The paper called for greater efforts to prevent and lessen the impact of mental illnesses and for improved mental health services at medical institutions and other places, including schools, universities and work places, by 2030.

"Because of the more intense pressure of life in an era of accelerated economic and social transformation, the number of people in China with mental health issues keeps rising year after year, resulting in obvious social problems," the commission said.

At Sunofus, an online forum in China for people with depression, the number of registered members has reached 130,000. Most of them have been diagnosed with depression and are undergoing treatment, according to Mo, who helps to manage the forum.

Most people visit the forum for medical advice, such as seeking the right drugs and how to reduce the side effects of their medication, he said.

"They also communicate and vent their complaints. Here, they find they have met comrades and are not alienated, as they feel they are in society," he added.

Du Xia, a psychiatrist who specializes in the diagnosis and treatment of depression at Beijing Huilongguan Hospital, a leading center for the treatment of depression and mental health issues, said the number of people with depression in the capital is rising. Du receives more than 10 patients on average during each half-day shift, twice as many as 10 years ago, and most of them are women.

More than 90 percent of the patients who consult Du already have serious conditions, and some have repeatedly attempted to take their own lives, she said.

According to research conducted in several hospitals in Shanghai, only one in five people with depression is given a correct diagnosis by non-psychiatric specialist, she said.

"It is very difficult to diagnose depression, even for psychiatrists, because patient may display many different symptoms," she added.

In addition to the most-frequent symptoms, such as loss of appetite, sustained low spirits and loss of interest in life in general, depression can also manifest itself via physical illness such as headaches and diarrhea, she said.

"Patients with these symptoms most likely go to see doctors who specialize in internal diseases, which can often lead to an incorrect diagnosis."

The lively personalities and optimism displayed by some patients may also be deceptive. "Some of my patients look very active and outgoing. But they may become very pessimistic during depressive episodes, as if they have become a different person. According to what they have told me, they feel entirely hopeless, helpless, and the whole world becomes gray," she said.

Zhang Juyi, a psychiatrist at Beijing Anding Hospital, said the exact cause of depression is still unknown, but research suggests that it may be inheritable because people who have close relatives with depression are more likely to have the condition.