
TED-Ed
5 mins 13 secs
Ages 11 - 17
This video explores the psychological and biological mechanisms behind Post-Traumatic Stress Disorder (PTSD). It explains how trauma can lead to symptoms like flashbacks and nightmares, and discusses the role of the brain's fight-flight-freeze response and stress hormones in PTSD. The video also touches on the challenges of coping with PTSD and the factors that may contribute to its development.
Many of us will experience some kind of trauma during our lifetime. Sometimes we escape with no long-term effects, but for millions of us, those experiences linger, causing symptoms like flashbacks, nightmares, and negative thoughts that interfere with everyday life. This phenomenon, called Post-Traumatic Stress Disorder, or PTSD, isn't a personal failing. Rather, it's a treatable malfunction of certain biological mechanisms that allow us to cope with dangerous experiences. To understand PTSD, we first need to understand how the brain processes a wide range of ordeals, including the death of a loved one, domestic violence, injury or illness, abuse, rape, war, car accidents, and natural disasters. These events can bring on feelings of danger and helplessness, which activate the brain's alarm system, known as the fight-flight-freeze response. When this alarm sounds, the hypothalamic, pituitary, and adrenal systems, known as the HPA axis, work together to send signals to the autonomic nervous system. That's the network that communicates with adrenal glands and internal organs to help regulate functions like heart rate, digestion, and respiration. These signals start a chemical cascade that floods the body with several different stress hormones, causing physiological changes that prepare the body to defend itself. Our heart rate speeds up, breathing quickens, and muscles tense. Even after a crisis is over, escalated levels of stress hormones may last for days, contributing to jittery feelings, nightmares, and other symptoms. For most people, these experiences disappear within a few days to two weeks as their hormone levels stabilize. But a small percentage of those who experience trauma have persistent problems, sometimes vanishing temporarily, only to resurface months later. We don't completely understand what's happening in the brain, but one theory is that the stress hormone cortisol may be continuously activating the fight-flight-freeze response while reducing overall brain functioning, leading to a number of negative symptoms. These symptoms often fall into four categories: intrusive thoughts like dreams and flashbacks, avoiding reminders of the trauma, negative thoughts and feelings like fear, anger, and guilt, and reactive symptoms like irritability and difficulty sleeping. Not everyone has all these symptoms or experiences them to the same extent and intensity. When problems last more than a month, PTSD is often diagnosed. Genetics, ongoing overwhelming stress, and many risk factors like pre-existing mental illnesses or lack of emotional support likely play a role in determining who will experience PTSD. But the underlying cause is still a medical mystery. A major challenge of coping with PTSD is sensitivity to triggers—physical and emotional stimuli that the brain associates with the original trauma. These can be everyday sensations that aren't inherently dangerous but prompt powerful physical and emotional reactions. For example, the smell of a campfire could evoke the memory of being trapped.