All patients must meet the diagnostic criteria for recurrent major depression or bipolar mood disorder. Seasonal affective disorder (SAD) is then a sub-type specifier used to describe temporal variations of these disorders. As such, SAD is not considered a stand-alone diagnosis or comorbid condition to recurrent major depression or bipolar disorder. Common presentations include the initiation or worsening of depressive symptoms during the autumn or winter months, and full remission during the spring or summer months, or hypo-manic or manic symptoms presenting during spring or summer months.
Circadian and neurotransmitter factors are likely to contribute to the pathophysiology of SAD, although the exact mechanism of action remains ill-understood. The suprachiasmatic nucleus (SCN) of the hypothalamus is being increasingly recognised as the 'master regulator' of several systems implicated in seasonal mood regulation. Diminished light during the autumn and winter may cause a phase shift in various circadian rhythms, including sleep-wake cycle, body temperature, hormone levels, and melatonin secretion.
The year 1965 introduced the modern epidemiological crisis in Russia. For the period of gradual mortality increase (1965-1980), we point out a divergence in mortality trends among different age groups, focusing on causes of male mortality in their active ages (15-64). Next, we analyze the dramatic mortality fluctuations that have occurred since 1985. They include at least three components. These are: 1) the long-term unfavorable mortality trend; 2) the mortality decrease and then increase caused by the anti-alcohol campaign of 1985-87; and 3) the sharp mortality increase of 1992-93. The paper concludes with some speculations on the main factors likely to be contributing to the recent epidemiological crisis in Russia.