The retired general said the news last week of three suicides of Canadian soldiers, coupled with the coming 20th anniversary of the Rwanda genocide, have left him unable to sleep, even with medication.
"Every day I am reliving the 20th anniversary and reviewing that period of command," he said in an apology to the Senate.
He says he didn't realize how tired he was.
"I simply ran out of steam and fell asleep and crashed my car," he said.
"I am very thankful that nobody was injured or worse by my not being more attentive to the level of fatigue that I have been experiencing."
Dallaire commanded the ill-fated United Nations peacekeeping mission in Rwanda in central Africa in 1993-94.
He was an up-and-coming artillery general when he was tabbed to lead a UN force to oversee a shaky truce in the troubled country.
It seemed a natural assignment. He was a French-speaking soldier going to an area of Africa where French was the second language. Canada carried no colonial baggage to inflame local sensitivities.
But the world collapsed on Dallaire and his small force within months of their arrival. The UN ignored his warnings of coming strife.
After it broke out, major international players rebuffed his pleas for more soldiers, leaving him standing as a helpless observer to genocide.
Dallaire came home to medals and promotion, but his spirit was broken and he spiralled into depression and alcohol. At one point he was found passed out in a public park.
His health suffered. He lost weight. His haunted eyes sank into his haggard face. He left the military.
But a decade later, after much psychological help, support from his wife and children and a book into which he poured his tormented soul, Dallaire bounced back.
Shake Hands With the Devil, his pain-filled, graphic memoir of the genocide won the Governor General's Award for non-fiction in 2004.
He was named to the Senate by Paul Martin in 2005 and has made the cause of child soldiers his own.
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