Anxiety and Insomnia – Bidirectional Associations
Abstract
David Nutt has consulted with and/or received grants and clinical trial payments from Pfizer (W-L), GlaxoSmithKline, MSD, Bristol-Myers Squibb, Esteve, Novartis, Asahi, Organon, Cypress, Lilly, Janssen, Takeda, Phamacia, Therasci, Passion for Life, Hythiam, Servier, Roche, sanofi-aventis, Actelion, Lundbeck Yamanouchi, AZ, P1vital and Wyeth. Professor Nutt has also received speaking honoraria from Reckitt-Benkiser and Cephalon. Sue Wilson has received funding from Solvay-Duphar, GlaxoSmithKline, MSD, Lundbeck, BMS, Pierre Fabre, Johnson & Johnson and Servier. She has given research talks in symposia funded by Organon, Pfizer, Wyeth and Lundbeck and participates on expert panels with honoraria from Takeda, Lundbeck and Servier. She has no financial interest in any pharmaceutical company and has had no contact with any pharmaceutical company regarding this article.Sleep, insomnia, GAD, anxiety, benzodiazepines
The link between anxiety and insomnia is forged by several different associations. People who suffer from insomnia have an increased incidence of anxiety disorder diagnosis, ratings of trait anxiety are higher in insomnia sufferers than in good sleepers and insomnia is one of the six core symptoms of generalised anxiety disorder (GAD).1 In addition, having insomnia can increase the risk of developing an anxiety disorder.
Insomnia is the subjective complaint of poor sleep, and may incorporate that: it takes too long to go to sleep, sleep is fragmented or interrupted or the amount of sleep achieved is too little overall. To reach a Diagnostic and Statistical Manual of Mental Disorders IV (DSM IV) diagnosis of insomnia, patients must have been experiencing difficulty sleeping for one month and this must cause clinically significant distress or an impairment in social, occupational or other important areas of functioning. Daytime symptoms include fatigue, lack of concentration, memory problems and low mood.
Anxiety is an integral element in insomnia, as worry about sleep is one of the main perpetuating factors influencing the development of chronic insomnia. Many people with insomnia suffer from mounting anxiety towards bedtime as fears about not sleeping and its possible next-day consequences become more salient. This increased anxiety leads to high arousal at a time when arousal levels should be decreasing, then a reduced chance of falling asleep, and thus a vicious cycle is engendered. Sufferers learn to associate their bedroom with not sleeping, so that going to bed in a strange environment is actually conducive to better sleep, whereas normal sleepers tend to have a worse night in a strange bed. As well as this sleep-focused anxiety, many studies of patients with insomnia find that the incidence of diagnosed anxiety disorders is higher than in good sleepers.
Anxiety Disorders in People with Insomnia
There have been some studies that have identified people with insomnia complaints or diagnosis and then examined the incidence of psychiatric disorders within these samples. In a population survey in France, about one-quarter of people who had an insomnia diagnosis also had a diagnosed anxiety disorder2 (mostly GAD). In a longitudinal study in young adults, Breslau et al. studied people with insomnia symptoms lasting for two weeks and found that approximately 8% of these had GAD.3
More common are studies of anxiety symptoms or trait anxiety in insomnia. In a study of older adults, Fichten et al.4 compared poor sleepers who experienced distress and those with similar reported poor sleep who experienced no distress. Questionnaires that rated low mood and state and trait anxiety showed the most difference between these groups, with the more distressed being the most anxious.
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