Post-traumatic Stress Disorder (PTSD) in children and adolescents is often associated with a myriad of significant impairments in daily functioning, including family relationships, school/work, leisure time activities, and social relationships. While a majority of attention has been placed on definition and assessment of post-traumatic stress symptoms (PTSS), less emphasis has been placed on the effect of PTSS on related functional impairment in daily life. The current assessment of PTSD-related functional impairment is conducted either with additional items inserted in PTSD measures that inquire about daily functioning or with the utilization of global functional impairment measures. The former approach is usually based on face validity only and varies content-wise. The latter approach often consists of scales that conflate symptoms with functioning, focus on impairment due to physical rather than mental health problems, and are not validated in trauma-exposed children and adolescents. Furthermore, scales usually do not include sufficient age-specific adjustments for younger children. Thus, the current assessment of PTSD-related functional impairment in children and adolescents demonstrates noteworthy shortcomings. Despite the well-recognized debilitating effect of PTSD on daily functioning, no measure has yet been developed to assess PTSD-related functional impairment tailored to trauma-exposed children and adolescents based on the input from the target population and their caregivers. The aim of this project is therefore to develop an instrument that assesses PTSD-related functional impairment in trauma-exposed children and adolescents (young children age 1-6 years (caregiver-report) as well as for older children and adolescents age 7-18 years (self- and caregiver-report)) by conducting focus groups and a Delphi survey.

Inclusion Criteria:

The same inclusion criteria apply for the focus group discussions and for the Delphi process.

For children and adolescents:

• Children and adolescents, who experienced at least one PTE according to the DSM-5 definition of a traumatic event.
• The PTE(s) must have occurred after the fourth birthday.
• The PTE(s) must have occurred at least 1 month ago.
• Children and adolescents must be 7-18 years of age.
• Children and adolescents are either in trauma-focused treatment at the time of recruitment or they present with at least a moderate PTSS severity according to the Child and Adolescents Trauma Screen 2 (CATS-2) Self-report.
• Children and adolescents must have sufficient command of the German language, excluding a small group of 4-5 unaccompanied refugee adolescents who will also be included. This group will be assisted by an interpreter.
• The children and adolescents do not have any physical impairment due to injuries or somatic illnesses (self-assessment).
• The children and adolescents are not acute suicidal. The responsible psychotherapists or supervisors of the "Schlupfhuus" will provide information about it.

For caregivers:

• Caregivers of children and adolescents, who experienced at least one PTE according to the DSM-5 definition of a traumatic event.
• The PTE(s) must have occurred at least 1 month ago.
• The child or adolescent must be between 1-18 years of age.
• Children and adolescents are either in trauma-focused therapy at the time of recruitment or they present with at least a moderate PTSS severity according to the Child and Adolescents Trauma Screen 2 (CATS-2).
• Caregivers must have sufficient command of the German language.
• The children and adolescents do not have any physical impairment due to injuries or somatic illnesses (self-assessment).
• The children and adolescents are not acute suicidal. The responsible psychotherapists or supervisors of the "Schlupfhuus" will provide information about it.

For clinical experts:

• Clinician or researcher specialized in trauma and PTSD in children and adolescents.
• Clinical experts must have sufficient command of the English language.

Exclusion Criteria:

• For children and adolescent participants:

  • Children and Adolescents who have not experienced at least one PTE according to the DSM-5 definition of a traumatic event.
  • The PTE(s) occurred before the fourth birthday.
  • The PTE(s) occurred less than 1 month ago.
  • Children and adolescents that are younger than 7 years old and older than 18 years old.
  • Children and adolescents that are neither in trauma-focused therapy at the time of recruitment nor meet the CATS-2 score for moderate PTSS severity or higher.
  • Children and adolescents that do not have sufficient command of the German language.
  • Children and adolescents that have physical impairment due to injuries or somatic illnesses (self-assessment).
  • Children and adolescents that are acute suicidal. The responsible psychotherapists or supervisors of the "Schlupfhuus" will provide information about it.

For caregivers:

• Caregivers of children or adolescents who have not experienced at least one PTE according to the DSM-5 definition of a traumatic event.
• The PTE(s) occurred less than 1 month ago.
• The child or adolescent is younger than 1 year old or older than 18 years old.
• The child or adolescent is neither in trauma-focused therapy at the time of recruitment nor meets the CATS-2 score for moderate PTSS severity or higher.
• Caregivers that do not have sufficient command of the German language.
• Children and adolescents that have physical impairment due to injuries or somatic illnesses (self-assessment).
• Children and adolescents that are acute suicidal. The responsible psychotherapists or supervisors of the "Schlupfhuus" will provide information about it.

For clinical experts:

• Clinical experts that don't work as clinician or as researcher specialized in trauma and PTSD in children and adolescents.
• Clinical experts that do not have sufficient command of the English language.

All the participants' informed consent must be obtained before any data is collected.

1. Children and adolescents (7-18years old) who experienced at least one traumatic event.
2. Caregivers of children and adolescents (1-18 years old) who experienced at least one traumatic event.
3. Clinical experts