Understanding and diagnosing shift work disorder.

A significant proportion of the workforce in industrialized countries (16%) are employed as shift workers. These workers may be susceptible to shift work disorder (SWD), a circadian rhythm sleep disorder, particularly those who work at night or on early-morning shifts. Shift work disorder remains an underdiagnosed and undertreated problem among this population. Patients with SWD have difficulty initiating sleep and waking up. Often, these patients have excessive sleepiness during their work shift. Shift work disorder has been associated with decreased productivity, impaired safety, diminished quality of life, and adverse effects on health. Several tools have been validated to assess excessive daytime sleepiness and are often used to assess excessive nighttime sleepiness, such as that experienced in patients with SWD, including the Epworth Sleepiness Scale and the Multiple Sleep Latency Test. The criteria for diagnosing SWD as established by the American Academy of Sleep Medicine (AASM) and published in the International Classification of Sleep Disorders-Second Edition (ICSD-2) were most recently updated in 2005 and thus do not contain newer agents approved for use in patients with SWD. The symptoms of SWD can be treated using behavioral, prescription, and nonprescription therapies. Current treatment guidelines suggest nonpharmacologic interventions, such as exercise and exposure to light. In addition, medications that contain melatonin or caffeine may have clinical benefits in some patients with SWD. However, modafinil and armodafinil are approved by the US Food and Drug Administration to improve wakefulness in patients with excessive sleepiness associated with SWD, and recent data suggest a clinical benefit. The use of these therapies can significantly improve sleep, performance, and quality of life for patients with SWD.