One-third of adults in the United States report are experiencing symptoms of anxiety or depression as a result of the coronavirus disease 2019 (Covid-19) pandemic, a study published Friday by JAMA Network Open found.

In addition, 30 percent percent said they suffered from stress related to the pandemic and the lockdown measures put in place to contain the spread of the virus, the data showed.

Just under 12 percent indicated that they have contemplated suicide since the start of the pandemic, the researchers said.

Although most of those who reported mental health problems related to the global crisis had a history of “psychiatric” diagnoses, more than 15 percent of them did not, according to the researchers.

“These findings underscore the broad impact that the pandemic … has had on peoples’ lives,” study co-author Mark Czeisler said.

“We’re rapidly approaching 500,000 Covid-19 deaths, which has an impact on those individuals and their loved ones. … Beyond that there are challenges related to caregiving, access to medical care and of course mental health,” said Czeisler, a Fulbright Scholar at the Turner Institute for Brain and Mental Health of Monash University in Australia.

Researchers have documented a rise in mental health disorders across the country since the start of the pandemic, including a significant increase in cases of depression.

These issues have been attributed to concerns about the potentially life-threatening virus as well as the social isolation and economic hardships brought on by lockdown measures such as business and school closures.

The findings are based on a survey of more than 5,100 adults from the United States conducted in September 2020, according to Czeisler, who is also a researcher in psychiatry at Brigham & Women’s Hospital in Boston.

This study was a follow-up to a similar survey of nearly 5,500 U.S. adults in June, as part of the ongoing Covid-19 Outbreak Public Evaluation, an assessment of the mental health nationally led by researchers in academia and others with the US Centers for Disease Control and Prevention, he said.

Essential workers, or those who continued to report to their jobs, even at the height of the pandemic, such as healthcare and supermarket workers, were most likely to report mental health problems related to Covid-19, the researchers said.

Nearly 50 percent of respondents who identified as essential workers reported having symptoms of anxiety or depression due to the pandemic, while 46 percent indicated that they experienced stress, the data showed.

Just under 27 percent of responding essential workers said they had thoughts of suicide because of Covid-19 and its effects on their lives, the researchers said.

Among all respondents, 15 percent reported increased substance use due to pandemic-related stress, according to the researchers.

“Optimistically, I hope that these trends motivate substantial efforts to address mental health now, but also beyond the Covid-19 pandemic,” Cziesler said.

“On the other hand, if unaddressed, the mental health effects of the pandemic could be with us for a long time, particularly with young adults,” he said.