Sleep Disorder, Shift Work (Shift Work Disorder, SWD)

BASICS

Definition:
Circadian rhythm sleep-wake disorder, characterized by insomnia and/or excessive sleepiness due to misalignment between internal circadian rhythms and required sleep-wake schedules from nontraditional work shifts (night, evening, early morning, rotating, irregular).
Systems affected: nervous, cardiovascular, metabolic

Prevalence:
20% of U.S. employed adults are shift workers (esp. healthcare, transportation, food services, protective services)
1 in 3 shift workers experience insomnia or sleep disturbance; ~90% report daytime sleepiness/fatigue
Estimated SWD prevalence: 2–5% in the general U.S. population
Risk increases with age (>50 years)

Pathophysiology:
Circadian misalignment between endogenous rhythms and nontraditional sleep-wake schedules leads to sleep onset/maintenance insomnia and/or excessive sleepiness during required awake hours
Genetics:
Morning/evening preference partially linked to polymorphisms of the PER3 clock gene

Impaired recall, decreased processing speed, attention deficits
Increased risk: vehicular/work accidents, GI disorders, CVD, diabetes, possible cancers
Higher rates of mood disorders and substance use

Persistent/recurrent sleep disruption due to circadian misalignment (physical/social/professional)
Leads to excessive sleepiness and/or insomnia
Causes significant distress/impairment in functioning

Insomnia during sleep period and/or excessive sleepiness during awake period tied to shift work
Classified as: episodic (1–3 mo), persistent (>3 mo), or recurrent (≥2 episodes/year)

Assess for mood disorders, obesity/large neck (OSA risk), CVD, diabetes, GI disease

Primary insomnia, sleep-related breathing disorders, central hypersomnolence, parasomnias, movement disorders
Other circadian rhythm disorders (delayed sleep phase, irregular sleep-wake)

Diagnosis is clinical; no routine labs
Consider polysomnography or multiple sleep latency test if other sleep disorder suspected
2-week sleep diary, Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS) can aid in assessment

Sleep hygiene:
Minimize light before/during sleep (dark room, blackout shades, sunglasses after shift)
Quiet, cool environment, white noise, ear plugs
Avoid stimulants during latter half of shift
Scheduled/protected sleep:
Anchor sleep (consistent sleep blocks overlapping work/nonwork days)
Strategic naps (<1 hour) before/during shift (beware post-nap sleep inertia)
Lifestyle:
Manage stress/depression, healthy diet, regular exercise (avoid within 2–4h of bedtime), limit substances
Social support for sleep protection
Work modifications:
<4 consecutive shifts, shift duration <12h, >11h between shifts, avoid heavy work during circadian nadir (4–7am)

Bright light therapy (>2,000 lux, blue wavelengths) during shift to promote alertness
Light avoidance after shift to promote daytime sleep

Sleep-promoting:
Melatonin 3 mg (AASM recommended), 30 min before daytime sleep
Ramelteon (Rozerem), doxepin (low-dose), trazodone (second-line), nonbenzo hypnotics (zolpidem, eszopiclone, suvorexant)—short-term only
Wakefulness-promoting:
Modafinil 200 mg or armodafinil 150 mg 1h before shift (FDA approved for SWD)
Prophylactic caffeine (first half of shift only)
Note:
Long-term use of hypnotics not recommended; risk of dependence and residual sedation

Modafinil/armodafinil before shift, hypnotics before daytime sleep, short-term low-dose antidepressants if needed

Sleep specialist for suspected primary sleep disorders, hypnotic/stimulant dependence, or persistent symptoms

Patient education on sleep hygiene, environment optimization, risk of accidents with sleep loss
Encourage use of sleep diary
Symptoms resolve if shift work is eliminated (not always feasible)