Daytime sleepiness in insomnia patients
Introduction Insomnia patients, by definition, have disturbed or non-restorative sleep, and sleep less on average than the general population in terms of both self-reported and objective polysomnographic measures. As a result, it would be expected that insomnia patients suffer from at least some degree of sleep deprivation, and should thus have more daytime sleepiness than healthy controls. In this review we evaluate whether insomnia patients are, in fact, sleepier than healthy controls without insomnia. Daytime sleepiness in insomnia patients vs. healthy controls Self-report data A series of studies have been carried out comparing insomnia patients and healthy controls without sleep complaints on measures of daytime sleepiness. All 3 studies in the elderly and 2 in college students detected self-reported sleepiness, whereas sleepiness was found in just 4 out of 10 studies of middle-aged adults with primary insomnia. Nearly all of these studies were carried out with primary insomnia patients; however, two in middle-aged adults, one in older adults, and one in college-aged individuals included subjects with insomnia occurring comorbidly with other conditions. The measures used to assess sleepiness included the Stanford Sleepiness Scale, the Epworth Sleepiness Scale (ESS), and the vigor subscale of the Profile of Mood States. In addition, primary insomnia patients were found to have greater fatigue than good sleepers in four of six studies.