People visiting Colorado are more likely to end up in the emergency room for marijuana use than residents of the state, according to a study published in the New England Journal of Medicine.

Recreational use of marijuana is legal in four states, including Oregon, Alaska, Washington and Colorado. It has been legal in Colorado since 2014. Since its legalization, emergency room visits have increased significantly. In 2012, before the drug was legal, 70 per 10,000 emergency room visits were related to marijuana use. In 2014, this number increased 44 percent to 101 per 10,000 visits. This number is even higher for out-of-state visitors. In 2012, there were 78 per 10,000 emergency room visits. In 2014, there was a 109 percent increase to 163 visits per 10,000.

The study found that the visitors came to the state for work or visits with family or friends and decided to try the drug. They then experienced symptoms such as anxiety, heart palpitations and gastrointestinal issues. Because they were not used to the side effects, their concerns grew enough to enter the emergency room.

Researchers on the study from Northwestern Medicine and the University Of Colorado School Of Medicine recommend education on the substance in order to reduce these visits and promote safety.