Chile's trapped miners have set survival records for enduring more than two months in the depths of a collapsed mine, but even as they are close to being rescued the psychological toll of the ordeal is far from over.
Rescuers hope to pull all the miners to safety in a complex operation over the next two days but concerns over their physical well-being are already giving way to fears of battered psyches.
The next serious test will be the rescue mission itself, a harrowing passage more than 620 metres (2,000 feet) to the surface in a claustrophobic capsule.
"That's going to be a hairy ride. It may end up being the most traumatic part of the entire experience," said Robert Hogan, a psychologist who has worked with the U.S. Navy to develop personality tests for people in isolated environments. Marcela Zuniga, a paramedic who has spoken with the men trapped inside the gold and copper mine in Chile's Atacama desert, said anxiety levels have risen as the final stage of the rescue operation approaches.
"They told me they were calm but ... you could see in the conversations that the group was more uneasy in general. And how do you handle that anxiety?"
The men were stranded deep inside the mine when it caved in on August 5 and for the first 17 days they were believed dead.
When contact was finally made, rescuers warned it would take months to reach them, but the operation has moved more rapidly than initially feared and the government has kept the miners in contact with their family members and psychiatrists.
Letters are sent up and down in narrow plastic tubes and experts have kept the miners busy by arranging phone calls, sending down videos, and putting them on an exercise regime. The men have also done their best to maintain a sense of order, designating a leader and a spiritual counsellor, organizing into shifts and dividing their tunnel into spaces for meals, recreation, rest and hygiene.
When they are finally pulled out, the miners will spend two days under observation in hospital, and Health Minister Jaime Manalich has promised continued counselling for at least six months.
While many of the miners have shown resilience, experts say some of them are likely to develop the classic symptoms of post-traumatic stress disorder in the months to come.
"Some will have nightmares, recurring flashbacks, night sweats, free-floating anxiety and so forth," said Hogan.
"The big trauma here was lack of control -- no control and no predictability ... That's how you make people crazy." Experts say family frictions are common after deeply stressful events, and that the miners and their close relatives will have to manage their expectations after looking forward for so long to being reunited.
In some cases, the mental toll has already shown. When rescuers first established contact with the miners, Manalich reported that some of them were at "greater emotional risk," showing signs of withdrawal and irregular diets.
He said the government is considering mental health in drafting a list of the more fragile miners to be brought to the surface as soon as possible, once more able-bodied miners have confirmed the safety of the ascent.
John Fairbank, a Duke University psychiatry professor, said it will be important to continue screening the miners for signs of psychological trauma long after the initial joy of rescue. And given the record length of the miners' confinement, psychiatrists can't be certain how soon symptoms will set in or how long it will take the men to overcome the ordeal.
"These miners have a lot to teach us about resilience and recovery," said Fairbank.