WISCO was not available for comment on Thursday.
However, Xu and his family believed that Xu's diagnosis was a false one and was merely a means to silence him.
An initial medical test at Guangzhou Psychiatric Hospital on April 22, paid for by Xu's family, showed that Xu only suffered from depression, the New Express reported. A further diagnosis was recommended but became impossible after his capture.
Gong said she and her husband signed off on the diagnosis in Wuhan because they had been promised Xu would be released quickly and were threatened with imprisonment for Xu if they refused, the paper said.
Xu's parents have been denied permission to visit Xu in the ward since 2006, the report said.
"This man (Xu) is not supposed to stay here. But we have been ordered to keep him," Chen Zhonghua, a medical staff member with WISCO's No. 2 Workers' Hospital told the Southern Metropolis.
Wang Sijing, a reporter with the Guangzhou-based 21st Century Business Herald, told the Global Times on Thursday that, according to neighbors, WISCO staff had taken Xu's parents away on Tuesday afternoon and they have been missing since then. Wang said she herself had been forcefully taken away and locked up for two hours Wednesday night in an attempt to investigate Xu's case in Wuhan.
Zhang Zanning, director of the health law research center at Southeast University, said "Law enforcement officials are not entitled to confine mentally ill patients unless they pose a danger to the public."
It is not clear in the current law whether police are required to obtain family members' permission or an authorized diagnosis before they take action, Zhang told the Global Times.
"As a result, abuse of power by some law enforcement officials occurs and the rights of mental patients and their families are violated."
He said that the condition Xu was diagnosed with is not dangerous and sufferers posed no threat to the public.