Is America’s weed habit dangerous?
FEW RICH countries have taken to legal weed quite like America. Although federal regulation remains tight, the drug is legal for recreational use in 24 states and for medical use in 38. One in six American adults now uses marijuana at least monthly, according to the National Survey on Drug Use and Health (NSDUH); nearly one in 20—about 11m people—gets high every day. A recent paper by Jonathan Caulkins of Carnegie Mellon University estimates that the number of “daily or near-daily” marijuana users—defined as those who report getting high on at least 21 of the past 30 days—surpassed the number of daily alcohol users in 2022.
That finding grabbed headlines. It does not mean that weed is a bigger health risk than alcohol, but it does have some worrying implications.
The first point to note is that a lot more Americans drink alcohol than get high from cannabis; drinking is a lot more dangerous. Around two-thirds of American adults have had a drink in the past year, compared with a fifth who have had a toke. More than half imbibe at least once a month. The Centres for Disease Control and Prevention reckons that the number of deaths in America that can be attributed to alcohol, either in full or in part, is now nearly 180,000 per year. The mortality risk from marijuana is virtually nil. The main danger comes from driving under the influence.
But weed users tend to indulge their habit more often. One in five marijuana users gets high every day (before legalisation by some states the figure was around one in ten). By our calculations, disregarding “near-daily users” the number of daily tokers surpassed the number of daily drinkers in 2018. Their habit may not be harmless.
Studies have shown that people who use cannabis regularly may develop schizophrenia and other psychotic disorders earlier than they might otherwise have done. Heavy users may also have an increased risk of cardiovascular diseases, including heart attacks and strokes. In an article for the Washington Monthly Mr Caulkins explained that heavy use may also harm short-term memory, concentration and motivation, resulting in “lost opportunities in schools and the workplace”.
Our analysis appears to back this up. Data from the NSDUH survey show that in 2022 just 42% of daily or near-daily marijuana users said they had “very good” or “excellent” health, compared with 53% of monthly users and 56% of yearly ones (see chart 2). Those differences remain even after controlling for demographic characteristics such as age, race and education, and excluding people who use marijuana for medical purposes. Daily pot users also tend to report worse mental health, with a larger share saying that they suffered an episode of depression in the past year.
On measures of employment the findings are less stark. Serious stoners fare only slightly worse in the workplace than more casual pot users. Working-age adults who use marijuana every day or nearly every day are only slightly less likely to be employed than are monthly users. They work roughly the same number of hours, too. But the data also show that heavy marijuana users tend to skip work more often than do casual users and non-users. They also earn less (see chart 3).
Correlation is not causation. It may be that people with lower incomes and poorer health are more inclined to become heavy pot users; or that some third factor causes all three outcomes. Whatever the explanation, the number of daily smokers could rise as legalisation becomes more common. As many as five states could legalise recreational use of the drug in 2024. Voters in Florida and South Dakota are already set to vote on the issue in November.■