Introduction to insomnia disorder

The clinical picture of insomnia encompasses day- and night-time symptoms. Typical night-time complaints are prolonged sleep latency, increased frequency of awakenings, difficulties getting back to sleep and early morning awakening. Day-time sequelae encompass fatigue, tiredness, reduced attention, impaired cognition, irritability, nervousness, anxiety and mood swings, including dysphoric or even depressed mood. DSM-5 (Diagnostic and Statistical Manual of the American Psychiatric Association, 5th edition), ICSD-3 (International Classification of Sleep Disorders, 3rd edition) and ICD-11 (International Classification of Diseases, 11th edition) summarise this condition as Insomnia Disorder (ID). Epidemiological studies demonstrated that ID is an important risk factor for somatic and mental health. The prevalence of ID is higher in women than in men and increases with age. Apart from a clinical interview, questionnaires should be used for the evaluation of insomnia. The core instrument is a standardised 7-14 day sleep diary that includes questions on sleep-related and daytime symptoms. Actigraphy and polysomnography can be considered for a subgroup of patients presenting with therapy-refractory insomnia or suspected occult sleep disorders. A thorough medical and psychiatric evaluation is advisable to evaluate clinically relevant comorbidities. Present illness concepts range from genetic and neurobiological to cognitive-behavioral models, forming the basis for Cognitive Behavioural Therapy for insomnia (CBT-I) encompassing sleep hygiene and education, relaxation methods, stimulus control, sleep restriction and cognitive techniques to reduce nocturnal ruminations. Recently published guidelines agree that CBT- I should be the first line treatment for insomnia.