Cannabis use is often associated with having health benefits, from relieving anxiety to easing pain. There is currently a large interest in finding alternative treatments for mental illnesses such as post-traumatic stress disorder and depression. The difficulty in evaluating what cannabis can or can’t do resides in finding compelling clinical evidence of claims regarding cannabis’s medical properties.
Some researchers, however, still wonder whether cannabis use —- particularly, daily cannabis use —- might inflict certain health conditions. Past studies have argued that prolonged cannabis use among adolescents can lead to short-term memory loss and other cognitive effects lasting several weeks or months due to brains that haven’t completely formed. 
A 2020 investigation considered cannabis’ correlation with depression.  Researchers evaluated how prevalent depression was among past-month daily or near-daily cannabis users. Each participant (of 16,216 men and women) was given the Patient Health Questionnaire-9 (PHQ-9) — which indicates whether depression is present or absent —- followed up by a physical exam. 
The study reported that cannabis use (past-month users) increased from 12.24% in 2005 – 2006 to 17.30% in 2015 – 2016. With this increase in past-month use, the survey also found daily use increased from 3.78% to 6.06% during the same respective time.  This increase makes sense because public perception has gradually changed in favor of cannabis. Thanks to legalization, more people have access to it. And thanks to more research, positive information about the plant is spreading like wildfire.
The study also found that “individuals with depression had approximately double the odds of using cannabis compared to people without depression; and the association between depression and cannabis use strengthened from 2005 to 2016.”  It was found that by 2016, those struggling with depression were at 216% higher odds of using cannabis near-daily. 
While this study demonstrates a correlation between depression and cannabis use, we really need more research to properly understand how this correlation works. Sufferers of depression report using cannabis to find relief.  So, with increased legalization running parallel to increased cases of depression in modern times (and that link was pre-2020), it makes sense that sufferers of depression turn to cannabis with greater frequency.
Unfortunately, however, these researchers conclude that “the findings of this study indicate that individuals with depression are at increasing risk of cannabis use, with a particularly strong increase in daily or near-daily cannabis use.” And when you take prescription medication, you typically take that medication daily, right? So, why would it be any different with medical cannabis?
The researchers wrote that “these results could also be interpreted as indicating that an increasing proportion of individuals who use cannabis are developing depression.” (Can see the mainstream news outlets having a field day with that line.) They caveated that remark, however, by highlighting that if that was the case, as cannabis use increased, so should the prevalence of depression. Their findings showed that “depression stayed relatively stable during the study period, not supporting the latter interpretation.”
Once research has reached a point where we can better understand how cannabis use affects depression, those struggling will have a better opportunity to find treatment.
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- Jacobus J, Tapert S. Effects of cannabis on the adolescent brain. Current Pharmaceutical Design. 2015;20(13). [Journal Impact Factor: 2.208; Times Cited: 112]
- Gorfinkel LR, et al. Association of depression with past-month cannabis use among US adults aged 20 to 59 years, 2005 to 2006. Jama Network. 2020;3(8). [Journal Impact Factor: 5.032; Times Cited: n/a]
- Sexton M, Cuttler C, Finnell JS, Mischley LK. A Cross-Sectional Survey of Medical Cannabis Users: Patterns of Use and Perceived Efficacy. Cannabis Cannabinoid Res. 2016;1(1):131-138. [Journal Impact Factor: n/a; Times Cited: 45]