In 1988, when a young woman living in Toronto named Tema Conter was randomly attacked, raped and murdered by a parolee, Vince Savoia was the first paramedic on the scene.

What Savoia saw that day disturbed him so deeply, he began having nightmares, flashbacks and panic attacks.

He didn't realize it at the time, but he had developed PTSD, or post-traumatic stress disorder – a condition that affects a greater proportion of first responders such as paramedics and firefighters, yet still goes unacknowledged by many.

Sevoia is now retired and has dedicated himself to making the public aware of the problem of PTSD among emergency workers. He says PTSD is often discussed in the context of soldiers, but the prevalence of the condition is actually higher among prison workers and paramedics.

Research has shown that several branches of public safety workers will be diagnosed with PTSD sometime in their career, including:

25 to 26 per cent of correctional officers

22 per cent of paramedics

16.5 per cent of firefighters

9 to 12 per cent of police officers

5 per cent of military members

Despite its prevalence, Savoia says there's still a stigma about coming forward. Many responders hear stories about colleagues who have sought help only to be ostracized or ridiculed. Those stories make others reticent to ask for help when they become overwhelmed by their experiences on the job.

"What we try to preach is, it takes a lot of strength to come forward and you should not hesitate to come forward," he said.

Kevin Davison, a volunteer firefighter and paramedic from Nova Scotia, says many don't realize that going to work in emergency response is as emotionally draining as it is physically demanding.

"We go to many calls where we don't see the norm. We see tragic things. Basically, we can see them a couple of times a day," he said.

"When we arrive to the scene of a major accident, it's similar to a war scene."

Davison recently wrote and recorded a song called “When Those Sirens are Gone,” to pay tribute to first responders dealing with PTSD. The song includes a line about not being about to "unsee the things you've seen."

Davison says for him, that's the hardest part of his job.

"You don't just go home and say, 'I'm just going to forget about it and not think about the child that just died in my arms," he said.

"It's something that really affects you and you need to work through that. And some people are having a really hard time doing that."

It's for that reason that Sevoia started a charitable foundation for first responders. Twelve years after that emergency call in 1988, Sevoia went back to the Conter family to ask if could launch a trust in Tema's memory to help other paramedics.

What began as a scholarship fund for paramedic students, has now grown into the Tema Conter Memorial Trust, a hub for research on first responder health issues and peer support services for the men and women serving in Canada’s first responder community.