Teaching Topic
Insomnia Disorder
CLINICAL PRACTICE
J.W. Winkelman
Insomnia is the most common sleep disorder, with a reported prevalence of 10 to 15%, depending on the diagnostic criteria used. Reductions in perceived health and quality of life, increases in workplace injuries and absenteeism, and even fatal injuries are all associated with chronic insomnia. Difficulty maintaining sleep is the most common symptom (affecting 61% of persons with insomnia), followed by early-morning awakening (52%) and difficulty falling asleep (38%); nearly half of those with insomnia have two or more of these symptoms.
Clinical Pearls
 What medical conditions have been associated with insomnia?
Roughly 50% of those with insomnia have a psychiatric disorder, most commonly a mood disorder (e.g., major depressive disorder) or an anxiety disorder (e.g., generalized anxiety disorder or post-traumatic stress disorder). Various medical illnesses are also associated with insomnia, particularly those that cause shortness of breath, pain, nocturia, gastrointestinal disturbance, or limitations in mobility. Although roughly 80% of those with major depressive disorder have insomnia, in nearly one half of those cases, the insomnia predated the onset of the mood disorder. A meta-analysis of more than 20 studies concluded that persistent insomnia is associated with a doubling of the risk of incident major depression. Associations have also been reported between insomnia and increased risks of acute myocardial infarction and coronary heart disease, heart failure, hypertension, diabetes, and death, particularly when insomnia is accompanied by short total sleep duration (
Do the diagnostic criteria for insomnia distinguish between insomnia with and without coexisting psychiatric conditions?
Older diagnostic systems attempted to distinguish “primary” from “secondary” insomnia on the basis of the inferred original cause of the sleeplessness. However, because causal relationships between different medical and psychiatric disorders and insomnia are often bidirectional, such conclusions are unreliable. In addition, owing to the poor reliability of insomnia subtyping based on phenotype or pathophysiology, the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders takes a purely descriptive approach that is based on the frequency and duration of symptoms, allowing a diagnosis of insomnia disorder independent of, and in addition to, any coexisting psychiatric or medical disorders. The clinician should monitor whether treatment of such coexisting disorders normalizes sleep, and if not, treat the insomnia disorder independently.
Table 1. Criteria for the Diagnosis of Insomnia Disorder.
Morning Report Questions
Q. How is insomnia evaluated?
A. The evaluation of insomnia requires assessment of nocturnal and daytime sleep-related symptoms, their duration, and their temporal association with psychological or physiological stressors. Because there are many pathways to insomnia, a full evaluation includes a complete medical and psychiatric history as well as assessment for the presence of specific sleep disorders (e.g., sleep apnea or the restless legs syndrome). Questioning the patient regarding thoughts and behaviors in the hours before bedtime, while in bed attempting to sleep, and at any nocturnal awakenings may provide insight into processes interfering with sleep. A daily sleep diary documenting bedtime, any awakenings during the night, and final wake time over a period of 2 to 4 weeks can identify excessive time in bed and irregular, phase-delayed, or phase-advanced sleep patterns. Polysomnography is not indicated in the evaluation of insomnia unless sleep apnea, periodic limb movement disorder, or an injurious parasomnia (e.g., rapid-eye-movement [REM] sleep behavior disorder) is suspected or unless usual treatment approaches fail.
Q. What are some treatment options for chronic insomnia?
A. The choice of treatment of insomnia depends on the specific insomnia symptoms, their severity and expected duration, coexisting disorders, the willingness of the patient to engage in behavioral therapies, and the vulnerability of the patient to the adverse effects of medications. In patients with chronic insomnia, appropriate treatment of coexisting medical, psychiatric, and sleep disorders that contribute to insomnia is essential for improving sleep. Nevertheless, insomnia is often persistent even with proper treatment of these coexisting disorders. Treatment for chronic insomnia includes two complementary approaches: cognitive behavioral therapy (CBT) and pharmacologic treatments. CBT addresses dysfunctional behaviors and beliefs about sleep that contribute to the perpetuation of insomnia, and it is considered the first-line therapy for all patients with insomnia, including those with coexisting conditions. CBT is traditionally delivered in either individual or group settings over six to eight meetings. Several medications, with differing mechanisms of action, are used to treat insomnia. Benzodiazepine-receptor agonists include agents with a benzodiazepine chemical structure and “nonbenzodiazepines” without this structure. There is little convincing evidence from comparative trials that these two subtypes differ from each other in clinical efficacy or side effects. Because benzodiazepine-receptor agonists vary predominantly in their half-life, the specific choice of drug from this class is usually based on the insomnia symptom (e.g., difficulty initiating sleep vs. difficulty maintaining sleep). Regular reassessment of the benefits and risks of benzodiazepine-receptor agonists is recommended. The use of sedating antidepressants to treat insomnia takes advantage of the antihistaminergic, anticholinergic, and serotonergic and adrenergic antagonistic activity of these agents. At the low doses commonly used for insomnia, most have little antidepressant or anxiolytic effect. The orexin antagonist suvorexant, which was approved by the FDA in 2014 for the treatment of insomnia, showed decreased time to sleep onset, decreased time awake after sleep onset, and increased total sleep time in short-term randomized trials. Ramelteon is a melatonin-receptor agonist that is FDA-approved for the treatment of insomnia. Short-term studies as well as a controlled 6-month trial showed small-to-moderate benefits for time to sleep onset but no significant improvement in total sleep time or time awake after sleep onset. Meta-analyses of trials of melatonin for insomnia (at a wide range of doses and in immediate-release and controlled-release forms) showed small benefits for time to sleep onset and total sleep time. However, the quality control of over-the-counter melatonin products is unclear.
Table 2. Components of Cognitive Behavioral Therapy for Insomnia.
Table 3. Medications Commonly Used for Insomnia.
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Teaching Topic
Invasive Candidiasis
REVIEW ARTICLE
B.J. Kullberg and M.C. Arendrup
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