At least 26 patients have absconded from Perth’s Murray Royal Hospital this year.
In response to a Freedom of Information request, NHS Tayside refused to say exactly how many patients had gone missing since January. It said this was to maintain patient confidentiality.
However, the board admitted there had been 55 instances of patients wandering off between January and November this year.
It said that 25 patients had absconded on fewer than five occasions and fewer than five patients had left the hospital on more than five occasions, although it would not give exact figures.
However, it is known that one patient went missing on six occasions in this time frame as well as absconding once in December of the previous year. On at least two occasions the patient was pulled from the River Tay in an exercise involving police and the fire service, and on another he crossed train lines in a bid to evade police officers.
Serious concerns were raised about security at Murray Royal when in November two patients kicked down doors to escape from the hospital in less than a minute.
The pair were eventually traced more than two miles away at Perth bus station. They were about to board a bus when police caught them.
NHS Tayside also declined to reveal how long each patient was missing as the information is contained in confidential patient records.
Local MSP Liz Smith has previously called for a review of security at the 186-year-old site, but her call has been dismissed by Health Minister Alex Neil.
She said there was continued unease about the number of patients going missing from the hospital.
“There is no doubt that there is ongoing concern about security at the Murray Royal and whether some of the patients who are going missing, especially those who have gone missing on several occasions, are a danger to the public,” the Conservative MSP said.
“We know the views of the emergency services, who feel that their own work has been made more difficult by the risks they are having to take to ensure patient safety.
“I raised these issues some time ago with the health secretary and I know these are issues which concern him too and which he will be discussing with the new chief executive of NHS Tayside.”
Police have said the public are vital in finding patients when they go missing.
Ms Smith added: “In many cases the person missing is away for a very short time, sometimes a day or so, or even a matter of hours.
“Public support is crucial to the success of any missing person inquiry, as information that the police force receives as to possible sightings of the whereabouts of a missing person is very often the key to finding that person quickly and safely.”
An NHS Tayside spokeswoman said patients in some areas of the hospital were allowed to leave on their own.
She said: “Murray Royal Hospital has had a low secure unit for over 20 years. Although patients within this unit are detained in hospital, they are sometimes required to attend other hospital or dental appointments off site, and it is also a routine part of their rehabilitation programme to have accompanied and unaccompanied visits outside of the hospital to education and work placements.
“The decision regarding whether a patient is allowed outside access is made based on a clinical assessment.”