Spending a whole month indoors with a little chance of going outside could take a toll on a person's mental health. Many in the central city of Wuhan, the epicenter of the COVID-19 outbreak, found themselves depressed, consumed by the idea of staying physically healthy. But a special hotline was ready to help.

Zhang Jiaxiu, a counselor from Wuhan Mental Health Center, received a call from a father, who got stranded in Wuhan after the city was quarantined.

The father was worried about his daughter, who lives in another city and experienced repeated headaches every time she thought of the distance between her and them.

"It's a difficult time. I understand you as a father, your wife and daughter are in a state of torment. But I assure you that we are all facing challenges," Zhang tried to calm the father.

It was a 20-minute-long conversation, but just one of over 100 calls the center receives every day.

The counselors said they have never been needed this much in the two decades since the hotline was launched. A lot of the emotions callers experienced, from distress to confusion, were due to the inconvenience brought by the lockdown.

"After one week of staying indoors, you can properly manage your time. But by the second and third weeks, you'll get bored by the repetitive routine," said Sun Ye, a psychological therapist from Wuhan Mental Health Center.

The call center recruited 200 professionals thanks to a call forwarding system supported by a tech company.

Ruan Hongwen was one of the volunteers. When she's not on shift, Ruan spends her time working with her community.

"My job allowed me to meet different people under quarantine. When it came to the hotline service, I can better evaluate their situation by listening to the tone of their voices," Ruan said.

The consultants said they may receive more calls when the outbreak ends, as people shift their attention away from the disease. They said they'll be ready for an even tougher challenge.

(Zhang Youze and Meng Mingwei also contributed to the story.)