The bottom of the pit

His paranoid delusions were not so outlandish when local history was taken into account. In February 2011, Islanders, Aboriginal and African youth rioted in Mt Druitt. Ofato says he was not involved.

But Ofato says he was once associated with a bikie group, where he worked as a standover man. He describes his role, rather euphemistically, as an assistant debt collector. He felt proud when other gang members admired his physicality and the warrior heritage of his ancestors. 'They kept going on about how I could scare the shit of people without having to do anything.' he says, a little bemused.

He refuses to elaborate, but says he never needed to get violent. He left the gang because he didn't want to carry guns.

Ofato still attended church with his family, another Samoan Pentecostal group in Granville, also in Sydney's west. He says he went to please his family, but spent the rest of the week with friends playing football, listening to music and window shopping at the nearby mall. When pressed about why he tried to rob a convenience store, he says his band of merry Samoan brothers, who referred to themselves as Islanders in Da House, wanted to 'show the Lebs' – a local bikie group. He also says his parents were threatening to send him back to Samoa for a year, punishment for his past truancy at school and lack of direction.

Unlike Ofata, I assessed Eli several times after our first encounter. I considered prescribing an anti-depressant to help lift his mood, but he resisted the idea, having heard from others that 'happy pills', as he calls them, turned people into vegetables.

I organised a family meeting, a psychiatrist's way of attempting to intervene in social systems associated with the patient's milieu. Two of his siblings attended with his mother, aunt and grandmother. They all lived together in a three-bedroom townhouse, which they rented for $250 a week, cheap for Sydney. His father and uncle were absent – his father working in a country town, his uncle had returned to Samoa. The family had been in Australia for close to a decade, and in New Zealand two decades before that. His grandmother spoke in broken English of an idyllic life on the islands with plentiful food and strong families, but lamented the current poverty there.

Eli was embarrassed that his family was involved, he worried it would affect their health. His mother and aunt had both been diagnosed with diabetes and were on the verge of requiring insulin injections if their sugar levels did not stabilise. Samoa and five other Pacific Islands are among the top ten fattest countries in the world, according to a list compiled by the British Medical Journal in 2012. In spite of his anxiety, Eli jokes that the Samoa airport was full of relatives transporting buckets of Kentucky Fried Chicken from American Samoa.

My treatment focused on providing the family some insight into Eli's mental state and how it might relate to family dynamics. I describe how strong clan expectations and hierarchies could make it difficult for young men to communicate distress or disenchantment. Improving the mental health of patients from 'collective cultures' depended on building greater autonomy for the sufferers. Unfortunately, I did not see Eli again after the family meeting, despite an apparently optimistic encounter.

Mental health nurse and academic from Auckland's Massey University, Dr Sione Vaka, says my experience is far from unique; most Islander patients disappear from treatment early. 'It is a collective culture that simply does not see their distress through the lens of mental health, although this can change with latter generations,' says Dr Vaka, who is of Tongan descent.

When I describe Ofato and his legal predicament, Dr Vaka says the two patients have much in common, despite their differing presentations. 'Youth gangs are often a way of expressing their cultural identity. They are not always able to make autonomous decisions within the expectations of their clan structure.'

There is no direct translation in Tongan for the English word depression, but Dr Vaka says that a growing proportion of patients from the Cook Islands and Tonga ask if their children have ADHD. 'If Islanders develop emotional symptoms it is more likely to be seen as punishment for rebelling against clan expectations or having an overlap with evil spirits.' Tongan elders usually interpret mental illness as being overtaken by spooks, an experience called avanga .

Wellington-based psychiatrist and social researcher Dr Siale Folaiki, whose family is from the Cook Islands, sees the community's problems beginning several decades ago and rooted in socio-economics. 'If the first generation do not get economic foothold, it is the latter generations that start showing up in markers of disadvantage, particularly in the third generation.'