Cognitive-behavioral Therapy for Insomnia

Insomnia is defined as having 2 or more weeks of sleep difficulties, and approximately 9–18% of American adults suffer from the disorder.1-6 The morbidity rate in Korea is similar to that in America, ranging from 10–17%.7 Chronic insomnia is associated with the following symptoms: daytime fatigue, decrease in memory and concentration, negative mood, lower quality of life, higher rates of absence from work, increase in medical costs, depression, and long-term consumption of sleeping pills.8-13 In the past, DSM-IV-TR categorized insomnia into two subtypes; primary insomnia and secondary insomnia. Primary insomnia was considered the most classical form of insomnia, which is learned or conditioned when sleep disturbance is caused by sleep-interfering behaviors and cognitive and physiological hyperarousal, including factors such as psychological distress and excessive worry about sleep. On the other hand, secondary insomnia is comorbid with other sleep, physical, or mental disorders. According to research by Ford and Kamerow,1 the largest number of people who have comorbid insomnia are those with psychiatric disorders. Based on research that most individuals with insomnia have comorbid disorders, DSM5, which was released in 2013, combined the two terms (primary and secondary insomnia) into “insomnia disorder.”14 Based on the new DSM-5, clarification of the presence of comorbid disorders is mandatory.