Sleep disorders are a common problem in the modern world, full of stressful situations, round-the-clock work, a large number of temptations and excesses, combined with a sedentary lifestyle of people and poor ecology.

The physiological significance of sleep is the rest of the body, the strengthening of motor functions, memory, and the consolidation of skills. Sleep disturbances cause fatigue, weakness, excitability, inhibition of motor functions, impaired ability to concentrate. Modern science has convincingly shown that sleep is an active, complex, multifunctional process. The study of sleep in normal conditions and in various sleep disorders has led to the emergence of a new branch of medicine – sleep medicine or, as it is also called, somnology – the science of sleep.

Currently, 8 to 15% of the world’s adults complain of frequent or persistent complaints of poor or insufficient sleep, 9 to 11% of adults use sedative-hypnotic drugs, and this percentage is much higher among the elderly. In accordance with the International Classification of Diseases, sleep disorders are classified as follows: sleep disorders and sleep duration ( insomnia ), excessive sleep duration ( hypersomnia ), sleep-wake cycle disorders, sleep apnea, narcolepsy and cataplexy, and other sleep disorders.

Sleep disorders can develop at any age. Some of them are more common in certain age groups, such as bedwetting, night terrors and somnambulism in children and adolescents, and insomnia or pathological sleepiness in middle-aged and older people. Other disorders, such as narcolepsy-cataplexy syndrome, may begin in childhood and persist throughout life.

The most common sleep disorder is insomnia. Each of us knows what sleep deprivation is. This is lethargy and drowsiness throughout the day, bad mood, inability to concentrate on important matters. Normally, the human body itself compensates for the lack of night sleep, lengthening it the next night. And if you do not get enough sleep systematically, how does this happen with insomnia? This sleep disorder combines various conditions. It means the inability to sleep, despite the fact that circumstances allow it, it is a violation of the sensation of the duration of sleep, a change in the depth of sleep, a violation of the sensation of rest. Sleep superficial, fragile, with frequent repeated awakenings during the night. There may also be difficulty falling asleep, sleep may not come at all. With insomnia, there may be opposite sleep disturbances – waking up too early, the inability to fall asleep again. Often there is a combination of these symptoms. Insomnia significantly reduces the quality of life of a person and affects his performance, which determines the medical and social significance of this problem. A person suffering from this sleep disorder is drowsy during the day, it is difficult for him to concentrate on daily work, and his productivity decreases. Over time, psychological distress develops – fatigue, nervousness. Nervous processes, having lost their usual strength and weakened, linger for a long period in certain parts of the brain, forming foci of inhibition or stagnant excitation, over time, excitatory processes begin to predominate over inhibitory ones. If a person turned to a specialist in sleep disorders in time – in the early stages of the disease, it is not difficult to help him. However, patients often come to the doctor with insomnia that lasts for years and is complicated not only by functional disorders of the nervous system, but also by diseases of the digestive, cardiovascular and respiratory systems. According to the University of Chicago Medical Center’s 1999 Sleep Disorders Study, chronic sleep deprivation and insomnia significantly interfere with the body’s ability to metabolize glucose, which can lead to early-stage diabetes symptoms.

Hypersomnia is a sleep disorder that refers to the presence of excessive sleep duration. Hypersomnia is characterized by recurring episodes of excessive daytime sleepiness or excessive nighttime sleep. It is necessary to distinguish between psychophysiological hypersomnia observed in practically healthy individuals with insufficient night sleep or under stress, and various pathological variants of hypersomnia – narcolepsy, idiopathic hypersomnia , various sleep disorders associated with breathing (sleep apnea syndrome, movement disorders in sleep), neurotic disorders, post-traumatic hypersomnia , drug-induced hypersomnia , circadian rhythm disturbance, etc.

The most clinically significant hypersomnia is a sleep disorder such as narcolepsy, characterized by excessive daytime sleepiness with imperative (irresistible) episodes of daytime sleep; restless night sleep and a feeling of lack of sleep ; hallucinations when falling asleep or waking up; cataplexy (sudden loss of muscle tone, usually occurring against the background of strong emotional experiences); awakening cataplexy. With this sleep disorder, there is an early onset of the REM phase (immediately after falling asleep or during the first minutes of sleep), a decrease in the severity of delta sleep and the appearance of frequent episodes of wakefulness during nocturnal sleep. Narcolepsy is a lifelong disease and its treatment is symptomatic.

Violations of sleep and wakefulness, non-compliance with sleep hygiene also lead to sleep disorders. Everyone knows that in the evening it is better to refrain from drinking caffeine-containing drinks and alcohol, it is advisable not to smoke at least 2 hours before bedtime. Medications can also interfere with the body’s biorhythms and lead to insomnia, fatigue, restlessness, and agitation. There are two categories of disorders of the circadian cycle of sleep and wakefulness: transient and permanent. Transient sleep disturbances due to rapid change in standard time (“reactive phase shift”) have long been known, as well as similar conditions observed with a sharp change in work schedule. The sleep disturbances that result from this are due to both sleep deprivation and changes in the pattern of circadian rhythms. This condition is characterized by short sleep with frequent awakenings and daytime sleepiness. Restoring synchronization takes from several days to 2 weeks .

Parasomnias are sleep disturbances when, against the background of the entire sleep process and its individual stages, many unpleasant behavioral and physiological phenomena can occur. In sleepwalking (somnambulism) , people suddenly sit up in bed, walk, or perform automatic semi- purposeful complex movements. Patients with similar sleep disorders are unconscious and resist awakening. Sometimes they take actions that threaten their health, such as trying to climb out the window. The attack usually lasts less than 15 minutes and ends with the patient returning to bed or waking up (without a story about dreams). Sleepwalking occurs during stages III and IV of non-REM sleep. In the diagnosis of this sleep disorder, it is important to exclude signs of convulsive readiness from a nocturnal epileptic seizure that occurs when the temporal lobes are affected. Somnambulism occurs in children and adolescents: 15% of them noted one or more such episodes of sleep disturbance. In a small number of children (from 1 to 6%), seizures at night can be repeated frequently. The presence of seizures and their persistence during puberty may be a psychopathological sign.

Bruxism is another sleep disorder that begins in childhood. These are paroxysmal contractions of the masticatory muscles that periodically occur in a dream, accompanied by clenching of the jaws and gnashing of teeth. According to various sources, bruxism is more or less constantly observed in 1-3% of people. To date, the exact causes of the development of this sleep disorder have not been established. Bruxism is often observed in patients with defects in the structure of the facial skeleton, malocclusion and pathology of the joints connecting the lower jaw to the temporal bone. It is also suggested that bruxism is associated with motor or neurological disorders such as orofascial dyskinesia, mandibular dystonia, or tremor. If this sleep disorder persists in an adult, then, firstly, it is necessary, if possible, to eliminate all existing dental problems or bite defects, and, secondly, to consider the advisability of using intraoral protective applicators made of rubber or soft plastic, which are fixed between the teeth and prevent their injury.

Other sleep disorders characterized by the onset of functional disorders are head bobbing , painful erections, migraine -like headaches, gastroesophageal reflux, paroxysmal nocturnal hemoglobinuria, and sleep paralysis due to peripheral nerve compression.

Sleep disturbances are stressful for the whole body. They lead to a decrease in mental activity and other mental defects. Lack of rest leads to a deterioration in mental abilities – the ability to think, respond to stress and critical situations, and maintain a healthy immune system. Experiments proved that laboratory rats died within a few weeks with artificial sleep disturbance and lack of necessary rest. Sleepiness leads to increased levels of stress and anxiety. Stress and anxiety, in turn, can lead to insomnia. In the absence of timely medical attention, this vicious circle can lead to the development of anxiety disorders and depression in the background of sleep disorders. Irritability, temper tantrums, emotional outbursts, and even violence are not uncommon among those who are chronically sleep deprived as they lose control of their emotions. Many children with sleep disorders develop Attention Deficit Hyperactivity Disorder (ADHD). Although the symptoms of insomnia and ADHD are similar (irritability, inability to concentrate and control nerve impulses), a sharp deterioration in ADHD symptoms indicates a nervous breakdown caused by sleep disorders. Due to insufficient rest and lack of normal sleep, we cannot focus our vision. It also makes it difficult to perform small motor functions. Muscle strength and endurance are sharply reduced, which is explained by low glucose metabolism . Sleep disturbance, in particular its lack, increases appetite, which leads to weight gain. There is a direct relationship between normal rest and the functioning of the immune system. Sleep disturbances increase the body’s susceptibility to infections because it lowers blood levels of some important immune cells and cytokines (an important protein for health).