Sleep is defined by WHO as a recurring natural state of unconsciousness (but without loss of sensory reception) of the outside world, accompanied by a gradual decrease in muscle tone, occurring at regular intervals. Sleep-wake alternation is one of the fundamental cycles in animals: the circadian rhythm. In humans, sleep occupies about one third of life on average. It is recognized as soothing, precious and important. We often talk about the restorative effect of sleep.
It is common to feel tired or to find that your sleep has not been restorative. Sometimes this sensation is transitory and the following night puts us back on the road. But when it’s regular, it may be wise to look for one or more sleep disorders.
These disturbances of sleep can be of several orders and have and causes and very varied consequences.
According to the DSM-IV, which corresponds to the International Statistical Classification of Diseases and Health Conditions code, primary sleep disorders are classified as dyssomnias and parasomnias.
- The purpose of this article is to enumerate these different disorders, as well as to identify how these interfere with normal sleep.
What are the main sleep disorders?
Sleep disorders can be classified into three major groups:
- Dyssomnias: these are disorders that alter the duration or quality of sleep. They include insomnia and its various types and origins, as well as hypersomnia.
- Parasomnias: these are unusual behaviors experienced during sleep without really impacting alertness in the waking period. There is nocturnal bruxism, sleepwalking or sleep apnea.
- Other sleep disorders that may be of neurological origin (migraine, Parkinson’s disease …), psychiatric (manic depression, depression …), or secondary to certain pathologies (gastroesophageal reflux, severe asthma..).
We talk about insomnia either when we have difficulty falling asleep at bedtime (initial insomnia), either when we have frequent or prolonged nocturnal awakenings, or finally when we wake up prematurely in the morning with an inability to sleep again. A person may suffer from a mixture of these symptoms, or may change with time symptoms.
Insomnia is the sleep disorder most commonly encountered in sleep medicine. It is estimated that about 20% of the general population would suffer from chronic insomnia and 30% from occasional insomnia
Taking more than 30 minutes to fall asleep, with sleep duration of less than 6 hours 30 a night is a problem of insomnia. It should be noted that if you sleep 6 or 7 hours a night and feel rested the next day, you do not suffer from insomnia.
According to the chronology of its evolution, one can suffer from transitional insomnia (problems of life, worries), in the medium term, or in the long term: insomnia becomes chronic.
- There are several types of insomnia:
- Acute insomnia:
Acute insomnia of adjustment is that which is caused by a difficult event or a stressor (mourning, loss of employment, distress of all types). This type of insomnia lasts a few days and disappears in less than three months. Generally, this problem quickly resolves itself to the disappearance of the trauma or the factors involved. In the most vulnerable people, insomnia may persist and become chronic.
- Psycho-physiological insomnia :
This type corresponds to the idea that the person suffers so much from not sleeping that she ends up being afraid to go to bed and not to fall asleep, constituting a real vicious circle. This generates a negative conditioning between going to bed and the anxiety of not falling asleep. Anxieties for sleep performance appear (fear of failing to fall asleep or getting enough sleep), with an inability to fall asleep at a scheduled time. Paradoxically, sleep is much easier outside the home. Cognitive and behavioral treatments offer good results.
- Bad perception of sleep:
This is a “true-false” insomnia. The person is convinced that she is suffering from insomnia. Her real feeling is that she only sleeps a few hours during the night or not at all. It is not simulation: simply these people have a poor ability to assess the quality and quantity of their sleep. However, polysomnographic examinations show that these people sleep is good enough.
- Idiopathic insomnia:
This condition is rare and is characterized by a constant inability to get an adequate amount of sleep. In contrast to psycho-physiological insomnia, this insomnia remains stable and is not influenced by stress. It occurs in childhood, and studies suggest that it is caused by an abnormal neurological control of the sleep-wake system.
- Insomnia related to a mental disorder:
Many mental illnesses can induce sleep disorders. Nevrosis, just like psychosis can cause insomnia. Depression is often characterized by early morning insomnia, while manic access in bipolar disorder is characterized by insomnia of falling asleep. Schizophrenia is also linked to an increased risk of insomnia.
- Poor sleep hygiene:
Insomnia can be caused by poor sleep hygiene. Either the person will have activities that will encourage vigilance and thus alter the architecture of sleep (extreme physical exercises before bedtime, watch a horror movie, online games etc.). Either the person does not offer behaviors and an environment that promotes sleep (poorly ventilated room, too hot, disturbing pets, etc.).
- Behavioral insomnia of the child :
Children can paradoxically “learn” to sleep poorly. Sleep habits are instilled by parents by how they propose to the child when and how to sleep. Inadequate responses given to their child at bedtime or when the child does not want to sleep can lead to behavioral insomnia. Solutions exist to deal with this problem. (Behavioral therapies)
- Insomnia due to a drug or substance
Although alcohol is the most widely used “sleeping aid” on the planet, it unfortunately offers a poor quality of sleep to the abuser (non-recuperative sleep and poor quality). Other substances can cause insomnia, such as medical pills (because of their side effects) or drugs (often excitants). Sleeping pills taken too much or too long can lead to insomnia (we call this a “rebound insomnia”: as soon as the person wants to stop taking sleeping pills, insomnia returns stronger, which pushes the person to take them back again).
- Insomnia related to a medical condition
Many medical conditions and illnesses have symptoms that can be exacerbated at night, and thus lead to insomnia like Asthma, gastroesophageal reflux, hyperthyroidism, etc. It is by treating the initial medical condition that one can relieve the person from the insomnia.
It’s important to not confuse hypersomnia which may be excessive drowsiness or falling asleep under abnormal conditions and drowsiness due to temporary fatigue or other disorder.
Narcolepsy is one of the hypersomniac disorders: It is characterized by bouts of irrepressible daytime sleepiness. It may or may not be associated with cataplexy (sudden loss of muscle tone without loss of consciousness following a strong emotion, most often positive).
- Parasomnias: Parasomnias are most often seen in children but can occur at any age with sometimes impressive consequences. These are the different types of parasomnias:
- The syndrome of periodic movements of the legs during sleep: These periodic movements are involuntary and repeated movements of the limbs. They are classified into 2 syndromes, the “Muscular impatience syndrome of awakening” and the “Syndrome of periodic movements of the limbs during sleep”.
- Bruxism: (from the Greek brugmos “grinding of the teeth”) is a mandibular parafunction (unconscious movement without a precise goal concerning the masticatory apparatus) either by tightening or lateral movements, often occurring during sleep.
- Somnambulism: (the Latin word meaning “to walk in sleep”) is a sleep disorder belonging to the family of parasomnias. Sleepwalkers experience nocturnal, unconscious ambulation during sleep. These movements can be safe like sitting on the bed, walking in the bathroom or cleaning objects, or sometimes hazardous like cooking, driving etc.
- Sleep apnea: Sleep apnea is a suspension of more than 10 seconds of the respiratory flow during sleep. Sleep apnea may be obstructive and may result in a decrease of respiratory control in the nervous system.
- To conclude, sleep disorders correspond to a wide spectrum of dysfunctions concerning the normal circadian rhythm of individuals. Their treatment is thus essential because of the many repercussions of these disorders on health.