Calls to poison control double after medical marijuana legalized in Massachusetts

Cannabis plant
Calls to poison control in Massachusetts increased after medical marijuana legalization. (Brent Barnett, Pixabay)

Legalizing medical marijuana in Massachusetts appears linked to uptick in calls to poison control for kids.

Researchers at the University of Massachusetts, Amherst set out to see whether the number of children up to age 19 exposed to cannabis changed after the legalization of medical marijuana in Massachusetts.

According to records from the Regional Center for Poison Control (RPC) and Prevention, the number of calls more than doubled from about 29 calls annually in the four years prior to legalization to about 69 calls annually in the four years after.

Published in JAMA Network Friday, the study looked at 218 calls to RPC over eight years involving cannabis exposure to children, representing 0.15% of all calls in that age group. Incidents rates during the time period went from 0.4% to 1.1%, a 140% increase.

RELATED: Study: Most patients who use medical marijuana use it for pain

While those numbers are small, they are statistically significant, researchers said.

"The increasing prevalence of exposures to concentrated and edible cannabis products and decrease in exposures to plant material is concerning because of the increased potency of these product types," authors said in the study. 

The highest frequency of calls were related to teenagers, ages 15 to 19, with calls for this age group rising from 29 to 69. But among children aged 0 to 4 years, a statistically significant increase was observed in the incidence of exposures to edible products after the legalization of medical marijuana.

As a result, researchers suggest that states legalizing medical marijuana should consider regulations to prevent exposure among young children, with particular attention to edible cannabis products and concentrated extracts.

The results of these RPC calls were moderate medical outcomes for 154 cases, 70.6%. No deaths were reported. A higher proportion of serious outcomes (2.5%) was observed among cases involving polysubstance use, compared with cases involving only cannabis.

To date, cannabis has been legalized for medical use in 33 states, and for adult-only use in 11 states. Previous data from Colorado and Washington show that the number of cannabis-related calls for children ages 0 to 9 rose steadily after medical dispensaries proliferated and use was legalized for adult recreational purposes.

RELATED: Pot 101—Doctors lack knowledge about medical marijuana

And for older kids, aged 10 to 19 years, urgent care and emergency department visits related to cannabis increased in Colorado between 2005 and 2015.

Medical marijuana became legal in Massachusetts in 2012 and the first dispensaries opened in 2015. The state does require childproof packaging and warning labels.

“Follow-up studies should assess whether Massachusetts, like Colorado and Washington, may see a continuing increase in pediatric cannabis exposure cases as implementation of commercial, adult-use cannabis sales continues. States that have not revised their cannabis laws do not appear to be experiencing increases in cannabis exposure,” the study concluded.