Shift Work Sleep Disorder
What causes SWSD?
SWSD is caused by continued changes to a person's sleep-wake schedule. Most people demonstrate a remarkable ability to adjust to this repeated mismatching; however, individuals who experience persistent, severe symptoms are diagnosed as having SWSD.
How is SWSD diagnosed?
SWSD is usually diagnosed by means of an interview and a sleep study may also be useful. During the interview, the doctor will review the patient's sleep behaviours and experiences. This is known as the patient's 'sleep history'. A patient will usually consult their General Practionner following an episode of EDS, possibly during which he or she fell asleep at work or when driving.
The severity of SWSD can be evaluated using a sleep study. Ideally, the sleep study should be performed during the 'shifted' sleep period and the individual should be monitored in the work environment. A 24-hour recording over the first and last of the series of rotating shifts should be performed. In addition, the patient should be monitored during usual daytime wakefulness for a comparison.
Excessive Daytime Sleepiness in SWSD
As described previously, EDS is the primary symptom of SWSD and this impairs patients' performance at work, restricts or damages family and social lives, and damages general health. Owing to the need to perform at work and work in shifts, it is often not possible to implement simple solutions such as alteration of imposed sleep-wake schedules or nap taking.