In his first public comments since the release of surveillance videos related to the prison-death case of teenager Ashley Smith, Canada's prison watchdog conceded that correctional staff still struggle with the "day-to-day practice" of looking after inmates with mental illnesses.

Speaking to CTV's Question Period Sunday, Correctional Investigator Howard Sapers said frontline prison staff are still forgetting to consider mental health issues in everyday transactions with inmates, despite the recognition that a different approach is needed.

"That's where we're seeing that some of the lessons learned are being ignored and some of the commitments of changing practice just haven't followed through," he said.

Sapers said basic promises, such as allowing mental health professionals to review serious incidents or insuring that mentally ill inmates don't spend long periods of time in segregation, are not being fulfilled.

He referenced a report his office released in September 2010, in the wake of Smith's death, examining the in-custody deaths of nine other inmates.

"What we found, quite sadly, were some very similar circumstances and patterns of behaviour," said Sapers, noting that the intent of the report was to investigate whether Correctional Services Canada had heeded recommendations related to the treatment of mentally ill prisoners.

His comments follow the release of disturbing video footage at the Ontario coroner's inquest looking into Smith's death. Smith, 19, choked herself to death in a cell five years ago at the Grand Valley Institution in Kitchener, Ont.

Video recorded in the months before her death show prison staff trying to restrain Smith and tranquilizing her against her will.

Another video shows a subdued Smith with a hood over her head as staff duct-tape her arms to an airplane seat during a transfer from a Saskatoon prison. When she complains that it hurts, they threaten to duct-tape her face.

Prime Minister Stephen Harper was said to be "horrified" by the footage, while federal officials have ordered Correctional Services Canada to fully co-operate with an inquest into her death.

Smith involved in 160 ‘use of force' cases

Though Canadians first saw the footage when it was released to the public last week, Sapers said he started reviewing videos related to the Smith case as early as five years ago -- during her incarceration.

"That's really what heightened our concern about how she was being treated and how her sentence was being managed," he said, adding that unedited footage of Smith's detention shows correctional staff responding to her with behaviour that ranges from compassionate to "completely unacceptable."

Smith was involved in a total of 160 "use of force" incidents during the 11-and-a half-months she spent in federal custody, Sapers said.

"Sometimes it was several incidents a day and it would vary depending on where she was," he added. "The incidents varied in intensity and in frequency and the responses varied in intensity and frequency."

Sapers said he's personally reviewed 10 to 12 hours of footage related to Smith's incarceration.

Sources have told CTV News that there are actually about 60 hours of video footage showing 109 incidents in which correctional staff at various institutions use force against Smith.

Some of that footage shows a guard smashing Smith's fingers with a flashlight, sources say. There is also video from a New Brunswick provincial facility of Smith being wrapped in a straitjacket and Tasered.

Guards watching over Smith the day she died said they were ordered not to enter her cell to remove anything from around her neck unless she stopped breathing.

‘We know how to do a better job'

Sapers has acknowledged that safety and security issues must be considered when dealing with inmates who self-harm. But he's also noted that forceful intervention can often serve to reinforce such behaviours as self-injury.

Last month, Sapers released a report that noted that incidents of self-injury in federal prisons have tripled in the last five years.

The report said there were 912 incidents of self-injury involving 303 offenders in 2011-12. The incidents included slashing, self-strangulation, head-banging, and swallowing harmful objects.

His investigation also noted that nearly one-third of self-injury incidents occurred when the inmate was in a segregation cell. Such seclusion can exacerbate symptoms of mental illness, it said.

"My concern extends beyond just the numbers, and goes to the response and capacity of the Correctional Service of Canada to manage prison self-injury appropriately and not primarily as security incidents," he said at the time.

In his Sunday interview, Sapers acknowledged that Correctional Services Canada has partnered with various levels of government to create a mental health strategy.

However, if that strategy isn't implemented, Sapers said he would support an inquiry into why it failed.

"I think we believe that we know how to do a better job and we should do it," he said. "Frankly, it's inexcusable if we don't."