The spread of COVID-19 in the United States has prompted extraordinary, although often untested, steps by individuals and institutions to limit infections. Some have worried that "the cure is worse than the disease."

Economists Anne Case and Angus Deaton mocked this as a "pet theory about the fatal dangers of quarantine." They concluded in the summer of 2020 that "a wave of deaths of despair is highly unlikely" because, they said, the duration of a pandemic is measured in months, whereas the underlying causes of drug abuse and suicide take many years to accumulate.

But unlike in previous recessions, a lot changed in a short period of time last spring. Personal income increased by record amounts while the majority of the unemployed received more income than they had when they were working. At the same time, many of the usual ways to spend money, especially on activities related to entertainment or just "keeping busy," were shut down. Vacations or dining out or anything group-oriented, such as going to sports games, concerts or bars, were eliminated. That left the sorts of things that people can do by themselves.

For many people, screen time, exercising, cooking and other activities fill their pandemic days. But a few also abused alcohol and drugs. In economics terms, regardless of what happened to the street price of illegal drugs, those drugs became cheap compared to many of the normal alternatives. Patients suffering pain may also have less access to physical therapy during a pandemic, and some of them look for some relief from illegal drugs. Others would normally have attended treatment programs that were no longer conducted in person during the pandemic. All else being the same, these forces point toward more drug abuse.

Drug abuse may be more dangerous when it occurs in isolation. A person who overdoses on opioids has a better chance of survival if the overdose event is observed by a person nearby who can administer treatment or call paramedics. This danger could discourage drug use a bit, but the net effect would likely be more deaths from drug abuse even if, notwithstanding the aforementioned pecuniary factors, the amount of drug abuse was somewhat reduced.

I have examined some of the preliminary data on the causes of death during the first three quarters of 2020, including data from the Centers for Disease Control and Prevention (CDC) and from two medical examiners from large counties. Mortality in 2020 significantly exceeds what would have occurred if official COVID-19 deaths were combined with a normal number of deaths from other causes. The demographic and time patterns of the non-COVID-19 excess deaths (NCEDs) point to deaths of despair, especially drug overdose, rather than an undercount of COVID-19 deaths. The flow of NCEDs increased steadily from March to June, and then plateaued. They were disproportionately experienced by working-age men, including men as young as ages 15 to 24.

Deaths were below normal before March 2020, primarily for the elderly due to a mild flu season last winter. The trend for fatal drug overdoses had often been upward even before the pandemic and was expected to continue to some degree as fentanyl, an especially deadly opioid, inevitably found its way into new localities. Nevertheless, actual non-COVID deaths in 2020 appear to be above the previous trend. The available data are not yet complete enough to indicate whether rates of fatal opioid overdose during the pandemic were 10 percent above the prior trend, 60 percent above, or somewhere in between. It is also possible that COVID-19 deaths have been underestimated beyond my undercount estimates.

Presumably, social isolation is part of the mechanism that turns a pandemic into a wave of deaths of despair. But the results so far do not say how much, if any, comes from government stay-at-home orders versus various actions that individual households and private businesses have taken to encourage social distancing. With "the cure" having so many elements, my data do not yet identify which ones have proven to be fatal for thousands of people.

Casey B. Mulligan, professor of economics at the University of Chicago, served as chief economist of the White House Council of Economic Advisers from 2018 to 2019. His new book, "You're Hired! Untold Successes and Failures of a Populist President," explains how federal policies from both parties have helped fuel the opioid epidemic.