discouraged behaviors, such as alcohol consumption.”

The full abstract can be found below:

Objective: Scientific research on how consumption of whole, natural Cannabis flower affects low mood and behavioral motivations more generally is largely nonexistent, and few studies to date have measured how common and commercially available Cannabis flower used in vivo may affect the experience of “depression” in real-time. Methods: We observed 1,819 people who completed 5,876 cannabis self-administration sessions using the ReleafApp™ between 06/07/2016 and 07/08/2019, with the goal of measuring real-time effects of consuming Cannabis flower for treating symptoms of depression. Results: On average, 95.8% of users experienced symptom relief following consumption with an average symptom intensity reduction of –3.76 points on a 0-10 visual analogue scale (SD = 2.64, d = 1.71, p <.001). Symptom relief did not differ by labeled plant phenotypes (“C. indica,” “C. sativa,” or “hybrid”) or combustion method. Across cannabinoid levels, tetrahydrocannabinol (THC) levels were the strongest independent predictors of symptom relief, while cannabidiol (CBD) levels, instead, were generally unrelated to real-time changes in symptom intensity levels. Cannabis use was associated with some negative side effects that correspond to increased depression (e.g. feeling unmotivated) in up to 20% of users, as well as positive side effects that correspond to decreased depression (e.g. feeling happy, optimistic, peaceful, or relaxed) in up to 64% of users. Conclusions: The findings suggest that, at least in the short term, the vast majority of patients that use cannabis experience antidepressant effects, although the magnitude of the effect and extent of side effect experiences vary with chemotypic properties of the plant.