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