The attack by Wu Huanming, who stormed onto the grounds of the private school in northern Shaanxi province and slashed and killed seven preschoolers and two adults, was the latest of five assaults against schoolchildren in the last two months that have left 17 dead and more than 50 wounded.
Sociologists say the recent attacks reflect the tragic consequences of ignoring mental illness and rising stress resulting from huge social inequalities in China's fast-changing society. At least three of the attackers had prior mental health histories and two committed suicide, including Wu, after the attacks.
Wu had shown signs of depression and psychosis because of worsening illnesses, including diabetes and an inflamed prostate, said Li Zhenfeng, a deputy police chief. Wu had attempted suicide twice and repeatedly told family members of his intention to kill himself, Li said.
"With these factors combined, Wu Huanming decided to take his revenge against others and commit suicide," Li told a news conference.
China's leaders have publicly acknowledged the need to do more. In the first remarks by the communist leadership, Premier Wen Jiabao said there was a need to search for the underlying causes of the violence, in addition to tightening safety measures.
"We are making serious efforts in tackling social tensions, settling disputes and improving local governments' ability to smooth things out," Wen told Hong Kong's Phoenix TV in an interview Thursday.
An editorial in the state-controlled Beijing News pushed for an examination of emerging social problems - such as unemployment, land demolition and widening gap between rich and poor - calling them "the soil that breeds extreme activities of individuals." Though the causes of the recent attacks remain unclear, experts say China has failed to adequately address the mental health needs of its citizens.
A study in the British medical journal The Lancet last year showed that about 173 million Chinese people, or 17.5 percent of the population, have some form of mental disorder, from depression to schizophrenia. The vast majority of those - about 158 million - have never received any kind of professional help.
Mental disorders account for 20 percent of the social, economic and psychological costs of illness in China - but only receive 4 percent of its health care resources, said the report's lead author Michael Phillips, director of the Suicide Research and Prevention Center at the Shanghai Mental Health Center.
In the case of the attackers, there is some evidence of a 'copycat' element, though there was no clear pattern, said Phillips, who is also professor of psychiatry and global health at the U.S-based Emory University School of Medicine.
"There's reason to believe that they are seriously psychologically disturbed and psychotic," he said.
Attacking children shows their "desire to make their statement in the strongest way possible." All the attackers in recent cases have been men in their 30s or 40s. They all used knives and hammers - unlike in the US, guns are tightly controlled in China and obtaining them is virtually impossible.
Some experts have speculated that the attackers sought to target children, society's most vulnerable members, because they cannot vent their frustrations on the government itself.
"It's a revenge-based type of action that is directed against the government," said Borge Bakken, sociology professor and director of the criminology program at the University of Hong Kong.
Psychiatrist Zheng Zhanpei from the Shanghai Mental Health Center said the stigma attached to mental illness in China prevents people from seeking help.
"It's quite common to hear discriminatory remarks like 'insane' or 'lunatic' on TV or other media. Lots of people dare not seek medication because they have concerns that they might be labeled 'mad,' " Zheng said. "They just endure their mental illness until they explode." - Associated Press Researcher Xi Yue contributed to this report.
