TORONTO -- When retired soldier Jacqueline Buckley sees her four-year-old grandson get angry, she can't help but think of her own capacity to explode with rage. She also thinks of the fury that can be unleashed by his mother, her daughter.

The former sergeant believes this is the legacy of her post-traumatic stress disorder, a harrowing psychological wound she was diagnosed with in 2009. She suspects it is buried deep in her family tree.

She notes that her own military dad was a stoic man who refused to discuss what he did during postings to Germany and Cyprus. Their cold relationship was not unlike the one she would forge with her own kids.

"I knew he loved me but I don't think I ever felt it," says Buckley, who lives in Carstairs, Alta.

Now she frets over the fate of her daughter's hyperactive toddler, a rambunctious boy who she suspects may have behavioural issues, as well as his 12-year-old half-sister.

Buckley believes they're hobbled by a rocky childhood in which their young mother fell in and out of violent relationships and became addicted to oxycodone and heroin.

Buckley blames part of those struggles on her own poor caregiving skills, which she says went south in 1998. She was part of a grisly mission to analyse dental remains of the victims of Swissair Flight 111, the airliner that smashed into the Atlantic Ocean a few kilometres from Peggys Cove, N.S., killing all 229 people on board.

At the end of a long day at the morgue, Buckley -- who was a single mom at the time -- would go home, have a bath and cry. Her daughter was aged 10 but Buckley says she "just checked out" as a mother.

"I was home but I wasn't there," she says, admitting she "was probably a very mean parent."

"Looking back, I know I love my children but I didn't know how to feel love. I was cold. I had no emotion at all and if I did have an emotion it was probably anger," says Buckley, who was medically released from service in 2010.

As the years went on, her anxiety grew "and anger became huge." She had trouble sleeping, pursued toxic relationships, suffered unexpected odour-based flashbacks, and obsessed over indelible memories of human remains.

Today, Buckley suspects her children and grandchildren are mirroring some of her symptoms, believing they suffer from a condition sometimes referred to as vicarious trauma, compassion fatigue, or secondary PTSD.

Experts define this as the emotional duress that results when someone hears about the first-hand trauma of another person and experiences symptoms that mimic PTSD. It can also affect professionals such as psychotherapists, child welfare workers, emergency personnel or addiction counsellors.

Greg Lubimiv of the Phoenix Centre for Children and Families near Garrison Petawawa says it's a growing problem for military families, especially as a new generation grapples with the legacy of their parents' multiple deployments to Afghanistan, the longest war in Canadian history.

"We've had examples where a young person has become suicidal, we've had cases where children have become depressed, where children have become very disrespectful of authority, just very angry inside and not really be able to explain what's going on with them," says Lubimiv, whose centre serves about 1,500 people per year, about 25 to 30 per cent of them from military families.

"We've had parents who become very impatient, who become very threatening to their children, very angry with the children. And this is all ... a result of being overwhelmed by emotion, which can happen to any of us in a stressful situation."

He recalled the case of an eight-year-old who was a fairly good student until he punched another child. Therapy revealed he feared for the safety of his soldier father in Afghanistan but felt he couldn't talk about it with his mother because she refused to discuss the war.

"His interpretation of that was his mom was being very vulnerable. Her interpretation of him was he was very vulnerable. And it ended up with nobody communicating. And then in the end, it all became a volcano inside of this child."

It's generally understood that children of traumatized people are at increased risk for mood and anxiety disorders but the impacts are far more extensive than previously thought, says Rachel Yehuda, director of the Traumatic Stress Studies division at the Icahn School of Medicine at Mount Sinai in New York City.

She studied the children of Holocaust survivors and pregnant women who survived the 9/11 attacks and found that traumatic events can actually change the way genes respond to the environment, and that those changes can be passed on to the next generation.

"What epigenetics is saying is that events have the ability to evoke change, deep change, not just transient change. But they have the ability to alter the way the body functions," says Yehuda.

But that's not necessarily a bad thing, she adds.

"If you're a biologist, you have to believe that at least some of that adaptation is meant to be positive," she says. "It means that our efforts to create positive environments may yield positive changes."

Increasingly, Yehuda finds herself searching for meaning in a terrible event: she prefers to view trauma not as the enemy but as an inevitable part of life that people must prepare for.

"There are so many people that have said, 'If not for the fact that I was challenged in this way, I might not be able to be empathic, or see pain in others, or find the solutions for what we can do to build and rectify,"' she says.

"The best we can hope for is that when challenges are thrown our way that we believe we have the tools for transformation and adaptation."

Right now, it's not automatic that a PTSD diagnosis also includes screening for the family but "increasingly, the recommendation is that it should be," says Dr. Patrick Smith of the Canadian Mental Health Association.

Smith says this is an issue he's pressing as he serves on the mental health advisory committee for Veterans Affairs Minister Kent Hehr, who is tasked with creating a new "centre of excellence" in veterans' mental health care.

The plan is to include a training component that could help various disciplines -- be they social workers, psychologists, teachers or psychiatrists -- learn about vicarious trauma.

Buckley says that understanding is sorely needed, recounting her frustrating battles to secure intensive therapy for her daughter.

"Families need so much more than I think they realize and I don't think they actually get it," she says.

But at least Buckley says she feels better equipped to confront a cycle of trauma in her family.

"I can't fix what has been but I can move it forward as best as I can, knowing now what I know."