It has long been known that the environmental variations related to the seasons can influence man’s behavior and mood.
Hippocrates was the first, in the 400 BC, to describe a Depressive disorder linked to the seasonal trend And, in the second century BC, Greek-Roman doctors used to treat depression with exposure to sunlight directly in the eyes.
Pinel and his pupil Esquirol (1845) were instead the first to distinguish the Summer and summer depression subtypesbut only in 1984 Rosenthal and colleagues described the diagnostic criteria of the so -called “Seasonal affective disorder“(Sad), characterized by depression in autumn and winter and periods of well -being in spring and summer.
Sad is a chronic pathology that has cyclic depressive episodes. Its most common symptoms are:
- Hypersonnia or insomnia
- hyperphagia (with particular predilection for carbohydrates), with consequent weight gain
- mental and physical tiredness
- lack of energy
- Concentration difficulty
- general sense of confusion
- irritability.
Although the seasonal affective disorder has been widely recognized by the scientific community, however in the DSM-IV it did not appear as an autonomous nosographic category, but rather as a method of decorating mood disorders; From a clinical point of view, the symptomatology that characterizes SAD patients falls between the depressive events that the DSM-IV described as “atypical”.
In in fact, in patients with Sad, the mood, although depressed, presents itself as a reactive (i.e. those who are affected are capable of rejoicing when they are faced with positive events, see DSM-IV).
There Deflexion of mood toneFurthermore, it is typically accentuated in the evening; Other “atypical” depressive symptoms that are found in patients suffering from this pathology are hyperphagia, ponderal increase, hypersonnia, anergy and lethargy.
Based on the course, two forms of SADs are distinguished: the “winter form” and the “summer form”.
In the “winter form”, which represents the prevalent presentation method, the depressive symptomatology begins during the autumn season, reaches the maximum of the intensity during the winter season and is resolved, partially or totally, at the beginning of the spring season.
In the “summer form”, on the other hand, the depressive episodes occur at the beginning of the spring season, reach Acme in the summer and resolve at the beginning of the autumn season.
As previously mentioned, until the last edition of the DSM, this disorder was not cataloged as a specific nosographic entity, but as a simple form of Depression with cyclical and regular trend.
In the last recent edition of the manual (DSM-5), however, the Seasonal affective disorder It is described as a real diagnostic category and as this treaty.
Several theoretical models have been developed capable of explaining the pathophysiology of the Sad, but only recently the question has been asked about what can really be the cause of discontent, sadness, melancholy or depression in some people, precisely during these periods of the year.
Perhaps the researchers of the University of Copenhagen managed to answer the question, with a study whose results were predated to the XII International Conference on Neuropsychopharmacology of London.
The problem, according to what emerged from the studies of Dr. Brenda Mc Mahon and colleagues, would be to be found in the levels of serotonin production, which would change according to the seasons and the amount of light present. People who develop the Sad would therefore have a problem with serotonin and Sert levelsthe conveyor of this neurotransmitter, not even called a good mood hormone.
To observe what happens in people’s brains, researchers recruited 11 people with Sad and 23 healthy volunteers for comparison. Using a positron emission tomography (PET), they performed brain scans: they were thus able to observe significant differences from summer to winter in the Sert levels in patients suffering from Sad.
In particular, the volunteers with Sad had higher levels of Sert in the winter months, which correspond to a greater removal of serotonin in winter, while this did not happen with healthy volunteers. According to researchers, these results confirm what others have previously suspected.
«We believe we have found the way the brain transforms when he has to adjust the serotonin to change the seasons – explained Dr. Mc Mahon – The transporter of serotonin (Sert) leads serotonin back to the nerve cells in which it is not active, so that the higher the Sert activity, the lower the activity of serotonin “.
«The sunlight maintains this naturally low setting – adds the researcher – But when the nights stretch during the autumn, the levels of Sert increase, with consequent decrease in active serotonin levels. Many people are not really affected by the Sad, and we have discovered that these people do not have this increase in Sert activities, so their active serotonin levels remain high throughout the winter “.
The Seasonal affective disorder It is however quite widespread; About 20% of the American population suffers from it and about 12 million people in Northern Europe alone.
“We know that a balanced diet, reducing the intake of caffeine and doing some exercise can help, as well as spending as long as possible in the open air, because even when it is cloudy the light is always higher than closed.
Certainly it is a disorder not to be underestimated and to be treated also with the support of prepared and competent specialists “, concludes Dr. Mc Mahon.
Currently, there are two types of Evidence-based treatments which are effective for the SAD: drug therapy with antidepressants and phototherapy (whose effectiveness has been demonstrated in various studies).
Phototherapy is currently considered the first method of treatment for the SAD, first foarmacological therapy based on antidepressants is adopted.
