Stress is a physiological neurohormonal reaction to external and internal influences, aimed at elimination of consequences of "damaging" factors, leading to disruption of the integrative activity of the brain and other systems of the body, and consequently to a decrease in certain functional capabilities of the person. Physiological stress was first described by Hans Sellier. He believed that "complete freedom from stress means death".
Stress can be caused by three main reasons:
- if a person's desires do not coincide with his or her abilities;
- if the external circumstances are such that a person has to change his or her whole life;
- if the person is affected by external, unusually aggressive factors related to the threat to life.
Hans Selliers described three stages of stress:
- “anxiety reaction” (accompanied by mobilization of neuroendocrine mechanisms (secretion of andreno-corticotropic hormone (ACTH), adrenaline, glucocorticoids increases);
- “Resistance stage” (characterized by restoration of balance between catabolic and anabolic reactions (secretion of anabolic hormones such as somatotropic hormone and insulin increases);
- The “stage of exhaustion” (develops when adaptive reserves are exhausted (the outcome may be the failure of adaptive mechanisms, the development of the disease or even death)).
The causes of stress (or stressors) are divided into two groups: physical and mental.
Physiological and psycho-emotional stresses are accordingly distinguished. At the same time, under the same conditions, stress may occur differently in different people, which, first of all, is determined by adaptation possibilities of a concrete person. It should be noted that an important role in the activity of anti-stressor mechanisms of the human body is given to sleep.
Sleep is a special genetically determined state of the organism, characterized by a natural sequential change of certain polygraphic patterns in the form of cycles, phases and stages. During one night a person usually goes through 4-6 sleep cycles consisting of different stages, which are characterized by a certain number of corresponding sleep phases (one such cycle lasts approximately 90 minutes). The structure of sleep is characterized by a slow sleep phase (anabolic function) and a fast sleep phase (information processing, creation of a behavioral program). Sleep and wakefulness periods in a person change with circadian periodicity. The period of circadian rhythms is usually close to 24 hours. The hormone regulating the circadian activity of the organism is melatoninin.
Currently, it is the adaptation (anti-stressor) sleep system that determines the degree of resistance of the body to various stresses. Its capabilities allow optimizing the body's adaptation to the environment during sleep and partially determine the stress resistance in general. The peculiarity of this system is that it actively works during the whole time of sleep, even in the absence of the action of the stressor.
Stressful reaction begins in awakening and continues during the night's sleep, and with prolonged exposure to the stressor - for several cycles of sleep-warming. The strength and direction of stress during the waking period is determined by a combination of both the strength of the stressor and the individual characteristics of the person (biological and psychological factors). Non-specific manifestation of stress is characterized by increased activity of ascending activating systems of the brain and is manifested in an increase in the representation of waking up during sleep and instability in maintaining the functional state of sleep. Various specific changes in sleep depend on the type of exposure and initial resistance of the body. These changes can be found not only in the intracorporeal but also in the posterior stage (a few days after the end of stress), which may cause the development of insomnia in the future. This leads to a "vicious circle" when stress causes insomnia and insomnia further increases stress.
Short-term stress exposure leads to episodic insomnia (up to one week). A study was carried out to study the main tendencies of changes in sleep structure under the influence of experimental conditions of short-term "isolation" (psycho-emotional stress). So, in the conditions of experiment there was a change of a base cycle of sleep-warming in comparison with an initial condition (the basic changes consist that subjects began to go to bed late (at 1 o'clock 15 minutes), time of falling asleep has been increased and has made 16,2 minutes (at a norm of 10 minutes), there was a long night awakening (for night 1 time with the subsequent falling asleep for 22,9 minutes)). Additional polysomnography confirmed the presence of abnormalities in the sleep structure, which were not constant, but were observed sporadically.
The main factor of insomnia chronification is stress persistence. Persistent stress with the subsequent development of a number of diseases may contribute to the persistence of stress:
- Hopelessness or uncertainty in a situation that is difficult to adapt to;
- High intensity or duration of stress response, resulting in depletion of adaptive reserves;
- Personal or biological characteristics that determine the weakness of anti-stress protection;
- Use of life-threatening techniques to protect against stress.
It is known that night work has a negative impact on a person's physical health. Negative consequences of night shifts for the body are caused by the fact that the human genes have a program, according to which he must stay awake during the day and sleep at night. For example, research conducted by the University of Chicago has shown that sleep disturbances affect the increase in blood sugar, which can cause diabetes mellitus. In addition, a number of studies have found that a person who works at night for a long time has a lower serotonin level in his blood, which increases the risk of depression and anxiety, which are themselves the main cause of chronic insomnia (lasting more than three weeks).
Depression (from Latin suppression) is characterized by pathologically reduced mood (hypothymias) with negative, pessimistic assessment of oneself, one's position in the environment and one's future. Depression ("mental cold") occurs in 2.5-5% of cases.
However, there is now a trend towards an increase in this pathology. Thus, according to the WHO, by 2020 depression will take the second place among the causes of disability (15% of the contribution) after coronary heart disease. Not without reason 20 years ago it was predicted that the "melancholy age" would come.
Depressive disorders are 1.5 times more common among women than men (average age 30 to 40 years). The prevalence of depression increases with age (on average 1.2-1.4 times every 10 years). Depression is characterized by recurrent depression. For example, more than 85% of cases have recurrent depression (on average, 3 episodes of 2.5 months' duration), and 10% have a rate of 10 or more.
The main diagnostic symptom of depression is low mood for two weeks or more. In addition to depressed mood, depressed patients have a 4-6-fold increase in the risk of complications and death from severe medical conditions, the risk of inadequate behavior in the disease (overdose or, conversely, abrupt withdrawal of medications (incompetence)), and reduced adaptive capacity and "quality of life" (18.1-52.3% of contributions).
Depression is currently being compared to "iceberg" (E. Wullf, 1978). Only 20% of depressive disorders have pronounced forms (the tip of the iceberg), which are not difficult for a psychiatrist to recognize.
However, most depressions ("erased forms") are placed in deeper areas of the iceberg. However, the number of patients who have never consulted a doctor is unknown. As a result, there is a high risk of suicide in depression.
Sleep disorders are an obligate sign of depression. Disruptions in the mediation of serotonin and melatonin, on the one hand, plays a crucial role in the development of depression, and on the other - is important in the organization of sleep.
Features of sleep disorders in depression: