Public Health Effects

Picture of a babies mouth and hand eating a gummy bear
  • Summary of Research
  • Highlights
  • Edible Cannabis Exposure in Children Under 6


Recreational cannabis use and ED visits related to psychosis or schizophrenia.

Population / Location:



As recreational dispensaries per 10,000 residents increased, there was no significant association with the rate of schizophrenia ED visits per capita (incidence rate ratio or IRR: 0.95, 95% CI [0.69, 1.30]) while the rate of psychosis visits increased 24% (IRR: 1.24, 95% CI [1.02, 1.49]). Increases were for those 26+.

Exposure to high potency (> 10mg THC) products could be a driving factor in increased rates of psychosis-related ED visits.


Wang GS, Buttorff C, Wilks A, Schwam D, Metz TD, Tung G, et al. Cannabis legalization and cannabis-involved pregnancy hospitalizations in Colorado. Prev Med. 2022;156:106993


Recreational cannabis legalization, traffic collisions and fatalities.

Population / Location:

Systematic review of nine studies conducted in the US.


Six of the nine studies found a positive association between cannabis commercialization and collision fatalities – particularly those using difference-in-difference designs.

Because of overall weak methodology across studies, the authors conclude there is only a moderate probability of a causal association between cannabis availability and traffic fatalities.


Vingilis E, Seeley JS, Di Ciano P, Wickens CM, Mann RE, Stoduto G, et al. Systematic review of the effects of cannabis retail outlets on traffic collisions, fatalities and other traffic-related outcomes. Journal of Transport & Health. 2021;22


Broad range of societal costs and benefits of legalizing medical and recreational cannabis.

Population / Location:

Systematic review of 113 articles published since 2010.


Medical and recreational marijuana legalization provides both benefits and negative outcomes but with inconclusive or mixed results in some areas.

Among the negative consequences: increased adolescent use; decreased time on educational activities among adolescents.

Among the positive effects were decreases in opioid prescriptions and opioid overdose mortalities.

Studies did not show an increase in traffic fatalities or criminal activity, pre- and post-legalization nor were there clear effects on use of other drugs including alcohol and tobacco.


French MT, Zukerberg J, Lewandowski TE, Piccolo KB, Mortensen K. Societal costs and outcomes of medical and recreational marijuana policies in the United States: A systematic review. Med Care Res Rev. 2022:1-29.


Opioid mortality rates by race-ethnicity and cannabis legalization.

Population / Location:

Analysis of CDC WONDER data from all 50 US states 2010-2020.


Evaluated the marijuana protection hypothesis (availability of marijuana reduces deaths from opioids) based on findings from earlier studies (Powell et al. 2018, etc.).

Did not find support for the marijuana protection hypothesis – no evidence for a reduction in either all opioids or fentanyl death rates overall or by race/ethnicity. Instead this study found the converse - marijuana legalization is associated with worsening of opioid mortality rates especially among non-Hispanic blacks and Hispanics.

But the authors add this caveat: To the extent that the opioid epidemic may have become worse because of marijuana legalization, it is likely that the opioid mortality acceleration is due more to other factors such as the increasing availability of and lower cost of fentanyls and other non-prescriptions opioids, the increasing despair of Americans that began before the pandemic and has become worse during it, and the drug culture of the U.S. in general.


Bleyer A, Barnes B, Finn K. United States marijuana legalization and opioid mortality epidemic during 2010-2020 and pandemic implications. J Natl Med Assoc. 2022;114(4):412-25


There has been a 1375% increase nationally since 2017 in pediatric edible cannabis exposures.


The number of Illinois Poison Control Center contacts where cannabis ingestion was involved increased dramatically for children ages 1-11 years old between 2019 and 2021.


The large majority of pediatric poison control center contacts (77.0%) were owing to ingestion of edible cannabis products whereas other age groups were more evenly divided between dried cannabis plant-based products and edibles.


Although the absolute numbers are small, especially compared with EMS runs for opioid overdoses, there was a relatively large increase in the number of such runs were the primary or secondary diagnosis was for cannabis poisonings among those 26 or older, a more modest increase for those 18 to 25 years of age, and a consistent trend for those 17 years of age or younger. The number of pediatric cases (11 or younger) has remained low.


There has not been an increase in cannabis-related fatalities in Illinois from 2015-2020.


The rate of self-reported driving under the influence of cannabis increased for those 26+ older between 2018-2019 and 2019-2020. There has been an overall increase in the number of Illinois residents driving under the influence of cannabis in the last few years.


The factors associated with a positive Cannabis Drug test result among Illinois drivers in fatal crashes include being Black-non-Hispanic, being of a younger age group (particularly 16- 34 years old) and testing positive for another drug class, particularly MDMA/ Hallucinogens.


Black, non-Hispanics had a 50% higher odds of a positive test result compared with White non-Hispanics. Persons who tested positive for stimulants, MDMA or another hallucinogen, or tranquilizers also had significantly higher odds of a positive cannabis test result. Persons over the age of 45 had significantly lower odds of a positive cannabis test result as did persons testing positive for opioids.


About 30% of persons using cannabis in the past year said they experienced 1 or more adverse effects with the most common being panic reactions, feeling faint or dizzy, and nausea or vomiting.

There has been a 1375% increase nationally since 2017 in pediatric edible cannabis exposures. The most common days of pediatric exposure was Saturday and Sunday and the least frequent days were Monday and Tuesday.

Acute toxicity and admission are going up when comparing pre-pandemic and pandemic years (2017-2021). It is unknown if this is due to increased potency or a larger amount was consumed during the pandemic.

  • Pediatric ED Visits due to Cannabis Poisoning
  • Edible Cannabis Exposure in Children Under 8
  • Poisoning by Age
  • Type and Multi-Poison Control Contacts
  • EMS Runs for Cannabis Poisoning by Age Group
  • EMS Runs for Cannabis Poisoning by Race
  • EMS Runs for Cannabis Poisoning by County
  • Patient Characteristics Associated with EMS Cannabis Poisoning Runs
  • Drug-Related Overdose Fatalities Citing Cannabis as a Contributing Cause of Death
  • Self-Reported Driving Under the Influence of Substance by Age Group
  • Testing Results for Drivers in Fatal Crashes by State and US
  • Factors Associated with a Positive Cannabis Drug Test Result among Illinois Drivers in Fatal Crashes
  • Percentage of Cannabis Users Experiencing Any Adverse Effects in the Past-Year