Marijuana: What We Know & What We Don’t Know

what we know about marijuana

Living here in Colorado, we are never short on news surrounding marijuana. Some days it’s good for you, some days it’s not.  So, we wanted to understand, what do we really know about marijuana? And what’s still to be determined? We interviewed Dr. Daniel Vigil, Manager, Marijuana Health Monitoring and Research Program at the Colorado Department of Public Health and Environment to find out.

9Health Fair: There’s a lot of information out there about marijuana. Some of it is legit, some of it not so much. What do we really know about marijuana?

Dr. Vigil: We’ve found a lot of scientific evidence connecting marijuana use and some important health effects.  Among adolescents, these include impaired cognitive abilities and academic performance and lower likelihood of graduating high school.  Children whose mothers used during pregnancy can have attention problems and impaired cognitive abilities.  Among adults, effects include driving impairment and increased auto crash risk, impaired memory for a week or more, and chronic bronchitis.

On the other hand, some well publicized claims do not have strong scientific evidence, including long-term memory loss or decreased long-term IQ.

9Health Fair: What about smoking it? Is smoking marijuana safer than smoking cigarettes? What about those vapor things and hookahs?

Dr. Vigil: Smoking marijuana has been strongly associated with chronic bronchitis, and more study is needed on other lung conditions.  Marijuana smoke contains many of the same cancer causing chemicals as cigarette smoke.  However, possible links between marijuana and cancer have not been adequately studied, and current evidence is mixed.  There has been little research on differences between smoked marijuana and other methods of use, such as vaping or edibles.

9Health Fair: What else don’t we know yet about marijuana?

Dr. Vigil: There is a lot we don’t know, and we’ve identified several priority areas for future research.  These include effects of use during pregnancy, whether there are differences between the effects of smoking versus other methods of use, and ​the potential ​effects of higher potency marijuana (as is now common in Colorado).

Colorado voters in 2000 accepted marijuana’s medicinal benefits for the following conditions:

  • Cancer.
  • Glaucoma.
  • HIV or AIDS.
  • Cachexia.
  • Persistent muscle spasms.
  • Seizures.
  • Severe nausea.
  • Severe pain.

CDPHE is also funding additional research in to the medicinal applications of marijuana.

Regarding secondhand marijuana smoke, there is clear evidence that it contains many of the same cancer-causing chemicals as tobacco smoke.  But human exposure to secondhand marijuana smoke has not been adequately studied to say what health effects it has.

When it comes to understanding marijuana, it’s also very important to understand the source of the information you’re reading. Check out our Topic of the Month for information on validating the latest marijuana news (or “news”).