Is Old Mental Hospital Facade haunted?
Hong Kong Reported haunting level 4 of 5

What actually happened
From 1939 to 1961 the building served as wards for mentally ill female patients, then as a psychiatric outpatient clinic until 1971, after which it stood vacant for 27 years.
The history
Completed in 1892 as medical staff quarters for the Government Civil Hospital, only its granite facade survived the 1998 redevelopment into the Sai Ying Pun Community Complex; the facade was declared a monument in 2015.
What people report
The Antiquities and Monuments Office itself records that the building is affectionately known as the High Street Haunted House, and local tradition tells of figures and sounds from its asylum years.
That paragraph is reported tradition, not a claim about what is there. The history above it is sourced; the stories are recorded because people tell them.
Visiting
2 High Street, Sai Ying Pun, Hong Kong