Frequency of cannabis use and symptoms of anxiety and depression: a cross-sectional analysis of the Colorado cannabis users health cohort

Cannabis is commonly used as a self-prescribed treatment for anxiety and depression, but few studies have evaluated these associations using both validated mental health scales and biological cannabinoid markers. This study aimed to test associations between cannabis use frequency and symptoms of anxiety and depression, and to examine whether frequent cannabis users with high symptom scores were less likely to use FDA-approved medications. This is a secondary analysis of a cross-sectional study on sleep and cannabis use, including 195 participants who completed the Hospital Anxiety and Depression Scale (HADS), Beck Anxiety Inventory (BAI), Beck Depression Inventory-II (BDI-II), and self-reported cannabis use. Urinary tetrahydrocannabinol (THC) metabolites validated recent cannabis exposure. Regression models adjusted for demographic and clinical variables. Frequent cannabis use (≥ 15 uses in the past 30 days) vs. infrequent use (14 or fewer uses in the past 30 days) was associated with higher likelihood of anxiety, AOR = 1.06 (95% CI 1.01, 1.12), p < 0.01 for the BAI and AOR = 1.05 (95% CI 1.01, 1.09), p < 0.05 for the HADS-A. However, frequency of cannabis use was not associated with depression for either the HADS-D, AOR = 0.98 (95% CI 0.94, 1.05) or BDI-II, AOR = 0.98 (95% CI 0.92, 1.04), ps > 0.05. Use of FDA-approved anxiolytic or antidepressant medications did not significantly differ by non-use, infrequent, and frequent cannabis use groups (20% vs. 18.2% vs. 21.1% for anxiolytic-hypnotics and 14% vs. 9.1% vs. 11.4% for antidepressants), and urinary cannabinoid levels were not associated with symptom severity, all ps > 0.05. Elevated anxiety was common among frequent cannabis users, yet use of FDA-approved medications was infrequent in this group despite increased symptom burden. These results suggest that some individuals may turn to cannabis to manage their symptoms instead of using evidence-based treatments. Clinicians should consider the possibility that patients might substitute cannabis for prescription medications, and routinely screen cannabis users for untreated anxiety. Randomized studies are needed to determine causal associations between anxiety symptoms and cannabis use, including potential interactions with FDA-approved pharmacotherapies. Such evidence will inform clinical recommendations and policy on cannabis use and mental health.