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 sensitivity accompanied by an exaggerated intensity of behaviors whose purpose is to detect 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 hypervigilance, there is a perpetual scanning of the envi- ronment to search for sights, sounds, people, behaviors, smells, or anything else that is rem- iniscent of 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.
hypomania An abnormality of mood resembling mania but of lesser intensity. See also
MANIA.
hypopnea Episodes of overly shallow breathing or an abnormally low respiratory rate.
ideas of reference The feeling that causal incidents and external events have a particu- lar and unusual meaning that is specific to the person. An idea of reference is to be dis- tinguished from a DELUSION OF REFERENCE, in which there is a belief that is held with delusional conviction.
identity Experience of oneself as unique, with clear boundaries between self and others; stability of self—esteem and accuracy of self—appraisal; capacity for, and ability to regu- late, a range of emotional experience.
illusion A misperception or misinterpretation of a real external stimulus, such as hear- ing the rustling of leaves as the sound of voices. See also HALLUCINATION.
impulsivity Acting on the spur of the moment in response to immediate stimuli; acting on a momentary basis without a plan or consideration of outcomes; difficulty establish- ing and following plans; a sense of urgency and self—harming behavior under emotion- al distress. Impulsivity is a facet of the broad personality trait domain DISINHIBITION.
incoherence Speech or thinking that is essentially incomprehensible to others because word or phrases are joined together without a logical or meaningful connection. This disturbance occurs within clauses, in contrast to derailment, in which the disturbance is between clauses. This has sometimes been referred to a ”word salad” to convey the degree of linguistic disorganization. Mildly ungrammatical constructions or idiomatic usages characteristic of a particular regional or cultural backgrounds, lack of educa- tion, or low intelligence should not be considered incoherence. The term is generally not applied when there is evidence that the disturbance in speech is due to an aphasia.
insomnia A subjective complaint of difficulty falling or staying asleep or poor sleep quality.
824 Glossary of Technical Terms ological indicators of sex.
intimacy Depth and duration of connection with others; desire and capacity for close- ness; mutuality of regard reflected in interpersonal behavior.
intimacy avoidance Avoidance of close or romantic relationships, interpersonal attach- ments, and intimate sexual relationships. Intimacy avoidance is a facet of the broad personality trait domain DETACHMENT.
irresponsibility Disregard for—and failure to honor—financial and other obligations or commitments; lack of respect for—and lack of follow-through on—agreements and promises; carelessness with others’ property. Irresponsibility is a facet of the broad per- sonality trait domain DISINHIBITION.
language pragmatics The understanding and use of language in a given context. For example, the warning ”Watch your hands” when issued to a child who is dirty is in- tended not only to prompt the child to look at his or her hands but also to communicate the admonition ”Don’t get anything dirty." lethargy A state of decreased mental activity, characterized by sluggishness, drowsi- ness, inactivity, and reduced alertness.