For over a decade, Australia has used offshore detention to discourage asylum seekers arriving by boat, pairing this with onshore detention for those without visas on the mainland. But these policies come at a high cost to the mental health of former detainees.
New research from the University of New South Wales sheds light on the toll, showing high rates of PTSD, depression, and suicidal thoughts among those who were detained, especially offshore. The findings are especially relevant now as other countries consider similar detention strategies.
Unfair detention
The study surveyed 990 refugees and asylum seekers in Australia from 2011 to 2018, including 215 people who had been detained before their release. This data—one of the largest collections globally on the mental health of former detainees—shows that detention sharply raises the risk of severe mental illness. Offshore detainees were up to 20 times more likely to report PTSD and nearly five times more likely to report depression than those detained onshore for shorter periods.
The impact is clearest in prolonged offshore detention, which has affected over 4,000 people on Nauru and Manus Island since 2012. While most were recently transferred back to the mainland, Australia resumed transfers to Nauru in September 2023, leaving roughly 100 people still offshore.
These findings also serve as a warning for countries like Italy and Albania, which ratified an offshore detention deal in February 2024, and the UK, which continues to consider relocating asylum seekers to Rwanda. Denmark, too, has discussed outsourcing asylum processing.
Australia’s offshore detention policy is also incredibly expensive. Detaining a person offshore costs A$22 million per year, while managing them in the community costs just A$3,962. And despite these high costs, the evidence shows that such measures don’t deter people from seeking asylum.
These findings suggest that humane alternatives, like timely onshore processing and regional resettlement partnerships, could be both effective and economical. For countries considering offshore detention, Australia’s experience highlights the need to rethink policies that lead to such high human costs.
