Cannabis Legalization Drove Greater CUD Increases Among Veterans with Psychiatric Disorders

CUD prevalence among veterans with any psychiatric disorder rose from ~3.3% in 2005 to ~5.7-6.4% by 2022, depending on state legalization status. Using staggered difference-in-difference analysis, both medical and recreational cannabis legalization were associated with significantly greater CUD increases among patients with psychiatric disorders (depression, PTSD, anxiety, bipolar, psychotic-spectrum) compared to those without. CUD prevalence remained below 1% in all years among patients without psychiatric disorders.

Analysis of VHA electronic medical records (2005-2022) for patients aged 18-75 with primary care, ED, or mental health visits. Sample sizes ranged from 3.2 to 4.4 million per year. Staggered difference-in-difference models estimated effects of medical and recreational cannabis legalization on CUD prevalence, comparing patients with and without specific psychiatric disorders.

This is one of the largest and longest studies connecting cannabis legalization to CUD outcomes in a vulnerable population. The finding that psychiatric patients are disproportionately affected by legalization has direct implications for how states approach cannabis policy alongside mental health care.

Cannabis legalization is primarily discussed as a social justice and economic issue, but this study quantifies a specific health cost: more cannabis use disorders among the most psychiatrically vulnerable patients. This trade-off deserves explicit consideration in policy debates.

VHA patients are predominantly male and may not generalize. CUD diagnosis depends on provider recognition and coding, which may have changed over time. DiD estimates were modest, suggesting other factors (commercialization, attitudes) also drive CUD increases. Cannot distinguish between legalization increasing CUD vs increasing detection.