Insomnia is highly prevalent in psychiatric disorders, and it has significant implications. This review focuses on insomnia in the context of anxiety disorders. The prevalence of comorbid insomnia in anxiety disorders is addressed and the clinical implications associated with insomnia are discussed as well as when and how to treat this important comorbidity.
Just how specifically insomnia relates to and possibly affects anxiety disorders is highlighted by the fact that insomnia is one of the defining criteria in a number of the DSM-IV-TR anxiety disorders. For example, difficulty in falling or staying asleep is a criterion for PTSD, acute stress disorder, and generalized anxiety disorder (GAD).
The relationship of insomnia to anxiety disorders is also influenced by comorbid major depression. The severity of insomnia is increased when an anxiety disorder is comorbid with a major depressive disorder (MDD).1 This is highly relevant because 58% of MDD patients have a lifetime anxiety disorder.2
The presence of insomnia has a deleterious effect on daytime functioning and negative effects on quality of life, including social and work relationships.3 Also, there is clear evidence that the presence of insomnia in anxiety disorders is associated with increased morbidity. For example, in patients with PTSD, insomnia is associated with an increased likelihood of suicidal behavior, depression, and substance abuse as well as nonresponsiveness to treatment.4-6 In addition, insomnia as an early symptom in traumatized patients increases the risk of the development of PTSD 1 year later.7
It is important to carefully assess for insomnia early in the evaluation of patients with anxiety disorders and to aggressively treat this complicating comorbidity. Insomnia is an underrecognized and undertreated problem. Patients rarely report their symptoms of insomnia spontaneously to their doctor. Adding to the problem of detecting insomnia is the finding that doctors rarely inquire about insomnia in their patients.3,8,9 Thus, a carefully taken history is an important first step in the assessment of insomnia.
Self-rating sleep questionnaires and direct clinical interviews are used to obtain a history of potential sleep disorders (eg, insomnia). A number of well-validated sleep questionnaires have been widely used. The most widely used and validated questionnaire is the 19-question Pittsburg Sleep Quality Index. The questions cover sleep quality, sleep problems, sleep medications, and so on, within the past month.10 Another widely used questionnaire is the Leeds Sleep Evaluation Questionnaire (LSEQ). The LSEQ consists of 10 self-rating questions that cover sleep and aberrant sleep behaviors.11
Besides self-rating questionnaires that depend on memory of sleep disturbances, a sleep log or diary can confirm questionable sleep disturbances prospectively. The use of a sleep log allows for an analysis of day-to-day sleep patterns, such as the time that the patient went to bed, sleep latency, and nighttime awakenings.8,9 The log is filled out by the patient shortly after awakening in the morning (see Morin9(p38) for an example of a sleep log). If at all possible, monitoring for up to 2 weeks is highly recommended because it allows for sleep abnormalities that might show marked day-to-day variability and would more likely be detected by extensive monitoring.12,13
What is already known about insomnia
in patients with anxiety disorder?■ Anxiety disorders frequently coexist with insomnia. The latter is believed to be part and parcel of various anxiety disorders and is one of the defining criteria of a number of them.
in patients with anxiety disorder?
What new information does this article provide?■ Our article clarifies new approaches to considering insomnia in anxiety disorders. The presence of insomnia should be considered a comorbid illness and treated on its own. Pharmacotherapy, cognitive-behavioral therapy, and a combination of both are discussed. Insomnia is an added pathology that brings increased morbidity to patients with anxiety disorders. Our review suggests that successful treatment of insomnia actually increases the responsiveness of anxiety disorders to many antianxiety treatments.
What are the implications for psychiatric practice?■ When evaluating patients with anxiety disorders, psychiatrists should carefully evaluate for the presence of insomnia. Patients infrequently bring up this symptom on their own. If insomnia is present, aggressive treatment early in the course of therapy is highly suggested.
If the presence of insomnia is suspected, interviewing a spouse, a significant other, or a caregiver is helpful. Some patients who believe they have insomnia symptoms appear to have “sleep state misperception,” where their partners clearly state that their sleep is normal.14 These “others” can also report problems that are likely not obvious to the patient:
• Apnea spells or excessive snoring as seen in obstructive apnea
• Excessive body movements as seen in periodic leg movement disorder and restless legs syndrome
• Various sleep-related behaviors (sometimes violent and aggressive) as seen in rapid eye movement behavior disorder (RBD)
Referral to a sleep specialist and sleep polysomnography has been recommended if pharmacological or nonpharmacological options are not working. Referral is also warranted for patients with insomnia in whom a specific sleep disorder, such as obstructive sleep apnea, periodic limb movements, narcolepsy, or RBD, is suspected.12,15 Even when a visit to a sleep laboratory is suggested, the cost of an overnight visit is often prohibitive—more than $1000 per night; usually 2 nights are required with the first being an adaptation night for the patient. Insurance frequently does not cover these costs.16 If it is found that the patient has sleep apnea, a sleep movement disorder, RBD, or a number of other sleep disorders, specific nonhypnotic treatments may be required (eg, continuous positive airway pressure for sleep apnea is the treatment of choice).