Psychometric measures in patients with primary insomnia and sleep state misperception.

Sleep state misperception (SSM) is a term used in the International Classification of Sleep Disorders to indicate people who mistakenly perceive their sleep as wakefulness. SSM is a classified as a form of primary insomnia. We measured psychometric parameters in primary insomnia, and evaluated their relationship with sleep perception. Seventy-six consecutive primary insomnia patients were enrolled; 34 men and 42 women, mean age 53.9±13.1. Sleep study included: Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Berlin’s Questionnaire, home-based polysomnography. Psychometric evaluation included: Self-Administered Anxiety Scale, Beck’s Depression Inventory, Maudsley’s Obsessive Compulsive Inventory, Snaith-Hamilton Pleasure Scale, Eating Attitude Test. All insomnia patients had psychometric scores higher than the general population, but very few patients, in both groups, had anxiety or depression scores consistent with severe mood or anxiety disorders. Comparisons between subjective and objective scores confirmed that most sleep parameters are underestimated. The study did not succeed in identifying any predictor of sleep misperception. We speculate that a group of patients, rather than being extremely worried by their insomnia, may have a sort of agnosia of their sleep.