With this specifier, the name provides most of the information. There has to be a clearly defined relationship between the onset and remission of depression with the changing of the seasons. For example, a patient becomes depressed in the late fall or winter and their depression remits once spring arrives. This is the most common pattern in clinical practice.

The relationship between the depressive episodes and season is present for at least the prior two years. Furthermore, the number of seasonal episodes is significantly more than nonseasonal episodes. Basically, what this means is there must be an established pattern related to the changing of the seasons for two years.

If the depressive episode is clearly related to another factor (e.g. start of school or change in work stats) the specifier does not apply. 

In the two-year period where the pattern is established there cannot be any nonseasonal episodes. 

For this specifier to apply, the person must clearly become depressed in the months where day light is reduced (possible mechanism for these episodes), and have remission of symptoms once the days become longer. (this is one example, there are others)

Like, Share, and leave a comment below if you ever felt depressed during the winter months