A recent research says that two-fifths of freshmen at Peking University, one of the most prestigious universities in China, thought of life as meaningless.

The revelation has attracted much attention in China. Meanwhile, it's not rare to see lethargic employees at work or hear news of suicides caused by depression.

In China, it is estimated that about 100 million people suffer from various kinds mental illnesses. Out of those people, 16 million are believed to be severely affected by their conditions.

Meanwhile, another 250 million are believed to need psychological services, with 80 million in serious need of treatment.

However, 72.3% of those with the illnesses are not even aware of their depression, anxiety or other mental problems.

Depression has become a leading cause for suicides in China.

Globally, an estimated 700 million people suffer from mental illnesses, accounting for 8% of all those with medical conditions.

The top three mental issues in the world are depression, anxiety and insomnia.

30% of American are believed to have various psychological problems.

In 2012, 804 million people killed themselves globally, with 23.9% of them from rich countries.

314 million Southeast Asians committed suicide in 2012, leading the region to have the highest suicide rate in the world.

Surveys by Chinese health authorities show that the 100 million people in the country suffering from depression include 10% of the country's total female population and around 8% of the total male population.

Every year, hundreds of thousands of Chinese people commit suicide.

A recent study has surveyed young to middle-aged employees at 50 of China's top companies in 30 cities. It showed that 78.9% of those surveyed showed signs of agitation, with 59.4% reporting anxiety and 38.6% haunted by depression.

About a third of primary and middle school students in China are believed to suffer from various forms of mental disorders, while up to a quarter of college students in the country are showing signs of mental illnesses.

Mental diseases account for about 20% of all cases of illnesses in China, but government spending on psychological issues takes up only 2.5% of all public health expenditures.

In developed countries, public spending on mental issues on average accounts for about 5.1% of all health-related expenditures. The proportion is only 0.5% in low-income countries.

During the 9th Global Conference on Health Promotion in Shanghai this year, experts agreed to regard the practice of mental health as the key to city building.

Lu Chunling from the Harvard Medical School said that her research in developing countries has led her to believe that mental issues were related to the development of an entire nation instead of a single person.

Councillor Des Cahill, Mayor of County Cork in Ireland, said that a quarter of Irish adults have mental diseases, which made heart diseases and diabetes even worse. The Irish health department developed programs to give the patients chances to do creative activities, such building things and swimming, to improve their conditions.

Here are some tips on improving mental health:

1. Keep expectations low but try your best.

2. Try to understand others when you are not happy.

3. Try relaxing activities, like listening to music and jogging.

4. Believe that you are stronger than you think you are.

5. Let go of the things beyond your control.