NAURU – A psychiatrist has said an acutely unwell child held within Australia’s offshore detention regime should not be returned to Nauru because his long-running detention there is causing his mental illness.

The 17-year-old boy, referred to as Hamid, is currently on the island of Taiwan, where he was taken, along with his mother, for health treatment.

His mother, Fatemeh, was flown from Nauru after a delay of 18 months, for a heart operation. She has been treated on Taiwan.

Hamid, who had been held on Nauru since he was 11, was suffering from acute and worsening depression on the island. Since being taken to Taiwan with his mother he has had a number of meetings with a psychiatrist at the Taiwan Adventist hospital.

The psychiatrist has said he should not be sent back to Nauru.

“The depressive symptoms were not improved, moreover, he had persistent suicide ideation and some organised plans,” the latest psychiatrist’s report says. “I have already prescribed antidepressant for him and told his mother, who is also a patient with major depression, to accompany him.

“After discussing with the patient, his mother and their case manager, I think the environment in Nauru is not only not unhelpful with his depression, but even the trigger of his depression.”

The doctor’s finding – that the fact of being held on Nauru indefinitely is contributing to, and even causing, Hamid’s mental distress – has caused significant consternation within the Australian Border Force and Department of Home Affairs.

Taiwan was chosen by Australia as a suitable third country to which people held on Nauru could be sent for medical treatment largely because it was outside the protections of the refugee convention and the reach of Australia’s courts, while still providing high-level care.

Most asylum seekers and refugees brought to Australia for health treatment win court injunctions preventing their return to offshore processing centres in Nauru or Papua New Guinea.

But the mental health of children still held on Nauru – most have been there five years – has reached “crisis levels”, sources on the island say.

Lawyers have been forced to take individual cases to court in order to have children moved.

Three pre-teenaged children, suffering acute mental illnesses and having made repeated suicide attempts, have been urgently brought to Australia but only after court action was launched in Australia to have them moved.

In two of the three cases, the Australian government opposed the children’s transfer in court. The government lost both, and acquiesced to the third transfer.

Nauru sources say there is growing criticality of child mental health issues, with some influenced by the condition and actions of others.

“It’s an epidemic – the risk is so serious,” a source from the island told Guardian Australia.

About 142 refugee and asylum seeker children are held on the island.

Psychological reports, prepared over months, and for different children, have argued that the fact of incarceration on Nauru – many children still live in tents inside the “open” regional processing centre and do not attend school – is causing severe depression that cannot be effectively treated on the island.

The Australian government’s health contractor IHMS has conceded in court there is no child psychiatrist permanently based on Nauru, and that the standard of care is inadequate.

Child psychiatrist reports provided to Guardian Australia have charted the decline of Hamid’s mental health on Nauru.

The reports say he was initially achieving well at school but began to deteriorate after several years in detention and has declined precipitously in recent months.

He has, reports say, a “profound sense of hopelessness” and “a high level of suicidal ideation”.

Over the course of his time on Nauru, Hamid has received mental health treatment of poor quality, with reports copied from earlier information, and recommendations for specialist treatment not followed up.

Several psychiatrists have warned Hamid’s condition would deteriorate without intervention.

“I would predict that he would continue to deteriorate in terms of his mental state and function. It is highly likely that he will become more acutely suicidal.

“He is a young man who is extremely hopeless and despairing – these aspects highly increase his risk of harm to himself and should not be underestimated. Even if he does not end his life then it is likely that he will endure many of these symptoms for a long time if he does not receive the appropriate treatment.”

Fatemeh fled Iran in 2013 following a violent family breakdown that forced her to abandon her job and possessions, and leave the country with her son.

The uncertainty over their futures has destroyed her and her son’s mental health, Fatemeh told Guardian Australia.

“I have been officially accepted as a refugee, but still live in a tent. If I was a imprisoned as a criminal in a third-world country, that government would provide me with basic facilities.

“My son says to me, ‘let’s attempt suicide together’. He believes the only way to freedom is in death. I have sympathy for all the mothers and their children who live in Nauru. We are preyed upon and our lives are subjected to cruelty.”

Hamid and his mother were flown to Taiwan on March 9. Fatemeh has received treatment for her heart condition. It is unclear whether and when they will be returning to Nauru.

Guardian Australia has approached the Department of Home Affairs for comment on the family’s case but has not received a response.

- Guardian