The recreational use of marijuana was legalised in Colorado USA in 2014. 

Now, five years later, hospital emergency rooms regularly see patients admitted for unrelenting abdominal pain, nausea and extreme vomiting - Cannabis Hyperemesis Syndrome (CHS).

Hospital toxicologist, Andrew Monte, says that sufferers are not helped by normal anti-nausea medicine.

"We actually treat them with antipsychotics. That seems to be the most effective treatment," Dr Monte said.

Then there are the fatal road accidents, which have doubled in Colorado since 2014.

Amanda Hill, 24-year-old daughter of Denise and Ed Hill, drove out of their Denver driveway las June.  An hour and a half later the parents were told that Amanda was in a coma after being hit by a stoned driver.  She died three days later.

Tragically, the Hills had voted against legalisation of marijuana because of the risk of increased road accidents by stoned drivers.  Now they are living with their worst nightmare.

Adapted from “Marijuana has been legal in Colorado for five years. Business is booming, but there's a dark side” by Conor Duffy and Niall Lenihan in Colorado, ABC News , https://www.abc.net.au/news/2019-06-02/the-dark-side-of-legal-marijuana-five-years-on-in-colorado/11160420