Marijuana Use and your health

What is happening with marijuana in Colorado?

In November 2012, Colorado voters legalized marijuana for use by adults over age 21 by voting to add Amendment 64 to the Colorado Constitution. Working to understand changes in marijuana use patterns and marijuana related health effects in Colorado is ongoing.

There are 3.7 million adults over the age of 21 in Colorado and 12.7% report using marijuana. Now that marijuana is legal for use by these adults, it is important to know how marijuana may affect people, both now and in the future. All ages have the potential to be at risk for harmful health effects resulting from marijuana use or abuse. Youth, pregnant and breastfeeding women have a higher risk of harmful health effects than non-pregnant adults. When marijuana products are not locked away and stored correctly, children can be at risk for accidental use. While a few health effects have sufficient evidence to make public health statements, scientific based evidence is limited on many questions about the effects of marijuana use, and there may be both beneficial and harmful effects that are not well studied.

What should I know?

In 2014, a committee was formed to review research on marijuana health effects – the Retail Marijuana Public Health Advisory Committee. This committee wrote public health statements that are plain language translations of the major findings from the research they reviewed. The following are some of these public health statements.

• There is no known safe amount of marijuana use during pregnancy.

• THC (Tetrahydrocannabinol) can be passed from the mother’s breast milk, potentially affecting the baby.

• Legal marijuana access is associated with increased numbers of unintentional exposures in children which can lead to hospitalizations.

• Regular marijuana use by adolescents and young adults is associated with impaired learning, memory, math and reading achievement, even 28 days after last use.

• These impairments increase with more frequent marijuana use.

• Marijuana use by adolescents and young adults - even occasional use - is associated with future high-risk use of alcohol, tobacco, and other drugs like cocaine, ecstasy, opioids and methamphetamine.

• Starting marijuana use during adolescence or young adulthood is associated with future marijuana addiction.

• Marijuana use by adolescents may be associated with low academic achievement, such as not graduating from high school or attaining a university degree, lower income, and more unemployment.

• It is important to delay consuming another THC-containing product until the effects from the first edible serving are known. For new or occasional users, it takes up to 4 hours to reach maximum blood levels of THC and potentially longer to feel the full effects of consuming a marijuana edible product.

• Regular use of marijuana is associated with depression and may be associated with other mental health disorders such as anxiety and psychosis.

• Heavy use of marijuana is associated with impaired memory, persisting a week or more after quitting.

• Marijuana smoke, both firsthand and secondhand, contains the same cancer-causing chemicals as tobacco smoke.

​More information on the public health statements

Who is at risk

All ages have the potential to be at risk for harmful health effects resulting from marijuana use or abuse. Youth, pregnant and breastfeeding women have a higher risk of harmful health effects than non-pregnant adults. Unintentional use by children is also a concern. When marijuana products are not locked away and stored correctly, children can be at risk for accidental use.

How can risk be reduced?

As with most substances, retail marijuana use comes with some risk. Reducing or stopping use will greatly reduce your risk of harmful health effects. How is marijuana usage tracked?

The Tracking Network uses data from surveys that ask adults, children and adolescents specific questions about marijuana use. Some surveys ask the same questions to people in other states so that answers can be compared nationally. Answers to survey questions (data) are collected, analyzed and often compared by state, county, gender, age group, race and ethnicity. The surveys used include: Behavioral Risk Factor Surveillance System (BRFSS), Healthy Kids Colorado Survey, Pregnancy Risk Assessment Monitoring System (PRAMS), and Colorado Child Health Survey (CHS).