Hospital visits and poison center calls involving children unintentionally exposed to marijuana rose sharply in Colorado after the drug was legalized for recreational use, according to a study published on Monday by JAMA Pediatrics. University of Colorado pediatrician George Sam Wang and his co-authors report that the number of patients younger than 10 who were seen at Children's Hospital Colorado in Aurora for symptoms related to inadvertent cannabis consumption rose from an average of eight in 2012 and 2013, the two years before state-licensed marijuana stores began serving recreational consumers, to an average of 16 in 2014 and 2015. During the same period, the average number of marijuana-related calls to the Rocky Mountain Poison and Drug Center involving children in the same age group rose from about 18 to about 43.
Marijuana still accounts for a minuscule share of emergency room visits and poison center calls for children 9 and younger: about 0.6 percent and 0.2 percent, respectively, in 2014-15, compared to 0.4 percent and 0.1 percent in 2012-13. Furthermore, the harm suffered is usually not serious. Most of the patients were not admitted, and among those who were the median stay was 26 hours. Just 3 percent of the poison center calls involved "major" effects. The most commonly noted effects at the hospital were drowsiness and dizziness, although agitation, vomiting, rapid heart rate, muscle rigidity, seizures, and respiratory depression were occasionally reported. The median age of the children in both data sets was around 2, and marijuana edibles were the most commonly reported source.
These increases may be partly due to parents' increased willingness to report marijuana exposures now that the drug is legal as well as increased awareness among hospital staff. But it seems likely that the upward trends are also related to the easier availability of marijuana products, especially edibles, such as candy, cookies, and brownies, that might appeal to toddlers and preschoolers. Wang and his colleagues note that "almost half of the patients seen in the children's hospital in the 2 years after legalization had exposures from recreational marijuana [as opposed to medical marijuana, which was available from dispensaries in Colorado before 2014], suggesting that legalization did affect the incidence of exposures." Taking a longer view, the authors find that poison center calls rose by an average of 34 percent a year between 2009, when medical marijuana was commercialized, and 2015, the second year of recreational sales, compared to a national increase of 19 percent a year. The difference was statistically significant, adding to the evidence that commercial production of marijuana edibles makes them more common in Colorado homes, thereby increasing the opportunities for ingestion by children who mistake them for ordinary snacks.
As I note in my latest Forbes column, regulators in Colorado and Washington have responded to this problem by mandating warning labels, requiring child-resistant packaging, and restricting the kinds of edibles that can be legally sold. Each of these safeguards has its limitations. When existing warning labels identifying edibles as marijuana products did not eliminate unintentional consumption, both Colorado and Washington required more conspicuous labels, but it's not clear they will have a noticeable impact. Wang et al. note that child-resistant packaging "is a deterrent and does not guarantee that a child is unable to open the container," so it is "not a substitute for proper safe storage." They also point out that "child-resistant packaging only functions when the product is kept in the original packaging and the child-resistant system remains intact with repeated package access."
Colorado has taken the further step of banning edibles shaped like animals, people, or fruits, while Washington forbids any marijuana product "designed to be especially appealing to children," including "gummy candies, lollipops, cotton candy, or brightly colored products" but not baked goods, chocolate bars, soda, or savory snacks, all of which are allowed. The effectiveness of those rules is doubtful, while broader bans would seriously impinge on the freedom of adults who prefer edibles and invite a resurgence of the black market, which has neither child-resistant packaging nor warning labels.
Regulatory solutions can go only so far in addressing this problem, which is ultimately a matter of parental responsibility. Among the patients at the children's hospital in Aurora, parents were the main source of the marijuana, followed by grandparents or other relatives and neighbors, friends, and babysitters. The poison center data indicate that the marijuana product was outside its original packaging in 9 percent of cases and improperly stored in another 34 percent. Those records are incomplete, since the center did not always ask for such details, and the actual percentages are surely much higher. When a 2-year-old eats a pot cookie, it seems safe to assume an adult screwed up.