The 154 suicides in the first 155 days of the year eclipses the number of US forces killed in action in Afghanistan in the same period.
The numbers have shocked the US military, which had been expecting them to fall after levelling off in 2010 and 2011.
Jackie Garrick, head of the Pentagon’s new Defence Suicide Prevention Office, said: “We are very concerned at this point that we are seeing a high number of suicides at a point in time where we were expecting to see a lower number.”
Officials believe the weak US economy may be playing a part as thousands of American troops head home from Afghanistan.
They say other explanations include combat exposure, post-traumatic stress and the misuse of prescription medications.
Army statistics have revealed that soldiers with multiple combat tours are at greater risk of taking their own lives.
But a substantial proportion of army suicides are committed by soldiers who were never deployed.
Kim Ruocco, whose husband, marine helicopter pilot Major John Ruocco hanged himself in 2005, said he was unable to bring himself to go for help.
She said: “He was so afraid of how people would view him once he went for help.
“He thought that people would think he was weak, that people would think he was just trying to get out of redeploying or trying to get out of service, or that he just couldn’t hack it – when, in reality, he was sick.
“He had suffered injury in combat and he had also suffered from depression and let it go untreated for years. And because of that, he’s dead today.”
Critics say the US military is still not doing enough to recognise the problem.
And last month a senior general retracted a statement in a blog post in which he wrote: “I am personally fed up with soldiers who are choosing to take their own lives so that others can clean up their mess.
“Be an adult, act like an adult, and deal with your real-life problems like the rest of us.”
US military suicide numbers began surging in 2006 and statistics include only active-duty troops, not veterans who returned to civilian life after fighting in Iraq or Afghanistan or non-mobilised national guard or reserve members.
The defence secretary, Leon Panetta has drawn attention to the situation, writing: “We must continue to fight to eliminate the stigma from those with post-traumatic stress and other mental health issues.”
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