Hypervigilance is an enhanced state of sensory sensitivity accompanied by an exaggerated intensity of behaviors whose purpose is to detect activity. Hypervigilance may bring about a state of increased anxiety which can cause exhaustion. Other symptoms include: abnormally increased arousal, a high responsiveness to stimuli, and a constant scanning of the environment.
In hypervigilance, there is a perpetual scanning of the environment to search for sights, sounds, people, behaviors, smells, or anything else that is reminiscent of activity, threat or trauma. The individual is placed on high alert in order to be certain danger is not near. Hypervigilance can lead to a variety of obsessive behavior patterns, as well as producing difficulties with social interaction and relationships.
Hypervigilance is differentiated from dysphoric hyperarousal in that the person remains cogent and aware of their surroundings. In dysphoric hyperarousal, a person with PTSD may lose contact with reality and re-experience the traumatic event verbatim. Where there have been multiple traumas, a person may become hypervigilant and suffer severe anxiety attacks intense enough to induce a delusional state where the effects of related traumas overlap. This can result in the thousand-yard stare.
Hypervigilance can be a symptom of post traumatic stress disorder (PTSD) and various types of anxiety disorders. It is distinguished from paranoia. Paranoid diagnoses, such as can occur in schizophrenia, can seem superficially similar, but are characteristically different.