WHEN THE PANDEMIC seized New York, Dr. Lorna Breen, a 49-year-old emergency room doctor who worked at New York-Presbyterian Allen Hospital and Columbia University Medical Center, found herself in the trenches alongside physicians toiling through 18-hour days and sleeping in hospital hallways.

When Breen contracted COVID-19 herself, she took a week and a half off, only to suffer from exhaustion once she went back to work. Her family brought her to stay with them in Virginia, where Breen seemed detached, according to her father. She was also deeply disturbed, he said, after witnessing so much death and suffering of patients. On the last Sunday in April, Breen was rushed to the hospital with self-inflicted injuries, and later pronounced dead.

"Make sure she's praised as a hero, because she was," her father, Dr. Philip Breen, told The New York Times. "She's a casualty just as much as anyone else who has died."

COVID-19 has been associated with other suicides that drew widespread media attention, including a German state finance minister who appears to have taken his own life while worried about economic disaster, a British teenager distressed by social distancing measures, and an Italian nurse who feared spreading the virus to other people. One county in Washington state reported a surge in deaths by suicide, mostly of men in their 30s and 40s, since the outbreak began.

Researchers fear the phenomenon could become more widespread: In a commentary published last month in medical journal The Lancet Psychiatry, an international group of suicide experts advocated "urgent consideration" to prevent a rise in suicide rates, especially as COVID-19 – and its devastatating economic impact – drag on for months.