Trauma is any experience that poses a threat to someone's physical or emotional safety. We often have certain things we think about when we think of what trauma is (eg: physical/sexual abuse, war), but it can also be other types of abuse, high-crime environments, oppression, bullying, etc. Anything that can make a person feel unsafe can be trauma, although not all those experiences will make someone develop PTSD. Two people who go through the same thing may have different reactions, such as one develops PTSD whereas one doesn't.
Fight, Flight, Fawn, or Freeze?
These are the four trauma responses that are noted in people. Fight and flight are the most commonly known, as they present in other circumstances as well (like in anxiety). They come from the brain's natural desire to survive, causing chemicals in the brain to release (adrenaline is one of them) and pushing you into survival mode. In the fight version of survival mode, you'll try to fight back against the situation (think if you're confronted by a lion, in the fight response, you would try to fight it). Flight is the response where you try to run away from the situation (think running from the lion). Fawn is kind of like trying to appease to the situation, like appeasing to abusers to avoid further abuse. Freeze is when your body/mind freezes, not doing anything to try and prevent it but instead protecting yourself more internally. You can experience multiple of these, and it's likely it'll change based on the situation.
Fight response examples would include: anger outbursts, insulting/mocking/taunting/shaming, becoming aggressive, easily reactive, always feels as though you're threatened, feeling shameful after outbursts, and/or "talking back" to authority figures
Flight response examples would include: chronic rushing or "always going", feeling uncomfortable even when still, energy spent managing things around you, fear of commitment/abruptly ending relationships, easily feeling trapped, making plans to avoid downtime, throwing yourself into work/achievement, being distracted, and/or often presenting as anxiety/panic attacks
Fawn response examples would include: avoiding conflict, going along with others' beliefs (even if not your own), dissociation, letting others make decisions, fearing saying "no", overly polite/agreeable, hyperawareness of others' needs and emotions while betraying your own, and/or relying on others to solve problems
Freeze response examples would include: feeling completely numb, shutdown, complete avoidance, hiding out from the world, procrastination, inability to make even small decisions, endless social media scrolling/binge watching, and/or confusion over what's real and imagined
Disorders caused by trauma
Trauma itself isn't a disorder, but it leads to many. The most commonly known one is PTSD, but there are many more. Depression, anxiety, C-PTSD, substance abuse disorders, somatoform and somatization disorders, eating disorders, psychosis, Acute Stress Disorder, adjustment disorders, Reactive Attachment Disorder, Disinhibited Social Engagement Disorder, personality disorders, dissociative disorders, etc. are all linked to trauma, although not all are only caused by trauma.
Trauma's Effect Years Later
Trauma impacts the ability to identify, regulate, and express emotions and can have a significant impact on the individual's core identity. This is because during those events, the brain doesn't know how to feel. Obviously it feels scared and in need for survival, but there's also hope to survive, anger that it happens, sadness, etc. With all those conflicting emotions at once, the brain gets overwhelmed. This is why dissociation is so common in trauma survivors. We and many other people have noticed that we tend to dissociate more when we're safe, which didn't make sense for the longest time. However, we finally put it together. During trauma, the brain becomes used to being in the high-stress state, so used to it in fact that it sometimes finds the non-stressful things even more stressful. Your brain wants to stick with what it knows, so it feels the peace and safety is a threat.