Correction: An earlier version of this article incorrectly characterized two aspects of the personal history of Robert Park, a Christian missionary and human rights activist. First, as a teenager antagonistic to Christianity, Park did not “almost always” remain in his bedroom. Second, while his release in 2010 from 43 days of captivity in North Korea brought Park into contact with Rita Vasquez, a communications adviser, she was not “one of his closest friends.’’ Post editors first learned of Park’s concerns on Jan. 24, 2014. The article has been updated.

SEOUL — One year after being released from North Korea, Robert Park still cannot pull his mind away from the country where he spent 43 days.

A Christian missionary from Tucson, Park now lives in Seoul, where he’s trying to establish himself as a human rights activist. But Park is also trying to recover his mental health, something he says he lost in North Korea.

Unlike before his detention, Park stutters. He prays almost compulsively. He has tried to commit suicide several times. And he hasn’t had a haircut since his release, in part because he now feels uncomfortable whenever strangers touch him.

On Christmas Day 2009, Park, hoping to raise attention to Pyongyang’s human rights abuses, entered North Korea - an act Park’s friends liken to a monk setting himself on fire.

“It was just an incredibly pure act that stemmed from a frustration - the inability to get people to care about the worst humanitarian crisis in the world,” said Suzanne Scholte, a well-known activist who heads the North Korea Freedom Coalition.

Though reluctant to speak in detail about his imprisonment, Park says he was tortured and sexually abused by his captors. He calls his treatment “humiliating” and “worse than death.” Scholte suspects that Park was administered a brain-scrambling cocktail of drugs that has left him paranoid, sometimes angry. On bad days, Park believes his life is in danger. He says North Korean agents will kill him for speaking so harshly about their government.

Park says his parents wish he would worry for the moment about his own health, not the health of 23 million people. But Park won’t listen. That’s why he pulled himself out of a psychiatric hospital in Tucson and returned in September to Seoul, where he had been living before entering North Korea. That’s why he speaks at as many churches as possible, presenting slide shows that feature photos of children, little more than limbs and rib cages, and illustrations of firing squads. Park calls this “genocide.” He criticizes Washington and Seoul for viewing North Korea, foremost, as a nuclear-armed security threat while ignoring the way North Korea treats its own citizens.

On his best days, Park speaks so clearly about North Korean issues, his friends suggest he’ll one day be able to testify before Congress. He has narrowed the focus into one purpose, saying, “Honestly this is my only reason to live - to support the North Korean people.”

‘He is wounded’

When Park entered North Korea, he assumed tremendous risks - and he ignored the advice of many friends and experts, who warned him he could be shot on sight.

Previous Americans detained in North Korea had turned into diplomatic pawns, used by Kim Jong Il to leverage high-profile rescue visits from Bill Clinton and then-Rep. Bill Richardson. But days before he crossed the border, Park told Reuters, “I don’t want President Obama to come and pay to get me out.”

Park walked across the frozen Tumen River, the border between China and North Korea, on Dec. 25, 2009. He wore no coat. He yelled, while approaching North Korea, “South Korea and America love you.” He smashed a photo of Kim Jong Il. And then, on the shores of a North Korean village not far from a political prison camp, he was arrested.

Park says he was held in three separate places. His worst treatment came at the first. But later, Park said, he sometimes was treated by doctors who “tried to make me look as good as possible.” When pressed gently for further details about his detention, Park panics and strains to change the subject. One Seoul-based humanitarian organization interviewed 100 prison camp torture victims, who reported caning, electric torture and the kicking of genitals. Many, in months and years after, suffered from insomnia, nervous breakdowns and social phobias.

Before North Korea released Park, officials fitted him for a new, black suit, which he wore on his flight to Beijing.

“He is wounded, of course,” an acquaintance, Rita Vasquez, said. “He has PTSD real bad right now. The anxieties. The fears. His stuttering. When he talks on the phone, he jumps from subject to subject, back and forth. And can’t make up his mind.”

Breaking down barriers

A combination of frustration and faith drove Park into North Korea.

He had faith, because already religion had given him so much. Park had been a troubled teen, writing words like “hate” and “kill” on his arms. He found warmth, for the first time, when he read the Bible.

Soon after, he sold his favorite Beethoven records and poetry books and donated his Volvo to the Salvation Army. He took a volunteer job at a home for abused children.

“The barriers between me and other people started to get broken,” Park said, and for the next eight years - until Christmas Day 2009 - many who encountered Park described his generosity, his willingness to help others.

But Park also felt frustration as he adopted North Korea, where his grandparents had lived, as his pet cause. Park would hold rallies for North Korean human rights causes, hoping thousands would show up. Often only hundreds did. He also befriended numerous North Korean refugees, and he realized prayer alone couldn’t help their pain.

“And I remember telling them how to pray - like it’s that simple,” Park said. “And that’s when I started to have this urgency. I’d be up at 3 a.m. and they’d be drinking because of the pain. Or they’d try to pray and they couldn’t even say the words because of the sobbing.”

Park says now, looking back on his decision to cross into North Korea: “I don’t want others to do this. I just hoped that this could galvanize people to action. Because this is a society that needs change now.”

Special correspondent Yoonjung Seo contributed to this report.