Sixty percent of children in the US have experienced trauma, as have seventy percent of adults. The experience of trauma changes how the brain develops during childhood, and changes the brain’s structure and function in adulthood (even in the absence of childhood trauma). This presentation will provide a brief overview of childhood brain development, brain structure and function, how the emotional brain and the rational brain are connected and work together, and the impact of trauma and mental illness on different brain systems. We will look at various types of brain scans in individuals of different ages to understand how trauma and associated mental illnesses, such as depression or PTSD, change the structure and function of the brain, with an emphasis on what these changes look like behaviorally. Finally, we will discuss what providers, caregivers, and others working with the individual can do to minimize the impact of trauma on the brain and help the brain, and its person, recover.