Researchers from Yale University have found that cannabis has short-term antidepressant effects in the vast majority of people.
For the study, the researchers observed 1,819 people who logged real-time effects of 5,876 cannabis experiences using the ReleafApp, an app that helps people track their historical experiences with the substance.
Their goal was to see whether using the substance helped relieve depression in patients already using cannabis to treat the condition.
The patients logged in data indicating what kind of cannabis they used, how it was administered, what symptoms occurred, and how they changed over time. The central parameter investigated was ‘symptom relief’, recognized as the difference between symptom intensity at the beginning and end of each cannabis session. All data were collected between July 2016 and August 2019.
All in all, the researchers found that 95.8% of users reported symptom relief from depression. Meanwhile, 2.1% reported a worsening of depressive symptoms, and 2.1% reported no change at all. More than this, users suffering from depression tended to notice a 3.76 point decrease on a 10-point scale in depression (from 5.85 to 2.08).
The researchers also noted that cannabis strain (Indica, Sativa or hybrid) had no impact on the reduction in depressive symptoms. They did note, however, that higher tetrahydrocannabinol (THC) levels tended to lead to more symptom relief, whereas cannabidiol (CBD) was generally unrelated to changes in symptom intensity.
Although interesting findings, the researchers note that as the study did not include a control placebo group, no conclusions should be made just yet. They also note that the study focused on the short-term effects of cannabis as opposed to long-term effects. Furthermore, as those in the study already used cannabis, it may not be possible to generalize these results to other demographics do not use it already.