Insomnia: Clinical Features PDF

# Chapter 1 - Clinical features of insomnia ## Definition Insomnia refers to a difficulty in initiating or maintaining sleep at least three nights per week for at least three months, accompanied by impaired daytime functioning. Clinicians and researchers also expect to find greater than 30 minutes...

# Chapter 1 - Clinical features of insomnia ## Definition Insomnia refers to a difficulty in initiating or maintaining sleep at least three nights per week for at least three months, accompanied by impaired daytime functioning. Clinicians and researchers also expect to find greater than 30 minutes of sleep onset latency or wake time after sleep onset on poor sleep nights. Chronic, clinically significant insomnia is found in 10% of the population, making it one of the most common psychiatric disorders. It is most often precipitated by stress or a mental disorder but usually evolves into an independent, self-sustaining problem untethered from the original causal agent. ## Typical insomnia symptoms | Symptom | Characterization | |------------------------------------|-------------------| | Insomnia identity | Patient believes they have a sleep disorder. Non-complaining poor sleepers (ie, individuals accepting of less than ideal sleep), would not be diagnosed with insomnia. | | Difficulty initiating or maintaining sleep | Patient reports it frequently takes more than 30 minutes to fall asleep or awakenings during the night accumulate to more than 30 minutes. | | Associated impaired daytime functioning | Paient believes degraded functioning, such as mood disturbance, fatigue, and cognitive impairment, are a by-product of poor sleep. Worry about sleep, during the day and at night, is a common feature of insomnia. | **Table 1.1 Typical insomnia symptoms. Adapted from American Psychiatric Association** ## Risk factors Insomnia may occur in any stratum of the population but it is most common in women and older adults. Additionally, patients with anxious and worry-prone personality types, increased arousal predisposition, and emotional suppression may be more susceptible. Environment plays a role, as noise, light, intemperate and uncomfortable surroundings can contribute. Genetics may also act as a risk factor, as insomnia has been shown to have a familial component and higher rates are found in monozygotic twins relative to non-identical twins. ## Clinical presentation and symptoms of insomnia Patients with insomnia often do not broach the subject of sleep with their physician unless specifically asked. Those who do present with insomnia will often state that “I just can't sleep." An important aspect of insomnia presentation that needs to be assessed is the portions of the night that are affected by sleeplessness. As such, a difficulty with falling asleep is considered *sleep-onset insomnia*; waking up in the middle of the night and having difficulty returning back to sleep is considered *sleep maintenance insomnia*; and waking up early in the morning (ie, earlier than desired) and not being able to return to sleep is considered *terminal insomnia* or *early morning awakenings*. These different patterns of insomnia can be helpful for the differential diagnosis of insomnia. However, in the majority of cases, patients report that their insomnia affects more than one portion of the night. Over time, an individual's pattern of insomnia can also change. Patients will often present with the daytime complaint of tiredness or fatigue but often do not report being sleepy during the day and it is felt that this is a further manifestation of hyperarousal underlying their insomnia. There are individuals who have difficulty falling asleep or staying asleep at night, but who do not feel that it has any impact on them during the day, and thus will not mention their sleep patterns to their health care providers. Those who seek treatment usually do so because of the perceived negative consequences their insomnia is producing, including cognitive difficulties such as problems with memory, concentration, or decision making. Other presenting daytime complaints include irritability, low energy, and low mood. ## Classification Comprehensive sleep assessment was first introduced in the *Diagnostic and Statistical Manual of Mental Disorders (DSM)* by the American Psychiatric Association, and was followed shortly by the first *International Classification of Sleep Disorders (ICSD)* produced by the American Sleep Disorders Association. The most recent revisions of both of these manuals, the fifth edition of the DSM (DSM-5), and the third version of the ICSD (ICSD-3), were coordinated to coincide and reflect better classification uniformity than had been achieved by these two systems in the past. Previously, differences between the two systems caused diagnostic confusion in both the clinical and research realms but now the ICSD and DSM-5 criteria closely correspond. In the DSM-5, clinically significant insomnia is called *insomnia disorder* and its diagnostic criteria are given in **Table 1.2**. The criteria require both a complaint of poor sleep and associated daytime impairment, and better accommodate children and dependent older adults than the previous edition. Thus, poor sleep unaccompanied by poor functioning would not qualify as *insomnia disorder*. The truncated condition might simply be called 'poor sleep' with the patient having symptoms of insomnia. Reserving the formal diagnostic label for those individuals who exhibit the full insomnia syndrome is consistent with consensus insomnia assessment recommendations. The sleep disturbance must occur on average at least three times per week for at least 3 months. The criteria rule out individuals whose poor sleep is attributed to inadequate opportunity due to factors such as demanding work obligations or a disruptive lifestyle. The ICSD-3 uses the term *chronic insomnia disorder* (**Table 1.3**). Like the DSM-5, the ICSD-3 criteria also require both a complaint of poor sleep and associated daytime impairment and accommodate children and dependent older adults. The ICSD-3 adopted the same frequency, duration, and opportunity standards as the DSM-5. The ICSD-3 added a qualifier to account for instances when insomnia is an epiphenomenon of another sleep disorder. For example, if it is determined that the insomnia symptoms do not represent an independent disorder but rather are secondary to obstructive sleep apnea or narcolepsy, this would rule out a chronic insomnia disorder diagnosis. ## Changes in diagnostic criteria Insomnia characteristics in the previous version of the DSM (DSM-IV-TR) that have been eliminated in the 2013 version include: - diagnosis of insomnia related to another mental disorder - sleep disorder due to a general medical condition - substance-induced sleep disorder (ie, ‘secondary insomnias') The DSM-5 has added frequency, extended duration, and opportunity criteria. Additionally, the previous version of the ICSD (ICSD-2) specified 11 distinct insomnia diagnoses including: adjustment insomnia, paradoxical insomnia, and inadequate sleep hygiene. However, poor reliability in differential diagnosis justified replacing all of these by the single category: chronic insomnia disorder. The ICSD-3 eliminated the non-restorative sleep criterion and added frequency and extended duration. ## Prognosis The experience of acute insomnia is typical during periods of life stress or other disruptions to health or routine. For most people, sleep improves once normal patterns are re-established, such as when the source of stress passes or health improves. For others, the insomnia persists and becomes chronic, even in situations in which the initial precipitating factors have passed. These individuals represent the 10% of the US population that suffer from chronic insomnia. There are 25 longitudinal studies conducted at the epidemiologic level that indicate that chronic insomnia, on average, tends to resolve in approximately 45% of cases. There are several caveats that need to be taken into consideration. First, these studies only assessed insomnia symptoms rather than determining whether clinically significant insomnia was present. This likely led to the inclusion of a number of people with only mild symptoms. In a study by Rosenthal et al that followed patients in a sleep clinic, much lower rates of remission were found. Second, as these studies did not assess insomnia treatment, it is not known whether some of these cases of improvement were due to individuals receiving treatment. Thus, there is a need for more research in this area, but, for now, it is generally thought that while insomnia may improve over time without intervention for some individuals, the majority would benefit from targeted treatment rather than a 'wait-and-see' approach.