Where does research on marijuana stand?

Marijuana has been legalized, decriminalized or medicalized in over half of U.S. states, but no accepted standards exist to inform decisions about how to use it safely. 

To help inform future public health efforts, the National Academies of Sciences, Engineering, and Medicine conducted an in-depth review of the health effects of marijuana from existing research dating from 1999 through August 2016. The report was sponsored by a group of federal, state and nonprofit groups, including Truth Initiative®.

We have compiled some highlights that relate to tobacco use from the nearly 400-page report:

• Many of the same risk factors for tobacco use are implicated in marijuana use: being a young adult, African-American, male and having a lower income. Use is most prevalent among young adults between the ages of 18 and 25, of which nearly 20 percent report using marijuana in the past month.
• Smoking cigarettes is a risk factor for the “progression to problem marijuana use,” which is defined as having a marijuana use disorder, or hazardous or risky use. Symptoms of a marijuana use disorder include craving, withdrawal, lack of control over use, and social or interpersonal consequences from use.
• During adolescence, frequency of nicotine use is a risk factor for the development of problem marijuana use.
• There is some evidence of an association between using marijuana and developing dependence or abuse of substances, including tobacco, alcohol and illicit drugs.

There are many areas for future research, some of which are specifically relevant to tobacco:

• Studies have yet to quantify the exact effects of inhaling tobacco and marijuana at the same time.
• There is a need for more long-term studies to understand the physical, mental and psychosocial health effects of marijuana use.
• The measurement of marijuana use varies across studies—from daily, to weekly, to monthly use—making comparisons of marijuana’s health effects and associations with tobacco use difficult to interpret.
• More research is needed to understand the impact of using marijuana and tobacco at the same time on mental health and other substance use behaviors, particularly among younger age groups.

Read the full report for more findings, including information about the steady increase in use since 2007, evidence about its therapeutic effects for some health conditions, and an association with mental health conditions.

For more information about Truth Initiative’s position on marijuana and tobacco, read our policy statement.