The term is often used interchangeably with the term: winter depression, although in reality they are not synonyms. Depression can, in fact, repeat the fall or cover the entire autumn-winter season. Furthermore, there is summer depression, occurring less frequently but in some countries the indicator of the disease is high.
Seasonal depression does not have to also identify with seasonal affective disorder. The latter concept is broader and includes other forms of affective disorders repeated seasonally. This implies, in particular, bipolar disorders, in the course of which there are not only the depressions but also mania or hypomania.
