Thousands of teenagers in Syria have witnessed war and death first-hand, but even trying to stay alive can leave lasting damage to their mental health.
BBC Arabic went to Beirut to meet Mohamed, who briefly followed so-called Islamic State. His name, face and voice have been changed for his safety.
Produced by: Joelle Naayem, Eloise Dicker, Dina Demrdash
Illustrations: Jonathan Blezard