Nearly everyone suffers from an occasional night of poor sleep. For many, that occasional problem can become persistent and bothersome and can cause us to struggle as we attempt to optimize our daily lives. Despite better insomnia classification and recent evidence-based clinical guidelines, some evidence suggests that current classification systems do not fully capture the range of subjective sleep complaints. Recent research has focused on evaluating existing treatments for patients with primary insomnia. With the growing evidence base for nonpharmacological interventions for insomnia, recent studies have also aimed to evaluate the efficacy of these interventions in a broader range of patient populations.
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• Diagnostic classification systems of insomnia disorder have been revised, but correlation of these is difficult, and they may not capture the full range of subjective sleep complaints.
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• Compared to pharmacotherapy, cognitive behavioral therapy for insomnia is equally effective in the short term and has more durable effects.
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• Nonpharmacological treatments are effective for insomnia disorder when it is comorbid with other medical and psychiatric conditions.
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• The choice of pharmacologic agents should be directed by symptom pattern, treatment goals, past treatment responses, patient preference, cost, availability of other treatments, comorbid conditions, contraindications, and side effects.
Historical note and terminology
Insomnia, the difficulty in initiating or maintaining sleep, was first recorded in Egyptian medical papyri, with use of opium as a hypnotic to relieve insomnia and lavender as herbal sleep remedy in addition to its use for preserving mummies in the belief that death is eternal sleep (05). The ancient Indian text on Ayurvedic medicine, Charaka Samhita, written around 600 BC, describes herbal remedies for insomnia as well as nonpharmacological measures such as massage, warm bath, drinking milk, and listening to music. Although sleep disorders were known in ancient Chinese medicine, systematic description of these including insomnia was recorded in Huangdi Neijing (407-310 BC), with use of herbs and acupuncture for treatment. In Greek medicine, insomnia is reflected in Aristotle’s writings on sleeplessness in 350 BC (15). In Arab medicine, Avicenna’s Canon of Medicine, which was written in 1632 AD, described behavioral as well as pharmacological approaches for the treatment of insomnia.
Unless otherwise stated, the term “insomnia” refers to chronic insomnia, which is present for at least a month, in contrast to acute or transient insomnia, which may last days. The nature of its variable consideration as a symptom, complaint, disorder, disease, or consequence of other primary disorders has contributed to the difficulty in creating an effective approach to diagnosis and treatment. Insomnia appears in several forms: (1) difficulty initiating sleep, (2) repeated or lengthy awakenings, (3) early awakenings, (4) inadequate total sleep time, or (5) poor quality of sleep as reflected by its consequences, including daytime sleepiness. Other factors that contribute to a difficulty in diagnosis are the issues of individual variation in sleep need, along with the difference between the subjective assessment and objective measurements of sleep in a patient.
Unfortunately, the classifications and nomenclature used by physicians lack uniformity of approach. Three major classification systems used by professionals are as follows:
The International Classification of Diseases is published by the World Health Organization (30). It is the most widely used classification system for reporting diseases and causes of death. Part of its widespread utilization is its mandatory status for official reporting in the World Health Organization member states.
The International Classification of Sleep Disorders – 3rd Edition (ICSD-3) was published by the American Academy of Sleep Medicine and is increasingly used by sleep physicians in the United States (02). The classification of insomnia disorders in ICSD-3 is a marked departure from that of prior systems. In ICSD-1 and ICSD-2, primary insomnia was further subtyped into psychophysiologic, idiopathic, and paradoxical (sleep-state misperception) insomnia disorders. The diagnostic reliability and validity of insomnia diagnoses, especially primary insomnia, have been challenged on the basis of several studies, and the ICSD-3 has included all insomnia diagnoses, ie, primary and comorbid, under a single, chronic insomnia disorder (23). The 3 categories now are:
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(1) Chronic insomnia disorder
(2) Short-term insomnia disorder
(3) Other insomnia disorder
The Diagnostic and Statistical Manual of Mental Disorders (5th ed, DSM-V) has been produced by the American Psychiatric Association and is more likely to be used by biological and psychiatric specialists (03). DSM-V emphasizes the need for independent clinical attention of a sleep disorder regardless of mental or other medical problems that may be present. Two previous diagnoses—sleep disorder related to another mental disorder and sleep disorder related to another medical condition—have been eliminated, and greater specificity of coexisting conditions is provided for each of the 10 sleep-wake disorders defined, including insomnia. DSM-V also replaces primary insomnia with the diagnosis of insomnia disorder, a switch to avoid the primary/secondary designation when this disorder co-occurs with other conditions and to reflect changes throughout the classification.
Unfortunately, there is no uniform agreement or ability to match the various diagnostic categories in insomnia effectively across the 3 classification systems. In general, the ICSD-3 has more specificity, and the new reorganization makes it much easier to use.
Despite the availability of 3 different classification systems for insomnia, some sleep complaints do not fit into any diagnostic category.