More information is needed on the positive and negative health effects of marijuana, according to a new report released January 12, 2017 by the National Academies of Sciences, Engineering and Medicine. Marijuana is now approved for medicinal or recreational use in 28 states plus the District of Columbia, but federal government restrictions have made it difficult to conduct rigorous research on the drug.
For the new report, a committee led by Marie McCormick, Sumner and Esther Feldberg Professor of Maternal and Child Health at Harvard T.H. Chan School of Public Health, examined more than 10,000 marijuana studies. They found that the much of the current body of evidence does not provide any clear guidelines regarding populations that may benefit or be harmed by marijuana, or on the effects of different dosages and delivery mechanisms.
The committee did report some conclusive findings. On the plus side, marijuana has been shown to ease chronic pain and chemotherapy-induced nausea in cancer patients. But other substantial evidence suggests that marijuana can negatively affect fetal development among women who use marijuana during pregnancy. It is also linked with greater risk of chronic bronchitis and other worsened respiratory symptoms.
The overall lack of evidence-based information poses a public health risk, according to the committee. In a Los Angeles Times article, McCormick said, “What do we really know for sure? Mainly it’s anecdotes or very poor evidence.”
Read Los Angeles Times coverage: Experts have only a hazy idea of marijuana’s myriad health effects, and federal laws are to blame