How legal recreational cannabis affects teens' use and health

Assessing the Impact of Cannabis Legalization on Adolescent Cannabis Use and Cannabis-Related Health Conditions

NIH-funded research Kaiser Foundation Research Institute · NIH-11306554

This project looks at whether California's recreational cannabis laws changed how often teens use cannabis and whether that led to more health problems.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionKaiser Foundation Research Institute NIH-funded
Lab location1 site (Oakland, UNITED STATES)
Project IDNIH-11306554 on NIH RePORTER

What this research studies

From a teen's point of view, researchers are using nearly 900,000 adolescents' medical records from Kaiser Permanente Northern California between 2015 and 2023 to see changes in cannabis use and related health visits. They compare trends before and after state legalization using a quasi-experimental interrupted time series design and also examine differences across local rules like retailer limits, advertising rules, and taxes. The team will link home addresses to retailer locations and map local policies to understand whether proximity or local regulations affect teen use or harms. Outcomes include self-reported cannabis use screening, cannabis use disorder, emergency visits, accidents, respiratory and mental health problems, and other cannabis-related conditions.

Who could benefit from this research

Good fit: Ideal candidates are adolescents aged 12–20 who receive care in Kaiser Permanente Northern California and have routine cannabis screening and a home address on file.

Not a fit: Those who are not Kaiser Permanente Northern California members, live outside the study area, are outside the 12–20 age range, or lack screening/address data are unlikely to be included or benefit directly.

Why it matters

Potential benefit: If successful, results could guide local and state policies and help doctors, schools, and families prevent teen cannabis harms.

How similar studies have performed: Earlier studies of legalization and teen use have been smaller or inconsistent, so this large, detailed EHR and local-policy analysis is relatively novel and more comprehensive.

Where this research is happening

Oakland, UNITED STATES

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.