Anxiety, post-traumatic stress disorder (PTSD) and depression are much more severe for TPV holders than for PPV holders, mental health professionals from the Sydney-based Service for the Treatment and Rehabilitation of Torture and Trauma Survivors and the University of NSW School of Psychiatry revealed in the latest issue of the Medical Journal of Australia.
In the first study of its kind in Australia, researchers interviewed TPV and PPV holders from similar cultural and language backgrounds who had experienced similar trauma and persecution before seeking refuge.
They found the TPV holders studied had experienced the added stress of being held in immigration detention centres, of having very few of the entitlements of Australian citizens, and of facing an uncertain future.
The cumulative effect meant TPV holders were much more susceptible to mental health problems, said lead author Zachary Steel, a Senior Lecturer in Psychiatry at UNSW.
"TPV holders exceeded PPV holders on all measures of psychiatric disturbance and mental disability," Mr Steel said.
"(Their) TPV status made a substantial contribution, being by far the greatest predictor of PTSD symptoms.
"Adverse prior detention experiences and current living difficulties associated with TPV status each made substantial and independent contributions to PTSD symptoms.
"Our study provides consistent evidence that the migration trajectory experienced by TPV holders, particularly adversity in detention and ongoing living difficulties, is accompanied by persisting and wide-ranging mental health problems and associated disability."
All TPV holders had been in immigration detention centres in Australia and reported their experience of detention had caused serious to very serious stress.
More than 90 per cent reported serious stress in detention associated with being interviewed by immigration officers, not receiving adequate medical treatment, exposure to acts of violence and brutality and seeing people attempt suicide.
Significant numbers said stress was also caused by alleged assaults by officers, being handcuffed during transport, being woken during the night for head counts, being forced to use unhygienic toilets and being placed in solitary confinement.
The proportion of TPV holders experiencing living difficulties since release from detention exceeded that of PPV holders for all items assessed. Over 90 per cent of TPV holders experienced anxiety about possible repatriation.
"Since our research was completed, Australia has revised its immigration policies, substantially limiting mandatory detention and allowing for external review of the grounds for detention after two years," Mr Steel said.
"TPV holders have been allowed to apply for permanent residency under alternative immigration streams.
"Several factors undoubtedly shaped these changes, but concerns about the mental health of detainees proved to be a decisive feature of the debate.
"Nevertheless, the extent to which these reforms address the negative consequences of prolonged detention, insecure residency and harsh visa conditions remains to be demonstrated.
"Health professions must continue to monitor the interplay of policy and mental health outcomes in this and other vulnerable groups."