For adults in California aged 65 years and older, there has been a significant increase in cannabis-related emergency department (ED) visits, an adverse effect of cannabis use, according to study findings published in the Journal of the American Geriatrics Society.

The legalization of cannabis for medical and recreational purposes in many states has led to a significant increase in cannabis use among older adults in the United States. Psychological changes related to aging, increased comorbidity, and medication use place older adults at high risk for adverse effects of psychoactive substances. Cannabis use can cause acute physiologic changes that can exacerbate pulmonary and cardiovascular morbidities, and potential cannabis-related drug interactions can lead to adverse effects. The aim of investigators was to evaluate trends in cannabis-related ED visits in California.

The investigators conducted a retrospective cohort study trend analysis of cannabis-related ED visits of older adults from all nonfederal acute care hospitals in California using data from the Department of Health Care Access and Information from 2005 through 2019. They used primary and secondary ICD-9 and ICD-10 codes to identify cannabis-related ED-visit diagnoses of nondependent abuse or unspecified use, dependence, or poisoning. The current study data represent unique ED encounters.

Continue Reading

Investigators determined the cannabis-related ED visit rate per 100,000 ED visits for adults at least 65 years of age per year and stratified by age groups (65 to 74, 75 to 84, 85 years and older). Additional subgroups included sex, race/ethnicity, Charlson comorbidity index score, and health insurance.

Investigators found a significant increase in the cannabis-related ED visit rate in California for adults aged at least 65 years and all subgroups (P <.001). In 2005 there were 20.7 per 100,000 visits. This increased dramatically to 395.0 per 100,000 ED visits in 2019 (relative increase 1804%). Older men had a higher ED visit rate in 2019 and a greater absolute increase in the ED visit rate vs older women. Older women had a larger relative percent increase (2375.8% vs older men 1531.3%). Older Black adults experienced the highest ED visit rate in 2019 with the largest absolute increase compared with other races/ethnicities.

A higher ED visit rate in 2019 was found among older adults with a higher Charlson score vs older adults with lower comorbidity scores. This subgroup had a larger absolute increase during the study period. By age group, adults aged 65 to 74 years had the highest ED visit rate in 2019. Adults aged 75 to 84 years had the largest relative percent change (2208.3% increase).

Compared with older adults with health insurance, older adults without health insurance had the highest ED visit rate in 2019 and the largest relative increases (3099.3%).

Investigators noted “cannabis abuse and unspecified use” defined nearly all cannabis-related ED visits each year (relative increases 1844.2% vs other categories defining ED visits).

Significant study limitations include the transition from ICD-9 to ICD-10 problematic in trend analysis, inability to differentiate the type of cannabis used, route of use, or distinction between medical vs recreational use. Additional limitations include the capture of ED visits and not individuals, clinician reporting bias, and data limited to the state of California. The study does not include Veterans Administration facilities and the results are not generalizable outside of California.

Investigators concluded, “The need for acute medical care is an adverse effect of cannabis use among older adults and is increasing sharply in California.” They wrote, “Given the higher risk for adverse effects related to cannabis, all older adults, regardless of health status, should be regularly asked about their use of cannabis and assessed for problematic use.” They urge that routine medical care for older adults include education and discussion of cannabis use in the context of health.


Han BH, Brennan JJ, Orozco MA, Moore AA, Castillo EM. Trends in emergency department visits associated with cannabis use among older adults in California, 2005-2019J Am Geriatr Soc. Published online January 9, 2023. doi:10.1111/jgs.18180

This article originally appeared on Psychiatry Advisor