It has been found experimentally that a change in biological rhythms in the human body occurs by its source of heightened intensity light. It were some attempts to prevent the seasonal exacerbation of depression by means of “lengthening day” with the help of lightage and sleep deprivation.

It is supposed that bright and long effecting light affects circadian rhythm, oppresses in epiphysis (endocrine gland which regulates other organs of endocrine system) melatonin secretion, causes changes of cortisol concentration as well as ACTH in patient’s blood. It also changes the catecholamines synthesis and has sympathicotonic and parasympathetic (at the expense of calorific effect) effect. In the end, these changes lead to treatment of depression.

For therapeutic action it is necessary to have room lighting at least 2600 and no more than 8000 luxes.

Necessary lighting is achieved with a help of incandescent lamps, located on the ceiling chamber at a height of 2.5 meters. Usually are used 27 incandescent lamps of 200 Watts. It was noted that the effectiveness of treatment with light increases by coloring the therapy rooms in the white or green, as well as by maximum (25%) naked body. Before a light therapy the patient is carefully examined. The treatment of depression with light can be conducted at any time of day, also with two-day or three-day intervals. During the conversation, patients who are only asked not to shut their eyes can freely move around the room.

Seasonal affective disorder can have the same symptoms as a depression, which are not connected with the certain season. It may be depressed mood, melancholy, anxious feeling, apathy, joylessness or hopelessness. Rarely these symptoms are more pronounced in the first half of the day, whereas to the evening the state becomes better.

More typical for seasonal affective disorder are considered other symptoms. Patients, suffering from seasonal depressions, parallel with depressed mood, anxious feeling and decreased activity, experience drowse and keen appetite during the whole day. During depression they consume more food which is rich in carbohydrates. They can also put on weight. As a rule, reduces the overall tone, but appears weakness and variety of unpleasant sensations in the body.

Asthenic symptomatology of seasonal affective disorder is following: feeling of weakness, flabbiness, souse and all-overishness. It may be different pains and unpleasant feelings in the body. The mental work decreases, the memory and attention worsen. It is significant that intensity of these symptoms practically do not depend on outside force and quite often they are more pronounced in the morning hours after awakening.

In development of seasonal affective disorder the important role plays metabolic serotonin – biologically active substance, which regulate mood.
Experimental researches have shown that in winter the content of serotonin lower than in summer. The significant regulator of serotonin is melatonin – an active material, which production depends on light quantity.

The classical approach of seasonal affective disorder treatment is light therapy. Besides, it has been proved high efficiency of antidepressants with a specific action on the exchange of serotonin in the brain. Prolonged use of these medicines allows not only cure developed depressive state, but also to prevent their future development. As by other depressions, the essential element of effective treatment is psychotherapy