Clinical Management of Insomnia

Abstract

Insomnia is the most common sleep disorder, with a prevalence of around 20%. The clearest risk factors are female gender and the presence of a psychiatric or medical disorder. The most important conceptual change in our understanding of insomnia, defined in the National Institutes of Health 2005 consensus conference, is that insomnia is a disorder itself rather than a symptom of another disorder. Specifically, insomnia is a disorder of hyperarousal. Insomniacs do not have an abnormal sleep homeostat or circadian system but rather an overactivated wake system. Cognitively, patients often complain they cannot “shut [their] brain down.” Physiologic correlates include elevated brain metabolism, increased fast electroencephalographic activity, and increased autonomic, metabolic, and hypothalamic-pituitary-adrenal axis activity. Treatment for insomnia can be divided into two categories, behavioral and pharmacologic. Another important categorization relates to self-treatment (sleep hygiene and over-the-counter drugs) versus clinician-directed therapy (cognitive-behavioral therapy for insomnia [CBT-I] and prescribed hypnotics). Among behavioral treatments are sleep restriction, stimulus control, relaxation training, and cognitive therapy. The most widely used behavioral therapy is a combination of the four treatment components referred to collectively as CBT-I. The majority of Food and Drug Administration (FDA)-approved hypnotics are drugs that occupy the benzodiazepine receptor site, which is part of the GABAA receptor complex. The hypnotic efficacy of the FDA-approved benzodiazepine receptor agonists (BzRAs) has been well documented using objective polysomnography and subjective measures of sleep induction and duration. Many BzRA side effects are associated with the desired sedative effects of the drug and relate to the pharmacokinetics, receptor subtype affinities, and dose of the drug. Key words: behavioral therapy, GABA, histamine, insomnia disorder, melatonin, orexin, pathophysiology, pharmacotherapy