Alexandra Chen was a trauma specialist working in Lebanon and Jordan when she noticed that a specific group of kids were struggling in schools.

Chen kept getting referrals for refugee students who had fled the war in Syria. They were having trouble focusing and finishing schoolwork. Some had even dropped out of school.

She wondered to what extent the different stressors they faced — exposure to violence in Syria, lack of resources or concerns for the future — affected how they navigate their daily lives. Specifically, she wondered, which had a bigger impact: past trauma or the poverty they now lived in?

Experts she wrote to said they didn't know and advised her to investigate the question herself. Chen, who's now getting her Ph.D. at Harvard, worked with a team to devise a study that aimed to untangle the threads of poverty, trauma and other adversities. They studied 240 teen Syrian refugees, comparing them with a group of 210 Jordanian youth who were also considered at-risk but didn't have a background of war.

The researchers gave the teenagers surveys to gauge trauma and insecurity. To determine poverty, they asked the teens whether their families had items such as bedframes, cars, TVs, smartphones, refrigerators and water heaters.

Then the teens played "games" on a tablet, which were designed to measure working memory and inhibitory control — their ability to recall what they had just seen and to filter out irrelevant information when pursuing goals. These are two of several critical components that make up a person's executive function — how their brains process information and make decisions. Executive function is considered vital for focusing and completing daily tasks, like schoolwork or the multiple jobs these kids had.

The researchers' results are published in a new paper in Child Development. While the study documents high exposures to violence, symptoms of PTSD and anxiety about the future among the teens, it finds that the constant stress of being poor seems to most interrupt the way their minds work.

"It's the struggle of having to survive, perhaps not having enough to eat; the stress of supporting the family in various ways — begging, selling things, working odd jobs and ridiculous hours to support their families," says Chen.

The researchers found that more than half of the Syrian teen refugees had symptoms of PTSD and were poorer and had gone to school for fewer years than their Jordanian counterparts. The researchers also found correlations between poverty, less schooling and poor working memory. The refugees' abilities to remember things they just saw were, by the researchers' measure, more appropriate to younger children.

They also found that girls did worse across the board, in both working memory and inhibitory control. Chen says it probably indicates gender differences in opportunities and social roles.

"It's quite common for boys to have more access to schooling in some rural areas of Syria," where many refugees come from, she says. And while girls often take care of housework and siblings, boys are often out in the streets bartering, negotiating and navigating their own safety — tasks which may frequently work their brains in new ways. "It's context more than anything," Chen says.

"There are few good studies in these areas because it is so difficult to conduct good research in war-torn parts of the world," says Mina Fazel, an Oxford psychiatry professor not affiliated with the study, who works with refugees in the U.K.

The study was also limited to a population which was, on average, three years removed from war. Chen says more recent trauma might have stronger impacts on how the mind works. And beyond measuring working memory and inhibitory control, the study doesn't comment on how past trauma may affect other ways the mind works.

Previous studies in the U.S. have suggested that poverty, more than violence, predicts worse cognitive performance. "This is not just about refugees," says study co-author Kristin Hadfield, at the Queen Mary University of London. "This suggests that there's a more universal process. We need to be thinking about the impacts of poverty on kids ability to thrive and to think clearly because those are critical for all their lives."

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