Insomnia and Circadian Rhythm Sleep-Wake Disorders
Insomnia
Insomnia is difficulty initiating or maintaining sleep, or early awakening, with daytime consequences despite adequate opportunity for sleep. It is diagnosed clinically; PSG is not routine. Cognitive behavioral therapy for insomnia (CBT-I) is first-line, combining stimulus control, sleep restriction, and cognitive restructuring. Hypnotics are adjunctive and carry dependence and fall risks, especially in older adults.
Circadian rhythm disorders
Delayed sleep-wake phase disorder is common in adolescents; advanced sleep-wake phase disorder in older adults. Shift work disorder and jet lag reflect misalignment with the external environment. Treatment uses timed bright light, melatonin at the appropriate circadian phase, and behavioral scheduling. Melatonin is a chronobiotic, not a hypnotic; timing matters more than dose.
Traps
- Sleep state misperception may be mistaken for severe insomnia; actigraphy can help.
- Melatonin given at the wrong time can worsen phase problems.
- Shift work disorder requires symptoms plus a work schedule misaligned with circadian timing.
- Do not use sleep restriction in patients with bipolar disorder without caution.
Rule of thumb
CBT-I first for chronic insomnia; light and timed melatonin first for circadian phase disorders.