Legalizing marijuana has proven harmful to child health.
New research has revealed that since medical marijuana was legalized in Colorado about three-and-a-half years ago, more than a dozen young children have been unintentionally poisoned by the drug.
About 50 percent of the cases were caused by children eating marijuana-laced cookies, brownies, sodas or candy.
In at least some of the poisoning instances, the marijuana came from supplies kept by the children's grandparents, investigators reported.
"We are seeing increases in exposure to marijuana in young pediatric patients and they have more severe symptoms than we typically associate with marijuana," said lead researcher George Sam Wang, a medical toxicology fellow at the Rocky Mountain Poison and Drug Center in Denver.
But, since doctors aren't generally unfamiliar with the signs of marijuana poisoning, which, in children, can include sleepiness and balance problems while walking as with other drugs, unless the adults responsible for the children admit pot was involved, it can take considerable time and testing for medical teams to diagnose the problem, said Wang.
Wang and the other study authors asserted there are likely many more cases of marijuana poisoning left unreported because of a lingering social stigma "associated with medical marijuana --- families may be reluctant to report its use to health care providers," the study said.
"We hadn't seen these exposures before the big boom of the medical marijuana industry," said Wang. "We are seeing more symptoms because some of these products have very high amounts of marijuana in them...You get such a high dose on such a small child, the symptoms are more severe."
Medical marijuana typically contains higher-than-average concentrations of tetrahydrocannabinol, the drug's key chemical, said the study, which was published online May 27 in the journal JAMA Pediatrics.
As with similar poisonings, treatment for medical marijuana generally involves providing supportive care and waiting until one's system clears itself of the drug, said Wang, who added the children known to have been poisoned recovered quickly and didn't "need more than a day or two of hospitalization...there were no deaths or lasting side effects."
Wang's team compared the number of children treated in the emergency room for marijuana poisoning before and after the legalization law was enacted in October 2009 and found 1,400 children under 12 were evaluated for accidental poisonings in the one hospital -- 790 before Sept. 30, 2009, and 588 after.
After the law kicked in, it was determined 14 children -- mostly boys and some as young as 8 months -- ingested marijuana. Eight had consumed medical marijuana directly and seven ate marijuana in foods. Two of the children were admitted to the intensive care unit.
The report originated from one hospital in Denver, so Wang and his colleagues didn't learn about similar statistics elsewhere.
Colorado adults are allowed to possess up to 1 ounce of marijuana or six marijuana plants, according to the study, and in 2010, Denver issued more than 300 sales tax licenses for marijuana dispensaries