With their high walls, barbed wire, segregated units and guards, many asylum seekers would agree that immigration detention centres are prisons in all but name.
Many aspects of daily life are subject to rigid rules. There's often nothing to do but wait. Robbed of the ability to take control of their lives, detention can have a serious impact on asylum seekers' mental health, experts say in the latest edition of Forced Migration Review.
"Detention increases anxiety, fear and frustration and can exacerbate previous traumatic experiences that asylum seekers and migrants endured in their country of origin, during the trip or during their stay in a transit country," Medecins Sans Frontieres (MSF) said in a chapter entitled "Health at risk in immigration detention facilities".
"Their vulnerability is further aggravated by uncertainty about their future, the uncertain duration of their detention and the ever-present threat of deportation."
The medical charity said tough living conditions, overcrowding, constant noise, a lack of activities and having to depend on other people's decisions all contributed to feelings of defeat and hopelessness.
Detention was the precipitating factor for the mental health complaints of 37 percent of patients seen by MSF staff in Greek immigration detention centres in 2009-2010, it said.
Writing about Canada, psychologist and researcher Janet Cleveland shared findings of a study she had done comparing the impact of imprisonment on the mental health of 122 asylum seekers held in detention centres with the experience of 66 asylum seekers who were not detained.
After a relatively short detention – on average about a month – 32 percent of detained asylum seekers reported "clinically significant" levels of post-traumatic stress symptoms compared with 18 percent of the migrants who had not been locked up. Depression levels were 50 percent higher among detained asylum seekers than their counterparts who were not detained, Cleveland said.
In her chapter, Alice Farmer, Human Rights Watch researcher, looked at what detention was like for children.
"Children may be arbitrarily detained, held in cells with unrelated adults and subjected to brutal treatment by police, guards and other authorities," she said, adding that children are often held in conditions that fall far short of international standards.
Greece – one of the major gateways for asylum seekers entering the European Union (EU) – was identified as a country with a particularly poor record of treating child migrants.
Children who were not accompanied by any adults can spend months in detention centres, often sharing a cell with strangers.
Once released from detention in Greece, unaccompanied migrant children are typically served an order to leave the country. If they do not leave, Farmer said, they could find themselves back in detention. One 10-year-old Somali girl who was alone in Greece was detained four times in six weeks.
Not only are children often exposed to violence or exploitation in detention centres around the world, they are also deprived of an education – sometimes for years, Farmer said.
So, what are the alternatives?
Decent housing in the community and a range of social services including legal aid must be part of the solution, Philip Amaral of Jesuit Refugee Service Europe said. Drawing on the lessons of a pilot project in Belgium, Liesbeth Schockaert highlighted the successes of a scheme to test open family units, a set up of individual houses and apartments that gave families seeking asylum a semblance of normality.
Such initiatives would, at least, be a start.