Presentation and course
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• The diagnostic criteria for anxiety includes reports of sleep disturbance, including insomnia, restlessness, or unsatisfying sleep. |
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• Most patients with post-traumatic stress disorder (PTSD) suffer from insomnia and nightmares. |
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• Sleep and anxiety have a bidirectional relationship, in that anxiety disorders are associated with causing sleep issues and sleep issues can bring on anxiety disorders. |
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• Individuals with anxiety disorders have objectively shorter sleep, more wake after sleep onset, and more frequent arousals during the night. |
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• Insomnia is a more common feature in individuals with severe panic disorder, and approximately 20% have panic attacks predominantly at night. |
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• Chronic sleep problems are also a risk factor for developing anxiety disorders. |
The DSM-5-TR differentiates anxiety from fear. Although fear is the emotional response to a real or perceived imminent threat, anxiety is the anticipation of a future threat. Fear is more associated with the well-known fight or flight response from activation of the autonomic arousal system, whereas anxiety exhibits more vigilance, tension, and restlessness. Both of these emotional states become pathological when they no longer serve an appropriate function, and they start to cause pervasive distress or impairment of day-to-day functions and social interactions. These emotional responses and associated behaviors can be provoked by a variety of objects, events, and situations.
Anxiety and fear-based disorders are frequently associated with sleep complaints, notably, difficulty initiating and maintaining sleep, restless nonrestorative sleep, and short sleep duration. One of the diagnostic criteria for anxiety includes a report of sleep disturbance, which can vary from insomnia, restlessness, or unsatisfying sleep. For example, between 70% to 90% of individuals suffering from PTSD report a sleep disturbance, including nightmares and insomnia. PTSD has also been found to be associated with obstructive sleep apnea (OSA) (27). This relationship is bidirectional, in that anxiety disorders are associated with causing sleep issues and sleep issues can bring on anxiety disorders. Chronic sleep problems are also a risk factor for developing anxiety disorders. Some studies have highlighted the independent and bidirectional relationships between anxiety, fear, and sleep disturbances. Cousins found, in youth aged 8 to 16 years, a relationship of daytime affect to subsequent nighttime sleep (10). In addition, more time asleep during the night was associated with more positive next-day affect (10). This bidirectional relationship has been more recently shown with the COVID pandemic. Since the COVID-19 pandemic, there have been several studies looking at stress, anxiety, and sleep problems stemming from its aftermath. There have been between 20% to 45% of reported insomnia cases during the pandemic (03). These studies have shown that there are now higher rates of insomnia, stress, anxiety, and depression than previously noted since the start of the pandemic (28). Research has historically shown that stressful events have a more profound impact on individuals with insomnia than those with normal sleep. One study found that individuals with acute insomnia symptoms during the pandemic had a stronger likelihood of having anxiety and depression than in individuals with preexisting or chronic insomnia (03). Sleep problems were also seen in individuals who contracted COVID-19. Individuals who were hospitalized with the infection for 7 or more days complained of disturbed sleep and excessive daytime sleepiness, and these symptoms lasted for months after recovery (03).
Each anxiety and trauma disorder have varying presentations in their sleep disturbances. Definitions for these disorders are based on the DSM-5-TR criteria. These presentations are described below:
Generalized anxiety disorder. Anxiety is the most common mental health disorder, with a global prevalence of around 25% (09). The defining feature of generalized anxiety disorder is excessive anxiety and worry occurring for at least 6 months on most days in various environments, such as school or work. These individuals find it difficult to control these feelings, thus causing disruption in their day-to-day life. Many of these patients find these pervasive thoughts persisting into their bedtimes, thus affecting their sleep. They often report sleep initiation and maintenance insomnia.
Panic disorder. Sleep problems are common in panic disorder. Individuals with severe panic disorder have significantly higher prevalence of insomnia (24). Sleep onset problems may be particularly pronounced among panic disorder patients with high levels of anxiety sensitivity, defined as excessive fear of anxiety-related sensations (22).
Panic disorder is characterized by recurrent and unexpected panic attacks, which are sudden increases in intense fear or discomfort that reaches a peak within minutes. Patients often endorse palpitations, sweating, chest pain, sensation of dyspnea, trembling, nausea, abdominal discomfort, or dizziness. Some may also have a feeling of losing control or uncontrolled fear of dying. These episodes tend to be self-limiting and brief, usually lasting from 10 to 30 minutes.
Panic attacks can occur as a part of various mental disorders, or they can be isolated events. Panic attacks can occur in the transition between wake and sleep. Sleep complaints tend to be most severe in patients with nocturnal panic attacks, which are recurrent in 33% of patients (19). Nocturnal panic attacks begin with an abrupt arousal from sleep without dream mentation and are accompanied by panic attack symptoms that are similar in severity and duration to panic attacks experienced while awake, although in some patients, panic attacks may be experienced predominantly or exclusively during sleep (37). These nocturnal episodes are distinguishable from sleep terrors, sleep apnea, nightmares, or dream-induced arousals by the fact that the patients with panic become fully awake and aware of their surroundings and have memory for the events. In some patients, nocturnal panic attacks may lead to a phobic fear of the sleep environment or sleep itself, leading to avoidance of sleep.
Social and specific phobia. Individuals with social phobia have marked and persistent fear of one or more social situations where they may be scrutinized by others. Specific phobias exhibit the same persistent fear, but for specific objects or situations. These individuals do not tend to have sleep problems, unless the contents of their phobia is related to sleep. Although little systematic investigation has been conducted, one study found that as many as two thirds of a sample of treatment-seeking patients with social phobia reported insomnia symptoms, with one third falling in the moderate to severe range (34).
Posttraumatic stress disorder. Posttraumatic stress disorder (PTSD) is diagnosed when an individual is exposed to an actual or threatened death, serious injury, or sexual violence, and begin to have recurrent and intrusion memories of these events. This includes intrusive dreams or nightmares. Individuals will attempt to avoid these stimuli linked to the traumatic event, thus leading to avoidance of sleep to prevent a nightmare. A systematic review of nightmares in individuals with psychiatric conditions suggested that the presence of nightmares lead to an increased the risk of suicidality and that treatment of the nightmares could mitigate that risk (39).
In addition to a high prevalence of nightmares in patients with PTSD, dream enactment behavior (DEB) is also noted to be common in these patients (26). REM sleep behavior disorder (RBD) is the phenomenon of the loss of atony with punching, kicking, yelling, and/or screaming in REM sleep corresponding with dream content. REM sleep behavior disorder can also be seen in patients with obstructive sleep apnea or patients on antidepressants. Dream enactment behavior along with REM sleep without atonia (RSWA) is seen on polysomnography. REM sleep behavior disorder is associated with the development of a group of disorders known as alpha-synucleinopathies, including Parkinson disease, multiple system atrophy, and dementia with Lewy bodies (42). Interestingly, Feemster and colleagues in a retrospective study showed that patients with PTSD had increased RSWA regardless of the presence or absence of dream enactment behavior (15). This was also true in patients with PTSD whether or not they were on concurrent antidepressants.
Individuals with PTSD were also noted to be at an increased risk for sleep-disordered breathing, specifically obstructive sleep apnea. One study suggested that around 40% to 90% of individuals with PTSD also suffered from obstructive sleep apnea (27). When screening for obstructive sleep apnea, these individuals often do not report excessive daytime sleepiness due to their hyperarousal/hypervigilance state, thus masking the daytime symptoms normally seen with obstructive sleep apnea. A thorough history and contributory information for a bed partner is crucial until a formal polysomnogram can be performed. Around one third of individuals with PTSD were also diagnosed with periodic limb movement disorder (PLMD), which led to increased arousals and awakenings (27).
Polysomnography data. Polysomnography in individuals with anxiety and trauma based disorders tend to be consistent with subjective complaints of poor sleep.
A 2018 study looking at time of day effects on sleep and anxiety showed that decreased total sleep time relative to personal average total sleep time predicts subsequent anxiety (11). It has also been reported that individuals with GAD had increased sleep onset latency (SOL) and increased wake after sleep onset (WASO) and reduced sleep efficiency (37). This result is consistent with previous studies looking at adolescents with GAD where they found decreased total sleep time and increased morning anxiety (30). For PTSD, studies have had inconsistent results on effects of total sleep time and severity of PTSD symptoms (11). Studies have shown that individuals with PTSD had more stage N1 sleep and REM sleep, but had less slow-wave-sleep (stage N3) as compared to healthy controls (37). These studies also found consistent sleep fragmentation with individuals with PTSD.
Diagnosis of sleep disorders in patients with anxiety. Individuals with anxiety disorders whose sleep disturbances are severe may qualify for a comorbid sleep disorder diagnosis. The primary diagnosis seen in these individuals is insomnia disorder. Prior to the DSM-5, “insomnia due to mental disorder” was used for diagnosis; however, the DSM-5 replaced this with “insomnia disorder” (02). The DSM-5-TR differentiates between episodic (symptoms lasting 1 to 3 months), persistent (symptoms lasting longer than 3 months), and recurrent insomnia (two or more episodes within the space of 1 year).
Specific criteria for the diagnosis of insomnia disorder per the DSM-5 TR includes:
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1. A predominant complaint of dissatisfaction with sleep quality or quantity associated with at least one of the following: |
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a. difficulty initiating sleep b. difficulty maintaining sleep c. early morning waking |
2. Sleep disturbance causes significant distress or impairment in daily life and function 3. Occurs at least 2 nights per week 4. Present for at least 3 months 5. Occurs despite adequate opportunity for sleep 6. Not better explained by and does not occur with another sleep-wake disorder 7. Not attributable to the physiological effects of a substance 8. Coexisting mental disorders and medical conditions do not explain the insomnia |
The text revision of the third edition of the International Classification of Sleep Disorders (ICSD-3-TR) defines insomnia disorder as a persistent difficulty with sleep initiation or maintenance that is associated with concern, dissatisfaction, or perceived daytime impairment, such as fatigue, poor mood, irritability, or cognitive changes (01). The ICSD-3-TR differentiates between short-term insomnia, chronic insomnia, and other insomnia disorder. Changes were made to the criteria for chronic insomnia in this new text revision. The ICSD-3 criteria included that a sleep/wake difficulty is not better explained by another sleep disorder. The text revision clarifies this criteria by stating that the sleep disturbance and daytime symptoms are not due to another sleep disorder, medical condition, mental disorder, or medication/substance use.
All of the following criteria must be met for the diagnosis of short-term insomnia disorder per the ICSD-3-TR:
1. Patient reports (or caregiver or parent observes) one or more of the following: |
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a. difficult to initiate sleep b. difficult to maintain sleep c. early morning awakenings d. resistance to appropriately scheduled bedtime e. difficult to sleep without parent or caregiver intervention |
2. Patient reports (or caregiver or parent observes) one or more of the following related to night time sleep difficulty: |
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a. fatigue/malaise b. impaired attention, memory, or concentration c. impaired social, job, family, or academic performance d. mood disturbance/irritable e. subjective daytime sleepiness f. behavioral problems g. decreased motivation/energy h. increase in accidents/errors i. dissatisfied with sleep |
3. Sleep/wake complaints cannot be explained only by inadequate time/opportunity or circumstances to sleep |
4. Symptoms present for less than 3 months |
5. Not solely due to another sleep disorder, medical disorder, mental disorder, or medication/substance use |
The diagnostic criteria for chronic insomnia are the same as for short-term insomnia, with the only difference being that the symptoms last for at least 3 months. The diagnosis for other insomnia disorder is only used for individuals who have difficulty initiating and maintaining sleep and do not meet the full criteria for chronic or short-term insomnia disorder.
Prognosis and complications
For many patients with an underlying anxiety disorder, the sleep symptoms may wax and wane, many times preceding and lingering after the mood symptoms. Based on the ICSD-3-TR, the prognosis of insomnia disorder can either be episodic or persistent. The type of sleep complaint (sleep initiation insomnia vs. sleep maintenance insomnia) can also change over time. Short-term insomnia that is caused by a clear inciting event may stop once the trigger has been eliminated. Chronic insomnia, however, can also have an intermittent course, with recurrent episodes that worsen with various life stresses. Complications of persistent insomnia disorder include increased risks for new onset or recurrent depressive and other psychiatric disorders, as well as suicidality. Chronic insomnia also leads to increased risks at work and leads to long-term use of over-the-counter sleep aids. There has also been an increased risk of hypertension in individuals with short objective sleep duration (less than 6 hours).
Individuals with generalized anxiety disorder tend to report that they have felt anxious and nervous for their entire life. The symptoms tend to be chronic, but waxing and waning throughout life. Symptoms appear to be more persistent in low-income countries, but impairment tends to be higher in high-income countries. Rates of full remission are also very low. Children and adolescents with anxiety disorders tend to worry about their performance at school or in sports or other activities. They also tend to worry more about catastrophic events like natural disasters or war.
The course of panic disorder is variable, with 30% to 40% of patients being symptom free, and 10% to 20% continuing to have significant symptoms at long-term follow-up. Good premorbid occupational and social functioning and the presence of a clear precipitating event are good prognostic features.
According to the DSM-5-TR, PTSD can occur at any age, and there is abundant evidence for “delayed expression” of symptoms. The duration and predominance of different symptoms tend to vary over time. Complete recovery can occur within 3 months in around half of adults diagnosed with PTSD, whereas others remain symptomatic for over a year, sometimes for several decades. Symptom recurrence and intensification can occur in response to triggers and life stressors.
Clinical vignette
A 35-year-old woman is referred to the sleep clinic by her psychiatrist with complaints of poor sleep. She has a diagnosis of posttraumatic stress disorder (PTSD) and anxiety disorder and reports a history of difficulty falling and staying asleep ever since a traumatic event 6 years ago. The patient reports that an intruder had broken into her house at night while she was asleep at that time. She describes that, at first, she would be anxious when going to bed and it would take a long time for her to calm herself and then fall asleep. She would also wake frequently at night fearful with a racing heart rate and feelings of impending doom. In addition, she reports frequent nightmares of being chased by an ominous figure. Her difficulties were so frequent and distressing that she started to worry about sleeping in the daytime and actively tried to avoid going to bed. She was seen by psychiatry and was diagnosed with PTSD and panic attacks. She was started on sertraline with improvement in the panic attacks and her other PTSD symptoms, however she continued to have the nightmares and difficulty sleeping. She tried several hypnotics, prior to being seen in the sleep clinic, including trazodone, zolpidem, eszopiclone, and mirtazapine. All these medications helped for a period, but all stopped working past 6 months. She was diagnosed with chronic sleep onset and maintenance insomnia as well as nightmare disorder. She was given several sessions of cognitive behavioral therapy for insomnia as well as low dose gabapentin to help with sleep maintenance and residual anxiety. Treatment of the nightmares consisted of image rehearsal therapy. At her third follow-up appointment 6 months later she reported reduced nighttime awakenings and a reduction in the frequency of her recurrent nightmares. At her 1-year follow up she reported reduction of sleep onset latency to 30 minutes or less most nights and no further nightmares. (In this vignette any resemblance to any persons, real or imagined, is purely coincidental.)