It seems the adjustment period for legalized marijuana in Colorado is tougher for out-of-towners than it is for native residents.

A new study released Thursday in the print edition of The New England Journal of Medicine found that the number of emergency room visits related to cannabis use has risen since 2014, the first year of widespread legalization, but only significantly among visitors to the centennial state. For instance, when looking at the combined data from over 100 hospitals in 2013, the authors estimated that for every 10,000 ER visits made by out-of-towners, 112 were related to cannabis, whereas it was 87 for residents; in 2014, that number jumped to 163 for the former group, and only to 101 for the latter.

A separate analysis of ER visits at an urban academic hospital in Aurora, CO, came upon similar numbers.

"Emergency room visits related to cannabis use have increased more dramatically among out-of-state visitors than among Colorado residents," said lead author Dr. Howard Kim, an emergency medicine physician at the Northwestern University Feinberg School of Medicine, in a statement. "This may indicate that out-of-state visitors are unprepared for the adverse effects of marijuana use."

These adverse effects can include everything from an elevated heart beat to low sperm count to even temporary psychosis. For the sake of accuracy, though, the most dangerous of these dangers are exceedingly rare. Certain factors that might increase that risk are the consumption of high-potency strains, possible genetic mutations, and maybe even gender, since some research shows that male pot users are more likely to develop cannabis psychosis than women. For the current study, Kim and his colleagues came up with their own theories for the disparity.

"Anecdotally, we noticed that most out-of-towners were in Colorado for other reasons, such as visiting friends or on business," Kim said. "They ended up in the ER because they decided to try some marijuana." Conversely, since medical marijuana was legalized in 2009, in-state residents may have simply had a smoother learning curve.

Though the authors were unable to measure for it specifically, one potential lesson not yet learned by out-of-towners may have been with regards to edible pot products.

"People eating marijuana products often don't feel any effect immediately, leading them to eat another edible," Kim explained. "Then they've ingested multiple products, so when the effect finally kicks in, it is much stronger."

Rather than condemn the public’s growing desire for legalized cannabis, though, the authors simply advocate for a stronger effort at education. "Everyone needs to be aware of the side effects of marijuana use," said senior author Dr. Andrew Monte, assistant professor of emergency medicine at the University of Colorado School of Medicine. "These results underscore the importance of educating the public and especially any visitors to marijuana-legal states on safe and appropriate use of cannabis products."

As for the unfortunate ER patients? It appears that most were sent home fine as can be after a few hours.

Source: Kim H, Hall K, Genco E, et al. Marijuana Tourism and Emergency Department Visits in Colorado. NEJM. 2016.