Type of insomnia and clinical manifestations
Adaptive insomnia is the most common cause of sleep disturbances, occurring against a background of acute stress, conflict, or environmental change. As a result of this, an increase in the overall activity of the nervous system develops, which makes it difficult to enter sleep during evening falling asleep or nocturnal awakenings.
With this form, it is possible with great certainty to determine the cause that caused sleep disturbance. Adaptive insomnia lasts no more than 3 months. The average annual prevalence of adaptive insomnia among adults is estimated at 15-20%, however, such patients rarely go to the doctor, preferring to cope on their own.
The pathophysiological basis of adaptive insomnia is a hyperactivated state of the nervous system (hyperarousal) due to exposure to a stress factor. Both cognitive hyperactivation and an increase in sympathetic activity and the release of hormones of the hypothalamic-pituitary-adrenal axis play a role in the formation of this condition.
At the cognitive level, hyperactivation is supported by constant obsessive thoughts (ruminations) associated with a stress factor, which is accompanied by an increase in attention, wakefulness, and readiness to respond. With the onset of evening time, the intensity of rumination does not decrease, which leads to difficulties in falling asleep in the evening and during nocturnal awakenings.
In the future, against the background of developed sleep disorders, the key theme of ruminations may no longer be a stressor, but the inability to achieve normal sleep, while the fear of not falling asleep is formed. The presence of hyperactivation at the somatic level is confirmed by the results of a study of basal metabolism - in patients with insomnia, the amount of oxygen consumed increases compared to healthy people. Determination of the activity of the autonomic nervous system by analyzing the temporal characteristics of heart rate variability confirmed the presence of relative sympathicotonia in patients with insomnia during the entire 36-hour registration period.
The release of stress hormones during insomnia also increases. In patients, the level of daily excretion of free cortisol is increased, its concentration in the urine correlates with the time of night wakefulness. Excretion of catecholamines also correlates with bedtime and stage 1 non-REM sleep. When comparing the levels of cortisol and adrenocorticotropic hormone in blood plasma, it was shown that the maximum differences in these indicators in patients with insomnia and in well-sleeping people are observed in the evening and at night, which confirms the presence of hyperactivation that interferes with falling asleep and maintaining sleep at this level as well.
Psychophysiological insomnia is characterized by the presence of disturbances in the structure of sleep and a decrease in the effectiveness of daytime wakefulness due to the occurrence of somatized tension with the gradual formation of sleep-disturbing associations. The prevalence of this form of insomnia in the population is 1-2%, more often women are affected by it.
Most often, the development of psychophysiological insomnia occurs as follows. Initially, episodic insomnia develops as an adaptive type in response to emotional stress or a change in the usual sleep environment. Then the element of "conditioning" is turned on - the sleep disorder becomes self-sustaining. The patient in advance, before going to bed, begins to worry about whether he will fall asleep or not (the phenomenon of fear of a pillow), while the level of somatized tension and brain activation increases, and falling asleep is difficult. In the future, a stable association is established between the place or time of sleep and the increase in somatized tension. It is very characteristic that the patient in other, unusual conditions (even in the conditions of the sleep laboratory) sleeps much better.
The diagnosis of psychophysiological insomnia requires the exclusion of other possible causes of insomnia, primarily mental illness. Often these patients have high levels of anxiety and depression, the phenomenon of alexithymia, dysfunctional beliefs about the value of their sleep and the mandatory need to get exactly the right amount of it.
Most often, insomnia is associated with mental factors and therefore can be considered as a psychosomnic disorder. When making a diagnosis, it is important to determine the nature of insomnia - primary or secondary.
Idiopathic insomnia is a very rare form of insomnia, more often this diagnosis is made when it is impossible to establish the cause of sleep disorders that began in early childhood, without an obvious cause and significant periods of improvement present during the patient's life. The representation of this form of sleep disorders among patients with insomnia complaints is less than 10%.
Insomnia due to poor sleep hygiene
Usually develops in teenagers or the elderly. For the former, sleep disturbances occur against the background of excessive evening activity, which prevents falling asleep. The most common violations are playing on the computer before going to bed, watching exciting TV shows, and talking on the phone . As a result, the time to fall asleep is significantly increased, and in the morning there are difficulties with awakening.
In people of older age groups, the most common violation of sleep hygiene is daytime falling asleep, partially satisfying the daily need for sleep and “taking away” the corresponding time from night sleep. The prevalence of this form of insomnia is estimated at 1-2% among adolescents and young adults.
Pseudo-insomnia is a special form of insomnia. This is a disorder in which there are complaints of significant sleep disturbances that do not correspond to the objective picture of sleep and the degree of daytime dysfunction. Most often, patients say that they have not slept at all for decades.
However, despite complaints, they usually successfully continue to perform their production and social functions. The frequency of this form of insomnia in patients of sleep centers is 5%. For the diagnosis and successful treatment of this form, it is necessary to conduct a night polysomnographic study, which objectifies the picture of sleep. Usually, the value of the true indicators of night sleep differs from that presented to patients by 1.5 times.
Insomnia in diseases of the internal organs and the nervous system
Diseases such as arthritis, allergies, chronic heart failure, prostate adenoma cause sleep disorders. Physiological causes of sleep disturbance include hormonal changes, especially in postpartum and perimenopausal women. Evidence of the secondary nature of insomnia in these disorders is the occurrence of sleep disturbance after the development of the underlying disease or simultaneously with it, a change in the severity of sleep disturbances with fluctuations in the clinical picture of the disease.
In chronic cerebrovascular pathology, sleep disorders are usually complex in nature and are caused by the age of patients, changes in the environment, psychological state, the site of damage to the nervous system, the presence of comorbid disorders, and the drugs used.
Insomnia while taking medications and other drugs
Insomnia when taking drugs and other drugs (a form of drug dependence) is associated with long-term use of sleeping pills for sleep disorders. Among non-psychotropic drugs that can cause chronic dyssomnia, hormonal drugs, antibiotics, antimalarial, antiarrhythmic drugs should be noted. Caffeine and drinks containing it, steroids, thyroxine, bronchodilators and anti-asthma drugs, centrally acting antihypertensive adrenergic blockers, antiarrhythmic drugs, amphetamine and other psychostimulants, antidepressants (imipramine, some serotonin reuptake inhibitors), L-dopa, neuroleptics, smoking.
The use of these drugs can stimulate permanent or intermittent transient sleep disturbances. This group of insomnias includes a variety of sleep disorders in alcoholism. Most often, the phenomena of addiction and dependence develop with long-term use of benzodiazepine drugs (Phenazepam, Alprazolam, Diazepam) and drugs containing barbituric acid derivatives (Reladorm).
Insomnia in mental disorders
In the practice of neurologists and psychiatrists, insomnia is common in mental disorders. It is sometimes difficult to distinguish between a primary sleep disorder and sleep disorders due to psychiatric disorders. Insomnia often accompanies anxiety, depression, and panic disorder. A survey of doctors showed that 30% of patients diagnosed with insomnia were additionally diagnosed with depression.
Data from another study suggests that 40% of those suffering from sleep disorders have some kind of mental disorder. In 70% of patients with disorders of the neurotic circle, disorders of initiation and maintenance of sleep develop. Often, sleep disorder is the main symptom-forming factor, due to which, according to the patient, numerous autonomic complaints develop (headache, fatigue, blurred vision, etc.) and social activity is limited (for example, the patient believes that he cannot work, since he does not get enough sleep). Complaints of sleep disturbances may have intrinsic value in psychotic-level disorders and personality disorders.