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  1. GeneviÈVE Belleville1,
  2. Charles M. Morin2

Published Online: 30 JAN 2010

DOI: 10.1002/9780470479216.corpsy0445

Corsini Encyclopedia of Psychology

Corsini Encyclopedia of Psychology

How to Cite

Belleville, G. and Morin, C. M. 2010. Insomnia. Corsini Encyclopedia of Psychology. 1–3.

Author Information

  1. 1

    University of Quebec at Montreal

  2. 2

    Laval University Canada

Publication History

  1. Published Online: 30 JAN 2010


Insomnia entails a spectrum of complaints reflecting dissatisfaction with the quality, duration, or continuity of sleep. These complaints may involve problems with falling asleep initially at bedtime (initial insomnia), waking up in the middle of the night and having difficulty going back to sleep (middle insomnia), awakening prematurely in the morning with an inability to return to sleep (late insomnia), or a perception of nonrestorative sleep. In order to fulfill the American Psychiatric Association (APA) diagnostic criteria of an insomnia disorder (e.g., Primary Insomnia, Insomnia related to another mental disorder), the sleep disturbance or its daytime consequences (e.g., fatigue) have to cause significant psychological distress or impaired functioning (APA, 2000). More than one third of the adult population reports insomnia symptoms, whereas 6% suffer from an insomnia disorder (Ohayon, 2002).


  • insomnia;
  • sleep;
  • sleep disorders