Suicides, family breakups, depression and social stigma are just some of the hidden legacies of the Iraq war among the more than one million US troops who have served in the campaign.
While nearly 4,000 American troops have been killed in the war and more than 29,000 have been wounded, those who escape physical injury still stand a high chance of developing psychological scars that may stay with them for life.
Some have watched comrades die or witnessed unspeakable carnage, while others may have found it hard to come to terms with the trauma of killing.
A report last month focused on the psychological toll on troops from the 10th Mountain Division based in New York state, one of the most deployed brigades in the US Army since the September 11 attacks of 2001.
The study, by the group Veterans for America, found that the mental health care provided for soldiers did not meet the psychological burden they had suffered during repeated deployments in Iraq and Afghanistan.
"Sooner or later, and likely sooner, we're going to hit the wall and something will have to change," said Bobby Muller, the founder of Veterans for America and a former Marine paralyzed while serving in Vietnam in 1969.
The report criticized a Pentagon policy of extending tours of duty from 12 to 15 months and insufficient time between deployments to recuperate as key factors in the high level of mental problems among returning US troops.
On its most recent deployment, the 10th Mountain Division's second brigade combat team lost 52 troops killed in action, while a further 270 were wounded, out of a total troop strength of around 3,500 soldiers.
The figures reveal the unit's soldiers to be five times more likely to be killed in action than the average soldier serving in Iraq or Afghanistan, according to the report -- a major psychological stress on the troops.
The study found troops in the unit reported low morale, spousal abuse and attempted suicides. And yet, troops had to wait up to two months for an appointment with a mental health expert once they returned, it said.
A separate report by the Army released earlier this month found that soldiers on their third or fourth combat deployment were at particular risk of suffering mental health problems.
Major General Gale Pollock, the Army's deputy surgeon general, said the results simply "show the effects of a long war."
A similar report by the Army's Mental Health Advisory Team released in 2007 found that 28 percent of soldiers who had been in high-intensity combat were experiencing post-traumatic stress disorder, or acute stress.
It also found that the percentage of soldiers with severe stress, emotional, alcohol or family problems had risen more than 85 percent since the invasion of Iraq five years ago.
In January, the Army said suicide rates had soared over the past three years, attributing the rise to strains on family relationships.
"I think it's a marker of the stress on the force," said Colonel Elspeth Ritchie, psychiatric consultant to the army's surgeon general.
According to the figures, more than 2,000 soldiers tried to take their own lives or injure themselves in 2006, compared to about 375 in 2002.
Yet another study by the Defense Department in June last year found that more than one third of active Army personnel who returned from combat experienced some degree of mental health problems.
However, according to some campaigners, the numbers could under-state the true scale of psychological problems, given that some troops are reluctant to admit to trauma, for fear of being stigmatized or overlooked for promotion.
Veterans for America said it considered that military commanders also wielded too much influence in the treatment of psychological problems.
In response to that report, the military at Fort Drum, the home of the 10th Mountain Division, acknowledged some shortcomings while characterizing elements of the study as misrepresenting the true picture.
"While we've made great strides this year to increase our mental health provider capacity, we acknowledge the shortage of mental health providers, not just here but across America," unit commander Major General Michael Oates said.
"We welcome the opinions of outside interest groups, but we're more interested in well-researched solutions to these problems," spokesman Lieutenant Colonel Paul Swiergosz added in a statement.