The holidays should be a joyous time for everyone, but often those who are overworked and overwhelmed with circumstances in their lives can possibly become depressed.
I was doing some depression research and it seems that it can be common for people to fall into depression during the winter. I can see that, because November, December and January can be stressful months. Perhaps it has something to do with the weather, or maybe the holidays or maybe both of them combined along with other personal circumstances. Pile all those things on top of each other and one can feel extraordinarily worn down during this time of the year.