How do stress, trauma and adversity affect the brain? Stress and trauma not only change our cognitive and psychological perspective but also our biology in terms of changes to the brain. Stress activates the “fight or flight” survival system and increases stress hormones and chemicals that if persistent/chronic, may lead to depression and post-traumatic stress disorder. These changes can be measured using modern brain imaging technologies (magnetic resonance imaging/MRI, electroencephalography/EEG) and with biological assays (blood, saliva) and can inform us about how stress impacts our biology and our response to stress, good and bad.