How Common Is Cannabis Use Among Primary Care Patients in a Legal State?
In Washington State primary care clinics, 15.3% of patients reported past-year cannabis use and 3.1% used daily, with rates reaching 36% among 18-29 year olds and 32% among young men who smoked tobacco.
Quick Facts
What This Study Found
This study analyzed cannabis use screening results from 22,095 primary care patients in Washington State, one of the first states to legalize recreational cannabis.
Overall, 15.3% reported any past-year cannabis use and 3.1% reported daily use. These rates were substantially higher than national averages at the time.
Age was the strongest predictor: 36% of patients aged 18-29 reported any cannabis use and 8.1% reported daily use. Among the youngest patients, behavioral health factors dramatically increased daily use rates. Young men aged 18-29 who also used tobacco had a 25.5% daily cannabis use rate, and those who screened positive for depression had a 31.7% daily use rate.
The study demonstrated the feasibility of routine cannabis screening in primary care, with 74% of eligible patients completing the screening question.
Key Numbers
22,095 patients screened (74% completion). 15.3% any past-year use. 3.1% daily use. Ages 18-29: 36% any use, 8.1% daily. Young men with tobacco use: 25.5% daily cannabis use. Young patients with depression: 31.7% daily cannabis use.
How They Did This
Observational cohort study of 29,857 adults visiting primary care clinics with annual behavioral health screening (March 2015 to February 2016). Cannabis use was assessed with a single-item frequency question. Depression, alcohol, and other drug use were also screened. Electronic health records provided tobacco use and behavioral health diagnoses.
Why This Research Matters
This is one of the first large-scale assessments of cannabis use among primary care patients in a legalized state. The high rates among young adults with behavioral health conditions highlight the need for integrated screening and intervention in primary care settings.
The Bigger Picture
As more states legalize cannabis, primary care settings become a critical point for identifying problematic use. This study provides a model for integrating cannabis screening into routine behavioral health assessment and identifies the patient subgroups most in need of attention.
What This Study Doesn't Tell Us
Single-item screening may miss nuances of use patterns. Patients seen in one health system in Washington State may not represent other populations. The study occurred shortly after recreational legalization, and patterns may have changed since. The 26% who did not complete screening may differ systematically from completers.
Questions This Raises
- ?Has daily cannabis use increased further in Washington State since 2016?
- ?Do primary care patients who use cannabis daily benefit from brief interventions?
- ?Should cannabis screening trigger different clinical responses depending on the patient's age and mental health status?
Trust & Context
- Key Stat:
- 31.7% of young adults with depression reported daily cannabis use
- Evidence Grade:
- Large observational study with validated screening in real-world clinical settings. Moderate because it provides strong descriptive data but cannot establish causation.
- Study Age:
- Published in 2017, with data from March 2015 to February 2016.
- Original Title:
- Frequency of Cannabis Use Among Primary Care Patients in Washington State.
- Published In:
- Journal of the American Board of Family Medicine : JABFM, 30(6), 795-805 (2017)
- Authors:
- Lapham, Gwen T(10), Lee, Amy K(3), Caldeiro, Ryan M(2), McCarty, Dennis, Browne, Kendall C, Walker, Denise D, Kivlahan, Daniel R, Bradley, Katharine A
- Database ID:
- RTHC-01427
Evidence Hierarchy
Watches what happens naturally without intervening.
What do these levels mean? →Frequently Asked Questions
How common is cannabis use among doctor's patients?
In this Washington State study, 15.3% of primary care patients reported past-year cannabis use. Among 18-29 year olds, the rate was 36%, and daily use was 8.1% in that age group.
Is cannabis use linked to depression?
Young adults who screened positive for depression had a 31.7% rate of daily cannabis use, compared to much lower rates in those without depression. Whether cannabis contributes to depression or vice versa cannot be determined from this study.
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Cite This Study
https://rethinkthc.com/research/RTHC-01427APA
Lapham, Gwen T; Lee, Amy K; Caldeiro, Ryan M; McCarty, Dennis; Browne, Kendall C; Walker, Denise D; Kivlahan, Daniel R; Bradley, Katharine A. (2017). Frequency of Cannabis Use Among Primary Care Patients in Washington State.. Journal of the American Board of Family Medicine : JABFM, 30(6), 795-805. https://doi.org/10.3122/jabfm.2017.06.170062
MLA
Lapham, Gwen T, et al. "Frequency of Cannabis Use Among Primary Care Patients in Washington State.." Journal of the American Board of Family Medicine : JABFM, 2017. https://doi.org/10.3122/jabfm.2017.06.170062
RethinkTHC
RethinkTHC Research Database. "Frequency of Cannabis Use Among Primary Care Patients in Was..." RTHC-01427. Retrieved from https://rethinkthc.com/research/lapham-2017-frequency-of-cannabis-use
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.