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insomnia

A Dictionary of Psychology | Date: 2001

insomnia n. Inability to fall asleep or to maintain restful sleep, the condition usually being chronic. Initial insomnia (also called sleep-onset insomnia) is difficulty in falling asleep; middle insomnia is waking up in the middle of the night and having difficulty going back to sleep; and terminal insomnia is waking up at least two hours before one's normal waking time and being unable to fall asleep again. See also delayed sleep-phase syndrome, dyssomnias, fatal familial insomnia, primary insomnia. Compare hypersomnia, pseudoinsomnia.[From Greek insomnus sleepless, from in- not + somnus sleep + -ia indicating a condition or quality]


© A Dictionary of Psychology 2001, originally published by Oxford University Press 2001.