抄録
Insomnia symptoms (difficulty initiating sleep, difficulty maintaining sleep, and early morning awakening) are
common, with a prevalence of 20% in the Japanese general adult population. In this paper, the author describes
the clinical steps in the differential diagnosis of insomnia symptoms for readers who are not specialized in sleep
medicine. When patients complain of insomnia symptoms, physicians first need to check their sleep habits and
optimize them if they are inappropriate and interfere with good sleep. Medical history and medication use should
also be reviewed in the first step because some medical conditions (e.g., articular diseases, skin diseases, cardiopulmonary disorders) and medications (e.g., steroids, interferon, methyldopa, levodopa) can cause insomnia
symptoms. Insomnia symptoms can be caused by a variety of sleep disorders other than insomnia disorders, such
as obstructive sleep apnea, restless legs syndrome, periodic limb movement disorder, and delayed sleep-wake
phase disorder. A diagnosis of insomnia disorder is given only if the insomnia symptoms cannot be fully explained
by another sleep disorder.
