Types of Sleep Disorders

Insufficient sleep syndrome

The insufficient sleep syndrome is a disorder that occurs in an individual who fails to obtain sufficient nocturnal sleep to support normally alert wakefulness.⁸ The individual is in fact chronically sleep-deprived at his own will, without being aware of it. Such a situation is increasing in our modern technologically inclined societies. The individual is pressured by socio professional imperatives and feels that he or she does not have the time to do everything. The worker may also be doing shift work. As the nights pass by, sleep debt increases. The insufficient sleep syndrome causes 5% to 10% of consultations for excessive daytime sleepiness.²⁷

The subject is generally an active or overactive 40-year-old man, with responsibilities and a high social status. The syndrome can also be related to shift work or frequent trans meridian airplane trips.

As the sleep debt develops, the individual starts suffering from excessive somnolence in the afternoon, in the evening, or after meals. Patients report that they sleep 5 to 6 h nightly on weekdays, and 9 h during the weekends. They have difficulty rising in the morning and sometimes experience sleep drunkenness-like episodes. Work and cognitive performance, as well as decision-making, may be impaired. The patient may also complain of increasing levels of subjective fatigue, mood deterioration, muscular pain, gastrointestinal upset, and visual disturbances. Symptoms disappear on weekends and during the holidays.

The diagnosis is mainly performed during interview. However, in cases of a suspected associated pathology, such as respiratory disturbances during sleep, a polysomnographic recording may be indicated. In the case of insufficient sleep syndrome, this recording will show a good sleep efficiency (>90%) and short sleep latency, indicative of a sleep rebound

Insomnia

 Insomnia is considered to be the most common sleep disorder. Its prevalence varies considerably based on the definition used. While one-fourth to one-third of the general population reports a complaint of difficulty falling and / or staying asleep [1–9], about 10% present chronic complaints and seek medical help for insomnia. [10, 11] However, insomnia has always been and still is an under-recognized and therefore under-treated problem, since about 60% of the people suffering from insomnia never talk to their physicians about their sleeping difficulties. [12–13] The inadequate identification and treatment of insomnia has significant medical and public health implications. Chronic insomnia results to impaired occupational performance and affects quality of life. [14–15]

Insomnia, is defined as the complaint of difficulty initiating or maintaining sleep, early awakening, and interrupted or non-restorative sleep. Additionally, nighttime symptoms are accompanied by clinically significant impairment in daytime function, for which no identifiable cause i.e. other sleep disorder, psychiatric disorder, medical condition, is attributed. [16] The significance of insomnia is determined by its severity, frequency, duration and the daytime function impairment.[17–18] A presentation of insomnia for three or more times weekly is evaluated as clinically significant. Furthermore, the duration of a month or less is called transient insomnia and is frequently triggered by external stressors. Transient insomnia would usually be self-resolved after the person is adjusted to the stressful event or the events are resolved. Symptoms that last between one and six months are classified as sub-acute insomnia, whereas if they persist for more than six months, then they are classified as chronic insomnia. [16] There  is no objective way to measure impairment of daytime functioning, it and only subjective reports can indicate its significance.

Insomnia occurs more frequently in women, both in terms of symptoms reported and of daytime consequences.[19] Menopause has been proposed as an explanation for this difference among mid-aged men and women but other underlying chronic conditions, e.g. increased prevalence of depression in women, seem to be also significant. Aging is another significant factor associated with increased prevalence of insomnia, present in up to 50% of people over 65 years old. In terms of socioeconomic status, insomnia is more frequent among individuals who are separated, divorced or widowed, especially in women, or have a lower educational / economical status or are unemployed. [19]

Stressful life events are closely associated with the onset of chronic insomnia and are mediated by certain predisposing personality factors. Insomniacs compared to controls, tend to be more discontent, both as children and as adults, have less satisfying interpersonal relations, and relatively poor self concepts, leading to inadequate coping mechanisms for dealing with stress.[

“Sleepiness” and “Fatigue

The terms of “sleepiness” and “fatigue” have been used interchangeably both by patients and physicians. However the Insomniacs’ frequent complaints of daytime fatigue. Sleepiness is a subjective feeling of physical and mental tiredness associated with increased sleep propensity. Fatigue, on the other hand, is also a subjective feeling of physical and/or mental tiredness; not associated with increased sleep propensity.

An easy way to differentiate these two symptoms is by asking the patient how likely it is for him/ her to fall asleep during the day, if given the opportunity. While for insomniacs, who frequently complain of fatigue, it is rather unlikely to nap, patients with disorders of excessive daytime sleepiness, such as narcolepsy or sleep apnea, are very likely to fall asleep during the day, especially if circumstances allow.

“Sleep deprivation” vs “Insomnia”

It has been shown that insomniacs compared to normal sleepers have significantly increased rectal temperature, heart rate, vasoconstriction, and increased skeletal muscles movements before and during sleep. [30,43,44]On the contrary, in sleep deprivation, findings regarding physiological activation are inconsistent. While some studies report increased body temperature, others show minimal changes or even decrease of the temperature after sleep restriction.[45] Similarly, heart rate following sleep deprivation in some studies is reported as decreased, whereas in others it does not change. [46–47]
Physiological studies have also shown insomniacs to have different response to the release proinflammatory cytokines at HPA axis than sleep deprived and normal sleepers.

Insomnia can be classified in different ways.
Acute vs. Chronic Insomnia

Insomnia can be classified by the amount of time the problem affects your life. It can be described as acute (short term) or chronic (long term). It can also occur for a period, stop, and then recur.

Acute insomnia involves problems falling asleep or staying asleep at least three days per week for a period of between one week and three months. It is usually linked to one of the following factors:²³

• Stress at home and/or work
• Stress in personal or professional relationships
• Physical injury
• Environmental changes caused by light, noise, or temperature
• Acute pain
• A traumatic event such as the loss of a loved one, divorce, or job loss
• Jet lag
• Temporary use or withdrawal of caffeine, alcohol, illegal drugs, or prescribed medications
• Shift work

Chronic insomnia involves being unable to fall asleep or stay asleep at least three days per week for a period of three months or longer.⁴ It may result when the stressors that cause acute insomnia aren’t handled.

Chronic insomnia can also occur as a symptom or side effect of one of the following conditions:⁵⁶

• Chronic medical conditions like GERD (gastroesophageal reflux disease), heart disease, or thyroid problems
• Other sleep disorders like sleep apnea or restless legs syndrome (RLS)
• Chronic mental health problems like depression, anxiety, or PTSD (post-traumatic stress disorder)
• Long-term use of certain medications or illegal drugs
• Long-term use of caffeine or alcohol
• Lack of regular sleep habits

Primary vs. Secondary Insomnia

Insomnia can also be classified based on the condition’s relationship to other issues.

Primary insomnia occurs when your inability to sleep isn’t linked to a known cause. The fact that you can’t sleep and/or remain asleep isn’t due to a side effect of a medical condition, psychological issue, or medication.

Primary insomnia may occur due to unknown causes, though it can be linked to the effects of the following issues:²

• Long-lasting stress
• Emotional distress
• Travel or jet lag
• Shift work

Secondary insomnia accounts for most cases of insomnia. It can be acute or chronic. Secondary insomnia occurs as a side effect or symptom of one of the following factors:²

• Medical conditions
• Psychological conditions
• Sleep disorders
• Substances like caffeine, alcohol, or tobacco
• Prescription medications or illegal drugs

Onset vs. Maintenance Insomnia

Insomnia can be defined based on where it interferes with the natural sleep cycle. It can prevent you from falling asleep and staying asleep.

Onset insomnia affects your ability to fall asleep at the time you wish. It is usually linked with psychological or psychiatric issues. Onset insomnia can also be a symptom secondary to a medical condition or sleep disorder.

Onset insomnia is more common in younger than older adults.⁷

 It can also occur when children become stressed by being alone before sleep.

People who have onset insomnia often have one of the following conditions, though others are possible:⁸

• Psychophysiological insomnia (PPI)
• Obstructive sleep apnea-hypopnea syndrome
• Periodic limb movements in sleep (PLMS)
• Delayed sleep phase syndrome
• Congestive heart failure
• Restless legs syndrome

Maintenance insomnia is a condition that makes it difficult to maintain sleep after you’ve fallen asleep. It occurs more often in older adults since sleep cycles change with age.

Diagnosis

Insomnia is a difficult disorder to treat and the importance of a multidimensional evaluation that includes thorough sleep history, medical history, physical examination and drugs / substances use, as well as psychiatric assessment has been stressed for many years, although frequently overlooked in daily practice. [20]

Sleep laboratory testing is not necessary in the evaluation and diagnosis of most insomniacs and that sleep laboratory measurements are of limited value in distinguishing insomniacs from normal sleepers. Indeed, the use of the sleep laboratory to predict severity of chronic insomnia is costly and impractical, given that other simpler methods, such as actigraphy, may provide information that is just as useful to the practicing physician.[31]