We investigate the mental health including grief and prolonged grief in children and adult who have lost a family member or other close person. It includes different project, including one project on bereaved children which evaluates a mobile app for bereaved teenagers, including interviewing the participants about their experience of using the app and about their grief. Another project is interviewing children and their parents about the child's grief reactions. A third project is evaluating a treatment for prolonged grief in a RCT.