They are as perplexing as their acts are violent and shocking: young people born and bred in the relative comfort of a prosperous Western society who adopt a brutal, extreme and foreign ideology.

Unconfirmed reports have implicated another Canadian-bred Muslim extremist in the deadly assault on the heart of the country’s democratic system Wednesday.

If true, it would amplify difficult questions about how such violent zealots are created — and what can be done to stop them before they strike out.

What’s known about homegrown terrorists is muddy. Evidence suggests they are no more likely to have psychiatric problems than others, but seem to be searching for some kind of personal meaning, or a morbid brand of immortality or, simply, adventure, various experts say.

And the most difficult to comprehend — Canadians who convert first to Islam and then to extremism — are likely targeted by recruiters for groups like ISIS, said Muhammad Robert Heft, a convert himself whose group P4E tries to defuse radicals.

“New Muslims are like sponges, they take in all this information so quickly, so they can get confused really easily,” he said. “And they’re not culturally set in their ways so they’re easier to work on. They’re more susceptible to these recruiters.”

Dozens of Canadian extremists are believed already overseas fighting with Islamist extremist groups like ISIS or Somalia’s Al-Shabab and another 90 have been identified by the RCMP and CSIS as eager to join them. Martin Couture Rouleau, shot dead after running over two Quebec soldiers Monday and killing one of them, was on the list. The man behind Wednesday’s shooting of a sentry at Ottawa’s War Memorial and armed assault on the Parliament Buildings has been identified as Michael Zehaf-Bibeau, also reportedly among the “high-risk travellers” identified by police.

And yet even when suspects come to light, officers say there is only so much they can do to prevent violent behaviour in someone who has committed no crime. They had visited Mr. Rouleau on Oct. 9, leaving convinced that he was moving away from extremism and unable to take other action.

One exception was Mohamed Hersi, a 28-year-old immigrant from Somalia sentenced in a Toronto court to 10 years in prison in July for attempting to join a terrorist group. In that case, an undercover officer was able to record incriminating statements.

The answer for others may lie, not so much with visits from police, but with engagement by religious peers and leaders — before the homegrown radical becomes a homegrown terrorist, some experts say.

“So far, we’ve been very reactive, as opposed to preventive,” says Jocelyn Belanger, a psychologist and expert on radicalization at University of Quebec at Montreal. “We have to ensure that members of our community are well integrated.”

Mr. Heft said he has managed to turn around many of the youth he works with, saying his personal background makes him better equipped to challenge the beliefs of misguided young extremists than imams, symbolic leaders who can be “clueless” about what drives radicalized youth.

Encounters with police and intelligence agencies, on the other hand, only encourage their warped sense of victimhood and identity with terrorists, he said.

A new program being developed by the York Region Police near Toronto seems promising, Mr. Heft said. The force is actively involving the myriad ethnic and religious groups in its community to help head off radicalization, said Insp. Ricky Veerappan.

But what motivates a Canadian — born Muslim or otherwise — to adopt a lifestyle that seems not only reprehensible, but so alien to the prevailing culture?

At the University of Waterloo, sociologist Lorne Dawson is embarking on a study of homegrown radicals he hopes will fill in some of the gaps.

What little evidence exists now indicates terrorists generally are no more likely to suffer from psychological problems than the general population, he said. As for the homegrown variety, some are second-generation immigrants struggling to find a place between their parents’ culture and Canadian society. Adhering to a dogmatic ideology might give them the direction they seek, said Prof. Dawson, noting that not all young people are craving freedom.

In fact, “there is a whole group to whom that is totally perplexing and frustrating,” he said. “They don’t want that. They want structure and order. They want a clear vision.”

Research that Prof. Bélanger and colleagues have done with Tamil Tigers and extremists in Jordan and the Philippines point to a single, overarching motivation, what the academics call the “quest for personal significance,” leading them to join a community they believe gives their lives meaning, and adopting its ideology in an effort to be accepted.

“When, for instance, [they feel they are] not important, they don’t matter, they are a speck of dust in some kind of uncaring universe, it increases psychological pain,” he said. “One way of assuaging this negative feeling is connecting through a group.”

That connection might occur in person or, in the case of “lone-wolf” radicals, through online correspondence with an extremist overseas, like ISIS members who have posted propaganda videos on the Internet, said Prof. Belanger. Once hooked, the home-grown radical may be willing to sacrifice his own life – as well as take others’ – thinking “they will have more in death than they had in life.”

Mr. Heft has observed what seems like a similar phenomenon. The radicalized youth he encounters often seem dissatisfied with their existences, he said.

“These are not sacrificing anything for Allah … they’re sacrificing for attention,” said Mr. Heft. “They’re not happy with their lives. They’re not doing what they want to do. A lot of them are depressed. A lot of them are doing this as an indirect suicide.”