Five of the miners trapped underground in Chile for months to come are struggling psychologically, officials said Friday, as engineers prepared to start drilling an escape shaft.

While the rest of the 33 trapped miners were happy to take part in a video to show families they were bearing up despite what has so far been a three-week ordeal, the smaller group refused and were exhibiting signs of depression.

"Five of the miners are isolated, are not eating well and do not want to appear on camera," Health Minister Jaime Manalich said. "This is what we call depression."

The minister said a psychiatrist would attempt to treat the men over an intercom system dropped to them.

The mental malaise emerging among the miners holed up in a shelter 700 meters (2,300 feet) under the surface of the earth augured badly for the months of continued captivity the men have yet to endure.