"My parents have become good friends with a lot of other dog owners," Jiang says. "One owns a hardware shop and helped us repair the broken tap in our bathroom."

Walking the dog every day helps her parents stay healthy, Jiang says.

Qiao Jingwen, 30, of Beijing, says that when she feels depressed at home, her two dogs run to her, rubbing themselves against her legs, and holding them makes her feel better.

Ever since she adopted the two dogs she has made her business trips shorter, ensuring that she is away for no longer than two days.

"I cannot stand leaving them for too long. All I did was give them a roof over their heads, but they have given me much, much more."

Zheng Richang, a professor of psychology at Beijing Normal University, has done research on children and pets and found that those who keep them tend to look after the weak, are less likely to feel lonely, and are more likely to become interested in or love animals. Keeping pets can better teach children responsibility and independence, he says.

"Many families have only one child, which easily makes children self-centered and poor at communicating with others. But keeping pets nurtures patience, empathy and a sense of responsibility."

Wu Jian says: "Maybe every person from a one-child family should keep a cat to cure the cancer of egotism."

In countries like Germany and South Korea, keeping pets is prescribed to help cure depression and addictions, says Tao Ran, director of the medical addiction division of the General Hospital of Beijing Military Region.

Related: The loyal and dedicated members of the cat patrol