Is legal marijuana as harmless as defenders say?

The number of American states to legalize recreational marijuana has surged in recent years, up from eight in 2017 to 18 in 2022. But as the stigma surrounding pot fades, the drug’s unintended consequences are intensifying. Most alarming is a rise in kids accidentally consuming adult cannabis-­infused “edibles.” Newly published research shows how legal marijuana today is affecting not just adults but young children.

How are kids getting marijuana edibles? It’s a combination of increased at-home use of edibles and deceptive packaging. Edibles are often packaged to look like popular candies and snacks geared toward kids, such as Nerds Rope, gummy bears, or Doritos. Edibles are also unlikely to have child-resistant packaging, making it easy for a curious toddler to take a nibble.

How much has children’s consumption of edibles increased? Using national poison center data, a Jan. 3 Pediatrics report noted a ­dramatic spike in kids under age 6 exposed to cannabis after accidentally ingesting an edible. The journal reported 207 such cases in 2017, and 3,054 cases in 2021—growth that mirrors the expansion of legalized recreational marijuana. Of those ­children who ate edibles, 91 percent did so in their own homes.

What risks do these edibles pose to children? Children are less able to handle the effects of tetrahydrocannabinol (THC), the compound in marijuana that produces a high, and are more likely to eat multiple servings. Of the 7,043 total exposures assessed in the Pediatrics report, 36 percent of patients were treated in the emergency room and 23 percent were admitted to the hospital. No children died from eating edibles, but in nearly half of the cases, the children experienced central nervous ­system depression, which can cause sleepiness, uncoordinated movements, and, in rare cases, seizures.

Do states that allow recreational marijuana use regulate the sale of edibles? Some states restrict how edibles are packaged. Michigan, Washington, Massachusetts, and Arizona forbid the use of cartoons, fruits, or any other designs that may appeal to children. Most states restrict the per-serving and per-package amount of THC in edibles.

What harmful effects have been reported for adolescents and adults who use marijuana? Extended marijuana use negatively affects cognitive function. A meta-review in Addiction last year showed that THC is associated with a decline in the brain’s executive functions, including decision-making, planning, problem-solving, and regulation of emotions. A landmark longitudinal study tracking some 1,000 participants from birth found an average 8-point decline in IQ by age 38 for participants who started using marijuana as adolescents. And marijuana smoke may cause worse lung damage than tobacco smoke, according to a November study in Radiology.