Hypervigilance as the brain’s protective mechanism

Andrii Solonskyi, MS in Psychology January 19, 2023

Phobos is the personification of fear in Greek mythology.



If you feel like you’re constantly on the lookout for danger but can’t explain why, hypervigilance may be to blame. Hypervigilance is the term used to describe a state of heightened awareness and increased sensitivity to potential threats, real or imagined. It can affect anyone at any time and often develops in response to an extreme situation, such as an assault or traumatic event.

While there are many types of anxiety disorders that involve experiencing anxiety about everyday situations (such as social anxiety), hypervigilance is unique because it involves being overly concerned about potential threats in your environment, even when no actual danger exists.

The definition of hypervigilance

Have you ever felt like you were on high alert, even when there was no immediate danger? If so, you may be experiencing hypervigilance.

Hypervigilance is a state of heightened awareness or vigilance in response to potential threats in the environment [1]. It’s an important survival mechanism that helps us stay safe when we experience danger or trauma [2]. When our brains sense that potential danger is present—even if it isn’t really there—we can feel anxious and even terrified as we prepare ourselves for a confrontation with whatever threat might be coming at us. We imagine what would happen if something bad happened, and this imagining can cause us to feel afraid and out of control [3].

Hypervigilance takes many forms: Anxious thoughts about how dangerous things could become; feelings of fear or dread; physical symptoms (like sweating) that make it seem like something terrible is about to happen; difficulty concentrating on daily tasks at work or school because your mind keeps going back to worrying about possible dangers; feeling constantly keyed up or on edge even though nothing dangerous has yet occurred around you.

The symptoms of hypervigilance

  • You feel on edge, tense, and anxious.
  • You’re easily startled.
  • You have trouble sleeping.
  • It’s hard to concentrate or focus on tasks.
  • Your memory and attention span decrease.

What can cause hypervigilance?

Hypervigilance can also be caused by mental health issues, such as PTSD, anxiety, and depression [3]. If you’re experiencing these symptoms, it’s important to talk to your doctor about them.

For example: if you have PTSD from an event that happened in the past (like a car accident), your brain may be triggered into overdrive when an unrelated event happens (like being rear-ended in traffic). The result is that you become hypervigilant even before any real threat arises.

In addition to mental health issues, traumatic experiences and ongoing stress are also known triggers for hypervigilance. For example: if someone with PTSD is walking down the street and sees a dog run out from behind a parked car, their body will react as though they are actually in danger of being attacked—even though there is no physical danger present in this scenario!

There are also a number of other triggers that can cause hypervigilance. For example: if you have a brain injury or some type of neurological disorder, your body may react as though it is being threatened even when there is no real danger present. Similarly, loneliness [4], substance abuse or addiction issues, and withdrawal symptoms can trigger hypervigilance as well. 

How do you know if you are suffering from hypervigilance?

Hypervigilance is a symptom of anxiety, depression and post-traumatic stress disorder. If you are hypervigilant without being aware of it, you may be suffering from a mental health disorder or an addiction.

If you are concerned about your own or someone else’s hypervigilance, here are some signs to look out for:

  • You find it difficult to relax and turn off your “fight or flight” response when there is no imminent danger.
  • You feel tense or plan escape routes even when confronted with benign situations like traffic jams or meetings at work.
  • You have trouble sleeping because your mind won’t stop racing with thoughts of possible dangers after the sun goes down (this is also known as “nightmare insomnia”).


If you feel like you’re living in a constant state of high alert and hypervigilance, there is good news. You can learn to manage your symptoms and even cure the condition altogether with proper treatment. The first step is awareness—being aware that something is wrong and taking action now.


  1. Terburg, D., Morgan, B. E., Montoya, E. R., Hooge, I. T., Thornton, H. B., Hariri, A. R., … & Van Honk, J. (2012). Hypervigilance for fear after basolateral amygdala damage in humans. Translational Psychiatry, 2(5), e115-e115.
  2. Zanette, L. Y., Hobbs, E. C., Witterick, L. E., MacDougall-Shackleton, S. A., & Clinchy, M. (2019). Predator-induced fear causes PTSD-like changes in the brains and behaviour of wild animals. Scientific reports, 9(1), 1-10.
  3. Kimble, M., Boxwala, M., Bean, W., Maletsky, K., Halper, J., Spollen, K., & Fleming, K. (2014). The impact of hypervigilance: Evidence for a forward feedback loop. Journal of anxiety disorders, 28(2), 241-245.
  4. Meng, J., Wang, X., Wei, D., & Qiu, J. (2020). State loneliness is associated with emotional hypervigilance in daily life: a network analysis. Personality and Individual Differences, 165, 110154.