Marijuana consumption is up in the United States - and so is the potency of the pot.
That's according to a new report from the United Nations, which found that legalization in four Western states, particularly Colorado, has played a role in the trend.
"The prevalence of marijuana use in Colorado is higher, and is increasing faster, than the national average," said the report.
Nationwide, the report said that pot use among those 12 years old and up has risen from 10.3 percent in 2008 to 12.1 percent in 2012, the most recent year available.
The potency of marijuana, as measured by the chemical THC, has been getting stronger, thanks to advances in growing techniques and genetically selected strains, according to the UN, which noted "growing concern about the potential of cannabis to cause serious health problems."
The UN said that since legalization in Colorado, calls to the Rocky Mountain Poison and Drug Center have doubled. Emergency room visits have also doubled for people vomiting from potent edibles or somehow burning themselves severely "from attempted THC extraction from cannabis plants."
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The report also said that cannabis is popular in many places around the world, with more than 180 million users worldwide.
"The parliament in Jamaica recently passed a law allowing for possession of 2 ounces or less, personal cultivation of five or fewer plants and the legal use of marijuana by Rastafarians for religious purposes," said the report.
Meanwhile, cocaine use has steadily declined in the U.S. between 2006 and 2013, the most recent year for available data, the UN said.
And while marijuana use has notched up 1% among high school students (to 25.8% in 2013 from 24.7% in 2012) cocaine use among high school students has been cut in half.
