In the wake of a string of Canadian military suicides, Gov. Gen. David Johnston says the military pays "substantial" attention to mental health issues in the armed forces.

Speaking to CTV's Power Play, Johnston, the commander-in-chief of the Canadian Forces, said Canada devotes the most resources per person to its military to cope with mental health issues compared to all other NATO members.

"The attention to mental health issues is very substantial in our armed forces," he said.

The issues of post-traumatic stress disorder and mental illness among soldiers was recently thrust into the spotlight after four apparent military suicides occurred within one week earlier this month in different parts of the country.

A recently released publication from the Library of Parliament on mental health in the Canadian Forces showed nearly 27 per cent of deaths of former male soldiers were from suicide, while for women about 14 per cent of deaths of former Canadian Forces members were from suicide.

Johnston said all members of the armed forces have been affected by deaths.

"Whenever there's a suicide, that's something that hits us right in the stomach," he said.

Johnston is a little more than three years into his five-year term as the Queen's representative in Canada, and he describes his experience as a "wonderful adventure."

Speaking to CTV's Don Martin, Johnston said he finds the health of the 87-year-old Queen "remarkable."

"I'm just so struck by how devoted she is to her responsibilities and how robust she is," he said. "In the last 18 months we've been at two or three different ceremonies -- she was on her feet for a very long time, always gracious and very attentive to everything that's going on."

Looking forward to the remainder of his term, Johnston said he's focused on a new social marketing campaign, called My Giving Moment, that’s aimed at encouraging Canadians to donate more of their time or money.

"Canadians are generous people, but we are a changing society and we're also a society were volunteer efforts are being done by a smaller number of people and increasing hours," he said.