This document discusses the rationale for developing trauma-informed service systems. It begins by defining psychological trauma and reviewing research showing high rates of trauma in vulnerable populations. Trauma affects brain development and can cause lasting negative impacts. The document advocates for a universal precautions approach and trauma-informed care across organizations, rather than just trauma-specific treatment. It outlines 12 criteria for building trauma-informed mental health systems, such as having trauma-focused policies, training staff, and involving trauma survivors. The goal is to minimize re-traumatization and promote healing.