What Is The Fight Or Flight Response And How Does It Relate To Post-Traumatic Stress Disorder?

We've all heard of the "fight or flight" response, and though it isn't a complete way to describe ways in which people can react to potential or actual threats, it's fair to say that post-traumatic stress disorder causes those who live with it to always be ready for further danger, leading to symptoms that can be painful, awkward, and even dangerous in safe settings. 

What is the 'fight or flight response'? Another (and slightly different) look

In fact, here's what can happen:

• When faced with a perceived or actual threat, people can freeze. Something important catches their attention, so they immediately and automatically stop whatever they were doing and prioritize threat analysis.
• Next, research has found, is the urge to flee, to exit the dangerous situation. This makes sense for both humans and other animals, escape is less risky than physically fighting an enemy, carrying higher odds of survival. 
• If the escape attempt fails, fighting is the next option on the table. 
• Another option, called tonic immobility in psychological terms, is to "play dead" — which will certainly sound familiar to anyone who has ever heard any survival tips (right or wrong is besides the point right now) relating to sudden encounters with large wild animals. 

The "flight or fight response" is, therefore, ultimately a very incomplete way of describing what kinds of reactions people can have when they face a serious threat. In clinical terms, however, this fear response is termed hyperarousal, hypervigilance, or an acute stress response — and those things will very much be familiar to people who suffer from post-traumatic stress disorder. 

How hyperarousal impacts people with PTSD

If you look at the diagnostic criteria for post-traumatic stress disorder, as laid out in the DSM-5 (fifth edition of the diagnostic and statistical manual of mental disorders, the diagnostic "bible" used in the United States), you'll find several symptoms related to fear responses ("fight or flight", if you like). They'd include:

• Hypervigilance — which can be described as always being on guard, ready for further threats and danger. 
• An exaggerated startle response — reacting to stimuli that often turn out to be innocent and harmless as though they were threats. Examples might include the sound of fireworks or someone slamming a door, as well as sudden touch or seeing someone run by quickly. 
• Irritable and angry reactions that may lead to physical aggression towards people or things. 
• Reckless or self-destructive behavior.
• Trouble concentrating. 
• Trouble sleeping. 

It's been shown that memories of traumatic events aren't processed the way other memories are — rather than moving into different areas of the brain, they stick around in the subcortical and primary perceptual areas. A sudden trigger can then "reactivate" them, causing someone with PTSD to experience them as if they're happening in the presents. This accounts for the reexperiencing symptoms of PTSD, such as flashbacks, intrusive memories, and also nightmares. 

Post-traumatic stress disorder alters the memory and the brain, to the point where a person who suffers from it essentially never quite leaves the threat behind — even if the environment is now safe. In that state of mind, it's no wonder that people with PTSD can be stuck in a perpetual fear-response loop.

It becomes trouble — debilitating for the sufferer, and often for those around them too — when this fear response just doesn't go away, even in a safe situation, though. Then, a person reacts to things that aren't threats at all as though they were, and can themselves become a threat. 

What can be done to combat hyperarousal in PTSD?

Therapy can help people with post-traumatic stress disorder process their trauma in a safe situation, thereby integrating their trauma-related memories into their normal memory network. Though it is often a painful process that is likely to initially increase symptom severity, therapy can lead to significant symptom reduction.

Research has shown, however, that even people previously diagnosed with PTSD who complete treatment may continue to have hyperarousal ("fight or flight", if you want to use that term) responses. This is because brains that have experienced trauma are permanently changed — but sufferers can often learn to manage these fear response symptoms to the point where they are less debilitating for themselves and others.