Just months after Dr Ahmad Al Ajlan begun a new job as a university lecturer in the Syrian city of Deir ez-Zor, he was forced to flee his country for Europe. When he arrived in Germany in March 2015, after several months of travelling, he was placed in a number of camps before being allocated a cramped apartment with five other refugees.

They are fleeing war, famine and persecution, risking treacherous journeys across deserts and seas in search of safety. But helping refugees and asylum seekers to cope with the psychological scars caused by their experiences could help them adjust to life in their new homes.

For a teenage refugee starting a new life in Europe, going to school and using digital media form a big part of navigating an unfamiliar society. But appropriate interventions at school and online could help them feel more at home in a new country.

In the last few years, the integration of refugees into European societies has become an urgent issue.  Since 2015, nearly 4 million people have applied for asylum in the EU and many are now beginning to make new lives here. What does it mean to become integrated into a new society? How can it be achieved? And are current policies helping or hindering? We spoke to Dr Dominik Hangartner from the Immigration Policy Lab at ETH Zurich, Switzerland, about what the evidence tells us about successful integration. Here are five takeaways.