Secondary traumatic stress is currently not listed as a diagnosis in the DSM-5-TR or ICD-11. It occurs when someone experiences stress or emotional strain after hearing about or witnessing the trauma of others. It often happens to people who care for or work with those who have gone through difficult experiences, like doctors, therapists, or first responders. It can cause feelings like anxiety, sadness, or being overwhelmed, similar to what the person directly affected by the trauma might feel.