Researchers from Columbia University and the City University of New York (CUNY) conducted this study “to estimate trends in the prevalence of cannabis use and risk perceptions of cannabis use from 2005‐2017 among United States persons with and without depression.”
Data for the study was collected from the National Survey on Drug Use and Health, an annual survey that asks Americans to self-report their drug use, mental health, and other health-related issues.
The study authors looked at data from 728,691 people ages 12 and older who took the survey between 2005 and 2017. From this data set, researchers looked at the number of respondents who reported suffering from depression within the past year, as well as the number who reported using cannabis within the past month. The authors also examined whether or not respondents thought that there was a “great risk associated with regular cannabis use.”
Overall, the prevalence of cannabis use increased slightly from 2005 to 2017 for all Americans who answered the study. But for those suffering from depression, researchers found that using cannabis was much more common. In 2017, 18.9 percent of respondents with depression reported using weed within the past month, compared to 8.7 percent of those without depression. Daily pot use was reported by 6.7 percent of those with depression, compared to 2.9 percent of those without.
Individuals with depression were also less likely to think that using pot regularly posed any significant risks to them. When looking at specific demographics, the researchers also found even stronger connections between cannabis use and depression. Using pot was more common among younger adults suffering from depression, with 29.7 percent of depressed 18-25 year olds reporting recent use in the past 30-days.
“Perception of great risk associated with regular cannabis use was significantly lower among those with depression in 2017, compared with those without depression, and from 2005 to 2017 the perception of risk declined more rapidly among those with depression,” said corresponding author Renee Goodwin, PhD, MPH, of Columbia University and CUNY. “At the same time, the rate of increase in cannabis use has increased more rapidly among those with depression.”
Previous studies have discovered correlations between cannabis and depression or other forms of mental illness. These studies are often misinterpreted as proof that weed can cause depression, but no research has conclusively found this to be true. The present study suggests that the correlation between cannabis and depression is explained by the fact that depressed individuals are more likely to use weed to feel better than those who are not depressed.
Anecdotally, many cannabis users have reported that weed helps them deal with symptoms of depression, but there are relatively few robust research studies on the topic. One recent study has found that cannabis can help reduce suicidal thoughts among people suffering from PTSD, but so far, no US state has accepted depression as a qualifying condition for medical marijuana.