A nurse called the 24-hour hotline to complain about a constant headache. A doctor said he was feeling ostracized by the public, even as he worked to save patients from the epidemic. One caller said she was feeling suicidal.

The volunteers at Yong Xin Kang Yi (“Use your heart to fight the virus”), a crisis line established for the overworked, overstressed medical staff on the front lines of the coronavirus outbreak in China, listen to it all.

“Our principle is just to be emotionally available for them,” said Erjing Cui, 28, a psychotherapist who volunteers for the hotline from Seattle, where she lives. “The most important thing that we’ll try to do is to provide a space and listen and provide empathy to what they have to say.”

Ms. Cui is one of many mental health professionals trying to address the emotional burden of the epidemic, which has subjected doctors and nurses to extreme hardships while rattling the nerves of ordinary people around the globe. In China alone, hundreds of hotlines have been set up by universities, local governments and mental health organizations to help people cope.