For some, signs of post-traumatic stress were present as soon as they returned from the Afghanistan mission. Horrific nightmares and flashbacks plagued the war-battered soldiers and kept them from sleeping. They were short-tempered and skittish, and many withdrew into isolation, pushing loved ones away. Fourteen were diagnosed with PTSD, according to their families and documents obtained by The Globe, while a coroner’s inquiry identified the mental illness in one other case. In another 10, families saw signs of PTSD, but the illness wasn’t diagnosed. In some instances, soldiers didn’t seek treatment because they feared it would affect their careers.

Their suicides came shockingly soon. Eight of the 12 killed themselves within a year of arriving home, raising questions about the thoroughness of their post-deployment health screening and the psychological support offered. Private Thomas Welch took his life a mere three months after returning from Kabul in 2004. The young infantry soldier from Northern Ontario is the first Canadian Forces member to die by suicide after serving in Afghanistan, The Globe’s investigation uncovered. For him and four other soldiers among the dozen, the dangerous deployment was their only overseas tour. All but two of the 12 had no mental-health issues before joining the military, their families said.

Multiple Afghanistan tours traumatized some troops. Canada’s involvement in Afghanistan began in 2001, not long after the Sept. 11 attacks against the United States rattled the world. The Afghanistan conflict is still raging, but Canada pulled its troops out in March, 2014, after losing 158 soldiers in the theatre. More than 40,000 Canadian Forces members served on the mission, many more than once. It was the country’s largest deployment of soldiers, sailors and air-force personnel since the Second World War. Master Corporal Charles Matiru went to Afghanistan four times, first as an infantry soldier and then with a secretive intelligence unit. His mental health worsened with each tour, his family said. He killed himself 18 months after his last deployment.

When the 1st Battalion of the Royal Canadian Regiment, based at CFB Petawawa, arrived in Kandahar in 2010, the clock was already ticking down on Canada’s combat operation. The battle group and hundreds of other Canadian troops were part of Task Force 1-10, rotation 9, which was in theatre from February, 2010, until October that year. Canada had taken over military responsibility for the volatile southern province in August, 2005. Once in the Taliban stronghold, Canadian military casualties dramatically climbed.

Among the 31 suicides examined by The Globe, participation in the Task Force 1-10 deployment emerged most often. It’s unclear why, but the insurgency was still strong, corruption remained rampant, and security was fragile. Corporal Justin Stark’s war journal offers some insight. “You just never know when one step could be your last,” he wrote a month after arriving in Kandahar. He didn’t know if he would make it to his leave.

A federation of six republics, Yugoslavia began tearing apart in 1991, as regions declared their independence and a brutal civil war erupted. A United Nations peacekeeping operation formed and Canada sent over tens of thousands of troops until leaving the Balkans in 2004. Canadians monitored ceasefire lines and secured routes for humanitarian supplies. But they also witnessed numerous atrocities as the conflict dragged on. For many Canadian soldiers, their difficult Balkan tours were followed by deployments to explosives-riddled Afghanistan. Retired Sergeant Paul Martin served four times in the former Yugoslavia before heading to Kandahar in 2008. A military inquiry into his suicide found that he was showing signs of PTSD before his Afghanistan tour.

Most military members who deployed to Afghanistan are still in the Forces, but the number grows smaller each year. As more battle-scarred soldiers are released, it will become increasingly important to monitor their transition and to understand how many are taking their lives, why and when. But suicides of former military personnel are not regularly tracked in Canada and won’t be for at least another year. Yet there are lessons to learn from each death: In the case of retired Private Tyler Hulme, his parents say he was facing a four-month wait for a civilian psychiatrist after his medical release from the military. The wait troubled the young, ill veteran and his parents, who both served in the Forces. “What am I supposed to do?” his mother recalled him desperately asking. One month after his military discharge, Pte. Hulme overdosed on prescription medication.