One unexpected benefit of medical marijuana legislation appears to be a decrease in painkiller overdoses, perhaps because some chronic pain patients are turning to cannabis instead of powerful opioid drugs. In states with laws legalizing medical marijuana, new research shows there are nearly 25 percent fewer deaths from painkiller overdoses. Opioid painkiller overdoses are a growing problem nationwide. More than 16,500 Americans died of opioid drug overdoses in 2010, and the numbers continue to rise. Although a casual relationship hasn’t been proven, there appears to be a significant association between marijuana legislation and a fall in overdose deaths. Researchers from...