While expressing his fears about legalization, Tony Dokoupil wrote that every "year about 375,000 people end up in the ER with marijuana-related 'averse reactions,' more than any drug other than cocaine." Mike Riggs counters:
According to the National Hospital Ambulatory Medical Care Survey (NHAMCS), the 375,000 instances in which marijuana is noted in an ER visit are not necessarily instances in which marijuana caused an "averse reaction." Rather, the survey tells us that in those 375,000 cases, marijuana was "commonly involved in an emergency department visit." So, if you smoked a joint on Tuesday, and on Thursday you blew a tire in your work vehicle and careened into a guard rail, then had your blood drawn at the ER, marijuana was involved in your emergency room visit. While people do ocassionally get so high that they call for an ambulance, the NHAMC survey doesn't distinguish between people who go to the ER with drugs in their system, and people who go to the ER because of the drugs in their system.
Riggs also tosses grains of salt at the marijuana rehab numbers Dokoupil cites. Kleiman pushes back here.