“Many of pot’s effects are tangled in contradictory research, but there are a few clear health risks to consuming the drug. Smoking cannabis regularly can cause bronchitis-like symptoms, and research published last month found that chronic cannabis users, defined as people who used pot at least four times a week for more than three years, had impaired pancreatic function. There have also been cases of daily cannabis users developing pancreatitis without having any other obvious risk factors.
Regular pot use has also been associated with higher rates of depression, anxiety and poorer life outcomes like being unemployed, but causality has not been established because other factors could predispose someone both to using cannabis and having a mental illness or not having a job.
There’s also evidence that cannabis can be dangerous when used in certain situations, like during pregnancy or while driving a vehicle. A recent study linked increasing rates of childhood leukemia to an increase in cannabis use, and a separate study found a correlation between women using cannabis while pregnant and their children having higher rates of anxiety. There’s also evidence that using pot while pregnant can lead to lower birth weights, although that evidence is still considered limited. And driving a car while high has been shown to moderately increase the risk of getting into a motor vehicle accident.
Addiction can be an issue as well. Some people who smoke pot develop what’s called cannabis use disorder (CUD), a clinical diagnosis of problematic and uncontrollable cannabis use. There’s evidence that CUD rates have increased since 2008, but Dr. Kevin Hill, an addiction psychiatrist and professor at Harvard Medical School, told FiveThirtyEight in an email that “it is still important to point out that most people who use cannabis don’t have a problem with it.”
The 2020 NSDUH found that 4.1 percent of people ages 12-17 met the criteria for CUD,1 13.5 percent of people ages 18 to 25 had the disorder, and 4 percent of people over age 26 had the disorder. Yet those numbers were below rates of alcohol use disorder across all age groups in 2020’s survey.
Deborah Hasin, an epidemiologist at Columbia University, said she is very concerned about adults’ increasing use of cannabis because CUD is associated with poorer quality of life, cognitive decline and impaired educational and occupational employment. Hasin’s research has found that 19.5 percent of people who use cannabis met the criteria of CUD in their lifetimes.
“It’s clear that not everybody who smokes marijuana has all of these problems, but the risk is there, and it’s a greater risk than people assume,” Hasin said.
Using cannabis frequently increases the risks of developing CUD, and frequent pot use is growing among adults. Monthly use for 26-to-34-year-olds has more than doubled since 2008, and the share of people getting at least five days a week increased from 5.8 to 13.8 percent between 2008 and 2019, according to NSDUH survey results.”
“A 2016 study that followed a group of New Zealand adults for 20 years found that cannabis use was associated with worse gum health, but better cholesterol levels, lower BMI and reduced waist circumference.
Those results were further substantiated in a 2020 study that looked at cannabis use among people over the age of 60. Cannabis users in the study exercised more often and had a significantly lower BMI than non-users.
While there’s evidence that BMI, which measures only weight and height, is not the best way to gauge health for people who are normal weight or are slightly overweight, very high BMI scores are significantly associated with mortality.”