to be considered pathological, avolition is pervasive and prevents the person from com-
pleting many different types of activities (e.g., work, intellectual pursuits, self-care).
bereavement The state of having lost through death someone with whom one has had
a close relationship. This state includes a range of grief and mourning responses.
biological rhythms See CIRCADIAN  RHYTHMS .
callousness Lack of concern for the feelings or problems of others; lack of guilt or re-
morse about the negative or harmful effects of one’s actions on others. Callousness is a
facet of the broad personality trait domain ANTAGONISM .
catalepsy Passive induction of a posture held  against gravity. Compare with WAXY  FLEX -
IBILITY .
cataplexy Episodes of sudden bilateral loss of mu scle tone resulting in the individual
collapsing, often occurring in association wi th intense emotions such as laughter, an-
ger, fear, or surprise.
circadian rhythms Cyclical variations in physiological and biochemical function, level
of sleep-wake activity, and emotional state. Circadian rhythms have a cycle of about 24
hours, ultradian rhythms have a cycle that is shorter than 1 day, and infradian rhythms
have a cycle that may last weeks or months.
cognitive and perceptual dysregulation Odd or unusual thought processes and experi-
ences, including DEPERSONALIZATION , DEREALIZATION , and DISSOCIATION ; mixed sleep-
wake state experiences; and thought-cont rol experiences. Cognitive and perceptual
dysregulation is a facet of the broad personality trait domain P SYCHOTICISM .
coma State of complete loss of consciousness.