Background
Children and adolescents growing up in child welfare institutions have been frequently exposed to traumatic events and psychosocial stress and show elevated rates of mental disorders. Yet, there is a lack of empirically supported treatments to provide adequate mental health care for children in care sufering from trauma-related mental disorders such as posttraumatic stress disorder (PTSD), depression, and anxiety. The Cognitive Behavioral Intervention for Trauma in Schools (CBITS) is an evaluated trauma-focused cognitive-behavioral group intervention, which has proven to be efective in reducing symptoms of PTSD, depression, and anxiety for traumatized children in group settings. The trial will evaluate the efectiveness of the CBITS intervention as an outreach treatment compared with an enhanced treatment-as-usual condition (TAU+) within the German mental health and child welfare system.

Methods
In a randomized controlled trial (RCT) involving N= 90 children and adolescents, we will compare CBITS with TAU + . Participants between 8 and 16 years, reporting at least one traumatic event and moderate posttraumatic stress symptoms (PTSS), will be randomized within their child welfare institution to either one of the conditions using a CATS-2 severity-stratifed block randomization. Assessments will take place at baseline, as well as 4 months and 10 months after baseline. The primary outcome is the severity of PTSS after 4 months. Secondary outcomes are depression, anxiety, irritability/anger, quality of life, and global functioning level.

Discussion
The results of our trial will provide evidence regarding efective treatment options for traumatized children in care, which represent an understudied population with limited access to mental health care. Additionally, it could serve as a blueprint for implementing trauma-focused outreach group treatments for children in care and increase the accessibility to appropriate treatment.