Glossary of Technical Terms 823
of electric shocks and formication (the sensation of somethin g creeping or crawl-
ing on or under the skin).
visual A hallucination involving sight, which may consist of formed images, such as of
people, or of unformed images, such as fl ashes of light. Visual hallucinations should
be distinguished from ILLUSIONS , which are misperceptions of real external stimuli.
hostility Persistent or frequent  angry feelings; anger or irri tability in response to minor
slights and insults; mean, nasty, or vengeful  behavior. Hostility is a facet of the broad
personality trait domain ANTAGONISM .
hyperacusis Increased auditory perception.
hyperorality A condition in which inappropriate objects are placed in the mouth.
hypersexuality A stronger than usual urge to have sexual activity.
hypersomnia Excessive sleepiness, as evidenced by  prolonged nocturnal sleep, difficul-
ty maintaining an alert awake state during  the day, or undesired daytime sleep epi-
sodes. See also SOMNOLENCE .
hypervigilance An enhanced state of sensory sensit ivity accompanied by an exaggerated
intensity of behaviors whose purpose is to dete ct threats. Hypervigilance is also accompa-
nied by a state of increased anxiety which can cause exhaustion. Other symptoms include
abnormally increased arousal, a high responsiveness to stimuli, and a continual scanning
of the environment for threats. In hypervigilan ce, there is a perpetual scanning of the envi-
ronment to search for sights, sounds, people, beha viors, smells, or anything else that is rem-
iniscent of threat or trauma. The individual is placed on high alert in order to be certain