Marijuana Use by the Numbers

As of this writing, the medicinal use of marijuana is legal in 33 states, the District of Columbia, and three U.S. teritories. Of those states and territories, 14 also allow recreational use of marijuana. An additional 13 states allow the sale of products containing cannabidiol (CBD), with restrictions on the amount of THC (see definitions in sidebar). However, at the federal level, marijuana is classified as a Schedule 1 drug and is therefore illegal, although the FDA has approved certain components of cannabis for therapeutic purposes.2

37.6 million
Number of users in the U.S. in 2016, making marijuana the most commonly used illegal drug in the country.1

Adult Users in the U.S.

Percent who use marijuana primarily for recreational purposes3

Percent who use pot purely for medicinal purposes

Percent who use pot for both medicinal and recreational purposes

Daily Users

Compared to non-users, daily cannabis users are much more likely to have a psychotic episode, including schizophrenia:

3.2 times
the greater likelihood for all daily cannabis users

4.8 times
the greater likelihood for daily users of high-potency cannabis4

Teen Users

According to a survey of 44,482 eighth, tenth, and twelfth graders in both public and private schools in the U.S.:5

—Percent who had used marijuana daily in 2018:
• 8th graders: 0.7%
• 10th graders: 3.4%
• 12th graders: 5.5%

—Percent who had vaped marijuana in 2017 and 2018, respectively:

• 8th graders: 1.6%—2.6%
• 10th graders: 4.3%—7.0%
• 12th graders: 4.9%—7.5%

percentage of high-school seniors in 2014 who thought marijuana was harmful, down from 54% in 2009.

Statistical Correlations

Changes in healthcare utilization in Colorado since pot was legalized there:6

increase in motor vehicle accidents

increase in alcohol abuse and overdoses that resulted in injury or death

decrease in hospitalizations for chronic pain

2.8 times
increase in calls to poison control centers due to children accidentally ingesting a cannabis-containing product compared to states where recreational pot is not legal.7

Effects of Starting Young

Marijuana users have poorer cognitive and executive function compared to non-users. This was most pronounced in people who started in their teens.8

• Frequency: People who started using marijuana before age 16 smoked pot 1.75 times as often as people who were over 16 when they started. The former also smoked 2.5 more grams per week.

• Addiction: Of those who started using pot before age 18, 1 in 6 became addicted to it; of those who started after age 18, 1 in 10 became addicted.9

• Escalation: 12-to-17-year-olds who vape are 4.3 times more like to use marijuana as those who don't vape.10

• Psychoses: Among teens who smoke pot, 14 in 1,000 are likely to develop psychoses, including schizophrenia; among those who don't smoke it, only 7 in 1,000 are likely to develop psychoses.11

1. "Marijuana and Public Health," CDC (2017):
2. "State Medical Marijuana Laws," National Conference of State Legislatures (as of July 2, 2019):
3. The Health Effects of Cannabis and Cannabinoids, The National Academies of Sciences, Engineering, and Medicine (2017):
4. The Lancet: Psychiatry (May 1, 2019):
5. "Monitoring the Future 2018 Survey Results," NIH, National Institute on Drug Abuse:
6. BMJ Open (May 2019):
7. Ibid., note 3.
8. J Stud Alcohol Drugs (March 2016):
9. Ibid., note 2.
10. "Teen vaping tied to marijuana use," Reuters (Aug. 13, 2019):
11. "Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study," BMJ (Mar. 1, 2011): This is for teens that are not necessarily prone to psychoses based on family history and who did not show symptoms of psychoses at the beginning of the 10-year study.


A general class of plants from which hemp and marijuana are derived. Though the word "cannabis" is sometimes used synonymously with marijuana, there are over 400 chemical components in the cannabis plant.

THC (tetrahydrocannabinol)
The main psychoactive chemical in cannabis, responsible for producing marijuana's "high"; its concentration in any given marijuana product can vary widely.

CBD (cannabidiol)
A non-psychoactive ingredient in the cannabis plant that may have analgesic properties. It is legal in some states, so long as it is derived from hemp, but it is also sold in various products that are not FDA-approved and whose safety has not been tested.

Considered a non-psychoactive strain of cannabis; hemp must contain no more than 0.3% THC; otherwise it is legally treated as marijuana according to the 2018 Farm Bill. Hemp is used to manufacture such products as rope, paper, and other textiles as well as for producing CBD products.

has an M.S. in chemistry from the University of Texas at Dallas, and an M.A. in bioethics from Trinity International University. She resides in Dallas and currently works as a freelance science writer and educator.

This article originally appeared in Salvo, Issue #51, Winter 2019 Copyright © 2020 Salvo |