I the seasonal affective disorder is a disorder of mood triggered by the change of season or perhaps more specifically, dall'accorciamento of days that occurs in autumn and winter.
A from September to March than SAD sufferers are unable to adapt their physiological rhythms with the decreased exposure to daylight and become, first and only physically then psychologically, distressed and disturbed.
A ow many specialists believe that the symptoms of depression associated with SAD are due to a change in the circadian rhythm, caused by a biological dysfunction - a reaction to the darkest days and short autumn and winter.
P ince is the pineal gland che reagisce alla luce e la sua secrezione di melatonina è un fattore chiave della regolazione del ciclo circadiano e di quelli a esso correlati, la ricerca sul SAD si sta concentrando sulla fondamentale interazione tra luce, melatonina e altri ritmi variabili che regolano la concentrazione delle sostanze chimiche dell'organismo.
I l SAD colpisce circa una alta percentuale della popolazione ed è tre volte più probabile nelle donne rispetto agli uomini. L a vita femminile è più soggetta ai cicli biologici (come quello mestruale) than men, so it is easier for women to be exposed to the adverse effects of a disorder in their biological rhythms.
P s far since the days of Hippocrates, doctors have observed a seasonal change in mood, the SAD has not been officially recognized as a disorder of tone and 'spirits up in the early eighties.
I the Dr. Norman E. Rosenthal, a researcher at the National Institutes of Health, was the first to identify SAD and to establish a link between a particular type of behavior and the onset of winter.
S ccording to the Diagnostic and StatisticalManual of Worth Disorders, the official guide to psychiatric disorders, there are some specific criteria for the diagnosis of SAD :
1. There is always a correspondence between the onset of major depressive episodes and a special year.
2. The individual experiences a complete remission or mitigation of depression at any one time of year.
3. Over the past two years, there have been two major depressive episodes that demonstrate the link between the episode and the season, while there has been no incident outside of that time.
4. During the life of the individual, the observed seasonal depressive episodes outnumber non-seasonal.
U no predominant aspect of SAD is the seasonal change in dietary habits, usually characterized by an increase in appetite, which causes a strong desire to carbohydrates.
D the usual, most of us change the diet during the colder months, eating more hot foods, and reducing consumption of salad and fruit, because of the limited variety of fresh produce available.
D the itself this is not something particularly significant, but in people with SAD, dietary changes are related to mood, more specifically . During the winter months, they reported an increased consumption of bread, pasta, pastries, potatoes, chocolate and candy. The consumption of caffeinated beverages is growing substantially.
Q hen was asked these patients to choose foods of this type, the reason given was never hungry, but the desire to combat stress, anxiety or mental fatigue.
D opo ate, in fact, the majority of SAD patients reported feeling more calm and clear mind.
Q T his fact has a base fisiologica. Sembra che i cibi ricchi di carboidrati accelerino la produzione di serotonina, un agente prodotto dalla pineale che funziona da neurotrasmettitore cerebrale.
L a setotonina è anche un precursore della melatonina , il che significa che, quando il corpo lo richiede, viene convertito in melatonina .
S i crede che la serotonina svolga un ruolo importante nell'alleviare certe forme di depression, and that the transmitter acts as fluoxetine, an antidepressant of the most popular and effective.
I nsieme intense cravings for carbohydrates, patients with seasonal affective disorder have a number of other symptoms.
T etween 1981 and 1985, the National Institute of Mental Health has reviewed more than fifteen hundred cases and has developed a statistical profile of the disorder.
Among other things, these data have emerged:
1. 96% of SAD patients reported being less active in winter.
2. 94% stated that during the winter months there are problems in interpersonal relationships with spouses, lovers, family members, friends and colleagues.
3. During the winter months 96% of patients with SAD experienced feelings of sadness, 84% suffered from anxiety and 79% reported increased irritability.
4. 88% said they had difficulty at work.
5. In these patients has shown increased appetite and a general change in body weight. More than seven out of ten patients showed a weight gain.
6. More than six out of ten patients reported decreased sexual drive.
7. Some patients have found that symptoms of depression have improved in an extraordinary way at the time of travel brought them near the equator, where the duration of day and night are equal.
M hile some of the symptoms of seasonal affective disorder also appear in other forms of depression, the particular combination of lethargy, anxiety, irritability, and changes delle abitudini alimentari con cui il paziente tenta di fronteggiare i cambiamenti stagionali rappresenta un disturbo specifico. E chiaro che il SAD è provocato dall'incepparsi della ciclicità dei livelli degli ormoni e di altri composti chimici che governano il ciclo circadiano, per il cui mantenimento l'esposizione alla luce è fondamentale.
S i sta ancora indagando per scoprire esattamente come e perché questa interruzione dei cicli biologici avvenga in alcune persone e non in altre.
C ome I said before, most of our body functions, including physical activity, sleep , feeding, drinking and maintenance of body temperature , follows the circadian rhythm.
A ltrettanto also applies to the cyclical pattern of blood levels of key hormones and enzymes, which can profoundly affect the mood. The control of these rhythms is largely a function of time when we are exposed to the light and the duration of such exposure.
The researchers are now exploring the relationship between the various symptoms of depression is known that they are related to fluctuations in the levels of compounds chemicals in the body, and more particularly the melatonin.
The role of melatonin
A lthough the cause of the affective disorder of depression vacation is not known, the research conducted so far suggest that SAD is triggered by a disturbance of the seasonal cycle of melatonin , leading to an imbalance in the circadian cycle.
N she majority of patients with SAD, melatonin levels do not exhibit the normal fluttuazioninotturne. Under normal conditions, blood levels of this molecule is expected to peak around 2 am, and then decreased.
E 'was found in patients with SAD, however, melatonin levels remain high for about two hours longer than normal, before beginning to decline.
is been well documented that, when the levels of melatonin are abnormal (too high or too low), symptoms may occur related to mental disorders. For example, recent studies have shown that levels melatonin are too high in people with manic disorders (which are subject to extreme changes in mood), while abnormally low in people suffering from depression .
In depression fact there is a 'melatonin-deficiency syndrome' , characterized by low blood levels of this molecule and disorders of circadian rhythms that regulate the production of stress hormones.
C omunque, it seems that the irregular production of melatonin is only one of the mechanisms that produce the main symptoms of SAD.
At this point it is unclear whether the melatonin is directly responsible of seasonal affective disorder, or if the anomalies detected in the secretion of this molecule are simply a by-product or a sign of the disease.
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