Insomnia and poor subjective sleep quality are associated with numerous adverse outcomes, including daytime distress and impaired psychosocial, physical and occupational functioning. Patients endure fatigue, lethargy, mood disturbances, poor cognitive performance, impaired motor functioning, social discomfort and a range of physical ailments.

For example, patients with primary insomnia showed longer response latencies and greater variability of responses in a battery of “challenging” tests of reaction times than controls. The severity of the objective and subjective sleep deficits seemed to predict the degree of impairment. Impaired reaction times are potentially hazardous when driving, operating heavy machinery or performing other complex tasks. Indeed, people with insomnia are more likely to have an accident than controls.

Poor sleep efficacy and shorter sleep duration also seem to reduce resistance to common illnesses. For example, patients who slept for less than 7 hours a night were 2.94 times more likely to develop the common cold than those who managed at least 8 hours. Patients who spent less than 92% of their time in bed asleep were 5.5 times more likely to contract a cold than those with at least 98% sleep efficiency.

References

Lemoine et al, 2007 Prolonged-release melatonin improves sleep quality and morning alertness in insomnia patients aged 55 years and older and has no withdrawal effects. J Sleep Res 2007-16:372/380

Edinger JD, Means MK, Carney CE, Krystal AD Psychomotor performance deficits and their relation to prior nights' sleep among individuals with primary insomnia Sleep 2008;31:599-607

Roth T Insomnia: definition, prevalence, etiology, and consequences J Clin Sleep Med 2007;3(5 Suppl):S7-10

Cohen S, Doyle WJ, Alper CM, Janicki-Deverts D, Turner RB Sleep habits and susceptibility to the common cold Arch Intern Med 2009;169:62-67