Defense Department spokesman Col. Steve Warren said Bergdahl, now at a military hospital in Germany, is “conversing with his medical staff and becoming more engaged in his treatment plan. He is resting better and showing signs of improvement.”

For now, Warren said, Bergdahl is “engaging only with his reintegration team” of doctors, psychologists and others. There’s no timetable for returnees like Bergdahl to proceed through readjusting after being in captivity, Warren said, so he and his doctors are going forward at their own pace. Later Thursday, defense officials said the process of acclimating can take months or years.

( Also on POLITICO: Obama: ‘No apologies’ on Bergdahl)

Bergdahl is talking about his experience as a Taliban prisoner for about five years, Warren said, but that may not constitute a formal debriefing for either intelligence purposes or to determine the circumstances under which he went missing in 2009.

“This process is about helping a returnee gain control of his emotions,” Warren said. “One of the methods the psychologists use … is to allow him to tell his story.”

Bergdahl has become a political lightning rod in Washington amid reports that he may have deliberately abandoned his post before he was captured, potentially costing the lives of soldiers who searched for him or continued to operate in Southeast Afghanistan. One of the questions surrounding his return is whether, as he begins to tell his story, he could put himself in legal jeopardy if he confirms other troops’ accounts that he walked away from his base.

( Also on POLITICO: Officials: Threat to Bergdahl’s life led to swap)

A person coming back from captivity is typically offered confidentiality during the “reintegration” process, two defense officials said Thursday. Lawyers are present both to protect the returnee and the team helping him, they said, and the Defense Department teams are trained to stop debriefing if a legal question arises.

The officials, a personnel recovery expert and a psychologist, briefed reporters on the condition they not be identified and that they not refer specifically to Bergdahl’s case. They agreed to talk — in general —about the Pentagon’s policies governing returning prisoners and said the experiences of each returnee is different.

Typically the second phase of reintegration, the one through which Bergdahl is working now, can take from 24 hours to as long as three weeks, the psychologist said. The next phase, in which a person returns to the United States and begins to readjust to home and civilization, has taken as little as 24 hours and as long as five years.

( Also on POLITICO: McCain aide disputes flip-flop charge)

The psychologist said that prisoners held by less organized groups, as opposed to foreign governments, “typically have harsher treatment.” The prisoners held in Vietnam’s infamous “Hanoi Hilton,” for example, typically had “more resources,” comparatively speaking, than those held in jungle prison camps.

Bergdahl is said to have been moved around at least part of the time he was held captive in Afghanistan and Pakistan by his Taliban and Haqqani Network captors.

The psychologist said returnees need to regain some of the basic mental building blocks of modern life. Their captors are typically “bad guys” who took away their ability to act for themselves, plan, predict and trust, so they must learn to do all those things again. Too many steps forward too quickly can be overwhelming.

Publicity — positive or negative — also can affect a returnee “hugely,” the psychologist said. A person’s medical team typically begins showing him press reports about his story during the second phase, and preparing him to respond to press and public questions in the third. A large amount of media interest can make the adjustment process more difficult, the psychologist said.

“The more complicated the media interaction, [the] more complicated the reintegration is. Everybody has a piece of a story, and very few people have the whole story,” the psychologist said. “So if the media focuses on one piece of the story and a person coming back hears that, and then they’re wondering, ‘Why didn’t they wait for the whole story?’ That complicates it.”