After his fourth combat tour, to Afghanistan in 2011, Sgt. First Class Michael B. Lube, a proud member of the Army Special Forces, came home alienated and angry. Once a rock-solid sergeant and devoted husband, he became sullen, took to drinking, got in trouble with his commanders and started beating his wife.

“He would put this mask on, but behind it was a shattered version of the man I knew,” said his wife, Susan Ullman. She begged him to get help, but he refused, telling her: “I’ll lose my security clearance. I’ll get thrown out.” When she quietly reached out to his superior officers for guidance, she said, she was told: “Keep it in the family. Deal with it.”

And so he did. Last summer, just days after his 36th birthday, Sergeant Lube put on his Green Beret uniform and scribbled a note, saying, “I’m so goddamn tired of holding it together.” Then he placed a gun to his head and pulled the trigger.

To a growing number of medical experts and the Special Operations Command itself, suicides by soldiers like Sergeant Lube tell a troubling story about the toll of war on the nation’s elite troops. For 12 long years, those forces, working mostly in secret, carried the burden of much front-line combat, deploying time and again to the most violent sectors of Iraq and Afghanistan.