ON SUNDAY, the police in Jinan, East China's Shandong province, announced the results of their investigation into the deaths of an entire family, concluding a man had killed his wife and two sons, along with his parents, before setting fire to their sixth-floor apartment and committing suicide by jumping out of the window. Hebei.com.cn comments:

The police did not say why the man killed his family and committed suicide, but there were clues in the news release, which stated that he frequently visited websites for treating depression before his death and a variety of drugs for treating mental illness were found in his desk. He also left behind pessimistic writing expressing his feelings and concerns about the future for his family.

It seems reasonable to conclude therefore that the man was suffering from severe depression. It is still not known why some people suffer such extreme depression, but the latest research shows that although depression is not hereditary, it has high possibility of inheritance.

Some genes have already proved associated with depression, and the relatives of people suffering from depression face higher risk of suffering from the condition.

But besides that, depression is also related to the environment in which one lives and grew up, for example, if someone lives in a not-so-harmonious family during childhood, or is under a lot of pressure during adulthood he or she may be prone to depression. According to data from the World Health Organization, about 10 percent of people with depression commit suicide.

Worse, some in a distorted display of love, kill their family members before committing suicide, fearing their futures will be bleak.

And the sad thing is that even those closest to them often don't know the torment of those suffering from depression. But although depression is difficult to detect and prevent, big data offers some hope that those with depression can receive proper treatment before it is too late. For example, in this case, the man had frequently visited websites on the treatment of depression. This data, if detected, could have helped the authorities realize he needed help.

However, that might involve the collection of personal data, which is against the law at the moment. We hope the legislature takes this into consideration in the future so as to prevent more tragedies like the one in Jinan.