Diagnosis and Workup for Sleep Maintenance Insomnia

Primary Differential Diagnoses

Chronic insomnia disorder is defined by difficulty maintaining sleep or early-morning waking with inability to return to sleep, occurring ≥3 nights per week for ≥3 months, causing clinically significant distress or daytime impairment, and is more common in older adults and women, according to the American Academy of Sleep Medicine 1, 2
Advanced Sleep-Wake Phase Disorder (ASWPD) is characterized by falling asleep very easily in early evening hours and waking undesirably early, with patients reporting extreme difficulty staying awake during evening hours, as noted by the American Academy of Sleep Medicine 4, 5

A detailed sleep history is essential, including information on sleep patterns, daytime consequences, and circadian rhythm assessment, as recommended by the American Academy of Sleep Medicine 1, 4, 5
Sleep diaries and/or wrist actigraphy for ≥7 days are required to document sleep-wake patterns, as suggested by the American Academy of Sleep Medicine 4, 5, 6
Screening for comorbid conditions, including psychiatric assessment, medical history, and physical activity level, is necessary, according to the American Geriatrics Society 7

Assuming all sleep complaints are "just insomnia" without screening for OSA, RLS, or circadian disorders is a common mistake, as noted by the National Comprehensive Cancer Network 8
Ordering polysomnography for uncomplicated insomnia is not indicated and wastes resources, according to the American College of Physicians 2

Obtain a detailed sleep history using structured questions (duration ≥3 months, frequency ≥3 nights/week for chronic insomnia), as recommended by the American Academy of Sleep Medicine 1, 7
Document with sleep diary/actigraphy for ≥7 days, as suggested by the American Academy of Sleep Medicine 4, 5
Screen for depression, anxiety, medical conditions, and medications, according to the American Geriatrics Society 7
Reserve polysomnography for suspected OSA, narcolepsy, REM behavior disorder, or treatment-refractory cases only, as recommended by the American College of Physicians 2