An increase in drug- and alcohol-related deaths helped drive a decline in American life expectancy in 2021, according to two reports the U.S. Center for Disease Control released Thursday.

Unintentional injury deaths — which include accidental drug overdoses — and chronic liver disease and cirrhosis were the fourth and ninth leading causes of death across the country in 2021, according to the CDC’s annual mortality report. An increase in COVID deaths, the nation’s third leading cause of mortality, also contributed to a drop in life expectancy at birth from 77.0 to 76.4 years.

Over the first two years of the pandemic, U.S. life expectancy declined by over 3% from a high of 78.8 years.

National and local experts have reported an increase in substance abuse since COVID’s arrival, which left many users feeling stressed, isolated and without a support system.

“We’ve just sort of seen an across-the-board increase in behavioral health need and acuity,” Tom Kivler, Mid Coast Hospital’s senior director of Behavioral Health, told The Times Record in May. “What we immediately saw with people in treatment was a struggle to stay in recovery.”

More than 106,000 Americans died of drug overdoses in 2021 for an age-adjusted death rate of 32.4 per 100,000, according to the CDC’s annual report on overdose deaths. The figure marks a 14% increase over 2020 and a 135% increase from 2013 levels.

The number of deaths involving cocaine, psychostimulants like methamphetamine and synthetic opioids like fentanyl has risen rapidly in recent years, the report found.

An estimated 632 Mainers died of drug overdoses in 2021, according to researchers at the University of Maine’s Margaret Chase Smith Policy Center. Both Cumberland and Sagadahoc Counties had fewer per capita fatal overdoses than the state average.

Chronic liver disease and cirrhosis climbed into the top 10 causes of death in the U.S. in 2021, part of a larger “unprecedented increase” in alcohol-related deaths since the start of the pandemic, according to Dr. Aaron White, chief of the National Institute on Alcohol Abuse and Alcoholism’s Epidemiology and Biometry Branch.

Based on death certificates, alcohol played a role in about one out of every 10 deaths among Americans under the age of 65 in 2020, according to White. In 2021, the number of alcohol-related deaths jumped again to nearly 109,000, 37.8% higher than 2019 levels.

Mainers struggling with drug or alcohol addiction can find resources by calling 211, a 24/7 information line organized by the United Ways of Maine, the Maine Department of Health and Human Services and The Opportunity Alliance.