Statistics show that low temperatures and long new year's holidays. According to the data on mortality of the population, in most countries, January is in the first place by the number of deaths in other months, and for specific reasons.
Scientists believe January the most depressing month, despite the holidays. Person in January, worried about a lot of money spent over the weekend to thoughts of a distant summer and need to get through 3-4 cold months.
Psychologists share the position of scientists. According to them, January is a period of "unrealized expectations". People at this time often lost motivation, mood. Many expect that the holidays will lives, but this does not always occur.