"Shift work" is a term that applies to a wide array of nontraditional work 
schedules. Shift work disorder (SWD) is a circadian rhythm sleep disorder 
experienced by a subset of shift workers that is characterized by excessive 
sleepiness during work and/or insomnia during scheduled sleep times. It is 
estimated to affect up to 2 million Americans, and is associated with increased 
morbidity and mortality from metabolic risk factors, cardiovascular and 
gastrointestinal diseases, depression, accidents, and some kinds of cancers. 
Patient history is all that is needed to make a diagnosis with the International 
Classification of Sleep Disorders-Second Edition criteria as described herein. 
Circadian rhythm disorders, in which an underlying misalignment of circadian 
rhythm with the sleep-wake cycle occurs, may be treated by behavioral and 
pharmacologic approaches, including the use of hypnotics to improve the duration 
of sleep. However, evidence is limited with these approaches in patients 
diagnosed with SWD. Other treatment options may include pharmacologic 
interventions such as modafinil and armodafinil, which have shown efficacy in 
this population. Combined therapy can reduce insomnia and excessive sleepiness, 
and improve attention and alertness during work shifts and the subsequent 
commute home.