Questions include whether anyone the respondent knows has ever been confined to his home because of abnormal behaviour, whether there is anyone who often fights with others or smashes objects, whether people speak in riddles, whether they speak or laugh to themselves or show odd facial expressions, and whether anyone believes that people are plotting against him.

If a person answers "yes" to any of the questions, the relevant neighbours' name, gender and address must be given, and that person will be marked as possibly having a mental disorder.

Health authorities will refer cases to the nearest branch of the Centre for Disease Control and Prevention. A person may then undergo a hospital diagnosis.

Other questions to determine mental stability include whether a person talks too much, meddles in others' affairs, is cold towards others or doesn't leave the home.

It was unclear whether filling out the questionnaire would be mandatory, and there was no mention about the possibility that misinformation could be spread through the survey.

News of the impending survey has been met largely with criticism by microbloggers.

Some people said that, based on the questions, they would be suspected of having a mental disorder because they answered "yes" to at least one question.

Others said they felt lucky not to be living in Shanghai, or they might be dragged off for electroshock therapy.

Professor Liu Xiehe , a leading mainland psychiatrist at Sichuan University's West China School of Medicine, said public objection stemmed from previous instances in which sane people were kept in psychiatric hospitals, often because authorities were trying to silence troublemakers.

Doctors have also been tied to false mental diagnoses at the insistence of authorities.

One high-profile case involved a petitioner named Xu Wu , who escaped from a psychiatric ward in Wuhan , Hubei , in April last year. He had been locked up for more than four years in a hospital affiliated with the state-owned Wuhan Iron and Steel, because he had a salary dispute with the company - his former employer.

"However, psychiatric surveys are needed, because early diagnosis and early treatment are beneficial to patients," Liu said, adding that there have been several nationwide investigations into mental disorders over the past 30 years.

Previous investigations involved health experts going to people's homes and talking with them face to face.

For the Shanghai survey, in addition to the public responses to the questionnaire, the 11 questions will be posed to community-level police officers and local residents' committees, administered by local governments.

"It is impossible to talk with every person," Liu said, noting the city's massive population.

Xue Wei , a senior psychologist with a privately-run counselling firm called Linzi Counselling in Shanghai, said the questions were also designed to inform people about symptoms commonly associated with mental disorders, to assist in early detection.

He added that the survey showed that authorities planned to provide more, and better, mental health services in future.

"Few people afflicted with mental problems take the initiative to go to hospitals. They aren't aware that they need to," Xue said. "Therefore, this survey is a necessary step to screen for potential patients."

But Huang Xuetao , a rights lawyer in Shenzhen, blasted the plan in Shanghai, saying that asking people to report their neighbours to authorities was a severe infringement on privacy. She said information collected will surely be shared with other authorities, such as the police.

The Shanghai Health Bureau did not reply to interview requests by the , but a woman in the bureau's propaganda office said that many people had called recently to ask about the survey.