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The executive order that President Trump signed this week ended the practice of separating migrant children from their parents, but no one knows yet how the children and parents already separated will be reunited. Psychologists say that those children already in government facilities, even for just a short time away from their parents, can suffer lasting damage. NPR's Rhitu Chatterjee reports.
RHITU CHATTERJEE, BYLINE: The children who've been split up from their parents are facing one of the biggest stresses of their lives. Megan Gunnar is a developmental psychologist at the University of Minnesota.
MEGAN GUNNAR: Of all of the kinds of things that can happen to a young child, loss of that parent is the biggest kind of trauma.
CHATTERJEE: She says that trauma can pave the way for a range of mental illnesses later in life.
GUNNAR: Post-traumatic stress disorder, problems with attention, a lower threshold for perceiving things as dangerous, constant vigilance against bad things happening to them again, a shattering of their sense of safety in the world.
CHATTERJEE: The U.S. detention centers are also set up in a way that can adversely affect kids. Charles Nelson is a developmental neuroscientist at Harvard University. And since 2000, he's been studying children growing up in orphanages in Romania.
CHARLES NELSON: There is a very eerie similarity to what I'm seeing in these detention centers or these tender care centers and what we see in Romania.
CHATTERJEE: For one, he says, there's a large number of children.
NELSON: With very little in the way of caregiver support.
CHATTERJEE: And that, he says, also affects their development.
NELSON: Not having consistent and sensitive caregiving can lead children down a road that leads to compromised mental development, psychological development, cognitive development, biological development.
CHATTERJEE: Nelson has studied the Romanian kids as they've grown up. He says the orphans' brains look different. They have lower IQs. Now, most of the remaining children spent years living this way. But other research shows that even short separation can have a lasting impact. Luis Zayas is a psychologist and the dean of the School of Social Work at the University of Texas at Austin.
LUIS ZAYAS: Even a few days or a couple of weeks of detention, particularly separated from a parent in the way that it was done, can cause long-term damage.
CHATTERJEE: He has worked with immigrant children and families for many years.
ZAYAS: With that damage, those children will enter life ill-equipped to really deal with the stresses of their future lives.
CHATTERJEE: He says the damage of separation can be reduced if the children are quickly reunited with their parents. The government says it's working on reunification, but it's still unclear how long this will take. Rhitu Chatterjee, NPR News. Transcript provided by NPR, Copyright NPR.