Seasonal affective disorder (SAD) is a form of depression that people experience at a particular time of year or during a particular season. Most of us are affected by the change in seasons it is normal to feel more cheerful and energetic when the sun is shining and the days are longer, or to find that you eat more or sleep longer in winter. However, the change in seasons will have a much greater effect on your mood and energy levels, and lead to symptoms of depression that have a significant impact on your day-to-day life.
Most of the patients with SAD become depressed in the winter, at least in part because of a phase delay in circadiac rhythms relative to the sleep/wake cycle. Seasonal mood symptoms suggest that genetic aberrations may underlie the various abnormalities, which cause SAD symptoms are, Eat more and crave carbohydrates, such as bread and pasta, Gain weight, Sleep more but still feel tired, Have trouble concentrating. Medication of drug Melatonin secretion occurs later in the night.
The prevalence of SAD and S-SAD were estimated at 4.8% and 9.5%, respectively, which is signifi- cantly lower than prevalence rates obtained with the same method (?2=9.29 and 7.3; P<.01). The standardized rate ratios compared with other states were 0.49 and 0.63 for SAD and S-SAD, respectively. No case of summer SAD was found.