Association of cannabis use with depression among cancer patients.

The rate of cannabis use by cancer patients is climbing. However, as the risk of mental illness caused by cannabis use in cancer patients has not been effectively evaluated, this study will analyze the association between cannabis use and depression in cancer patients. This study collected data from respondents to the National Health and Nutrition Examination Survey from 2005 to 2018. A total of 22,181 respondents self-reported information about cannabis use in questionnaire, of which 893 were diagnosed with cancer. We found that the rate of cannabis use among cancer patients increased each year from 2005 to 2018. We analyzed the association between cannabis use and depression in cancer patients by multivariable logistic regression. Results found that the current cannabis use had a significant positive correlation with increased risk of depression in cancer patients (OR = 2.135, 95% CI = 1.21-3.777, p = 0.009). In our stratified analysis, current cannabis use was associated with an increased risk of depression in cancer patients who were female, had a history of cocaine use, and initiated cannabis use after age 17. (OR = 1.981, 95% CI = 1.024-3.85, P = 0.043; OR = 3.19, 95% CI = 1.61-6.41, P < 0.001; OR = 2.236, 95% CI = 1.018-4.967, P = 0.045). In conclusion, the use of cannabis by cancer patients has an associated risk of depression and the cancer patients who currently use cannabis are more likely to have depression.