NAURU — Shaped like a peanut and smaller than some big-city airports, this tropical Pacific island has an unusual history. Thanks to rich deposits of a fertilizer ingredient, Nauru's 11,000 citizens were once among the wealthiest people on earth. But after much of the phosphate was plundered, Nauru squandered its wealth on bad investments, like a 1993 musical about Leonardo da Vinci.

That left the island searching for new sources of income, and in recent years it found an answer by becoming a holding station for hundreds of refugees who tried to reach Australia by boat. Australia designed a policy of keeping boat refugees and asylum seekers far from its shores to deter more of them from trying to make the voyage, but many critics say the policy violates human rights.

The fate of those refugees, including a growing number of children who advocates say are suffering from life-threatening medical conditions, is casting a shadow over the Pacific Islands Forum conference that starts in Nauru on Monday night. The forum brings together 18 members including Australia and New Zealand to discuss regional issues.

On the agenda are plans for an enhanced regional security agreement and discussions on the threat that climate change poses for low-lying islands. China's growing role in the Pacific will likely be a point of tension, with some forum members favoring diplomatic relations with Taiwan. But Nauru has been eager to limit discussion of the refugees.

For years, Nauru has effectively prevented most journalists from reporting firsthand by charging 8,000 Australian dollars ($5,750) to apply for a media visa. Nauru has waived the fee for the forum, but has allowed only a handful of journalists and placed restrictions on them.

Many of the more than 600 refugees on the island describe the hopelessness and depression they feel after being stuck in limbo for up to five years. They say they're not accepted by the locals, and that many of their children don't attend island schools because they are bullied or made to feel unwelcome.

While the U.S. has taken some of the refugees from Nauru under a deal struck by former President Barack Obama and reluctantly accepted by President Donald Trump, many refugees fleeing places like Iran and Somalia say they have no realistic hope of being allowed into the U.S. under its current immigration policies, which has sharpened their sense of despair.

A series of Australian court cases have described how some of the 120 or so refugee children on Nauru have been evacuated because they are suffering from resignation syndrome, a medical condition in which they withdraw socially and stop eating and drinking.

Ahead of the forum, Nauru has hit back at the findings.

"Sadly some refugee children on Nauru are being manipulated into self-harm by some of their families (supported by activists) in a disgusting & tragic political game," the government wrote on Twitter. "The end goal is to make international headlines & get to Australia. This is the real child abuse."

But Louise Newman, a professor of psychiatry at the University of Melbourne who has advocated for the refugee children, says some of their symptoms are impossible to fake.

"To all intents and purposes, they become comatose," she said. "It's like they go into hibernation from the overwhelming stress. Their brain switches off engagement with their social environment. They don't respond to pain. Their knee-jerk reflex is absent."

Newman said she has seen four cases of Nauru children aged between about 10 and 14 with resignation syndrome. She said they typically need to be rehydrated intravenously and that full recovery can take a year or more.

"It's very confronting," she said. "It speaks to me of the terrible consequences of policies that are poorly thought through for children. Australia should not be condoning what amounts to a form of state-sponsored child abuse."

Nauru in recent weeks has dismantled a much-criticized tent encampment that was home to some of the refugee families and relocated them into community housing. On Twitter, Nauru's government has denounced media reports that it was trying to polish its image ahead of the forum as "#FakeNews."

"Fact - it's dismantled because no longer needed," the government wrote.

Many of the leaders gathering this week in Nauru have little appetite for intervening in what they see as an issue between Nauru and Australia.

"We've got 50,000 people who are homeless back home," said New Zealand's Foreign Affairs Minister Winston Peters in Nauru, adding "we have to help fix their lives up as well before we start taking on new obligations of the level that some people would like."

Aside from the refugee issue, Australia faces other challenges at the forum, said Jonathan Pryke, the director of the Pacific islands program at Australia's Lowy Institute, a think tank.

A draft declaration for an enhanced security agreement states that climate change is the biggest risk to the region, Pryke said, yet climate change has become such a toxic issue in Australian politics that it helped topple former Prime Minister Malcolm Turnbull last month.

Turnbull's replacement Scott Morrison is planning to skip the forum, which Pryke said is not a good look, and he will instead send new foreign minister Marise Payne.

"I imagine they'll have to hold their nose to sign off on the declaration," Pryke said of the Australian delegation.

He said that as a tiny island, Nauru, which has been independent for 50 years, has limited options for making money. Despite that, Pryke said, it has managed to confound pessimists by surviving several boom-and-bust periods and the sometimes extravagant lifestyles of its political elite.

After losing the money from the phosphate, Pryke said, Nauru, which is just 21 square kilometers (8 square miles), remade itself first as a tax haven and money laundering hub and later as the camp for Australia's refugees.

"They have been a bit of a chameleon when it comes to generating new revenue," he said. "It's a good income source for them now. But it does come at the cost of the wellbeing for individuals who are on the island against their will. It's hard to justify."