This isn't necessarily true, depression can have quite different faces. ICD-10 differentiates between * major depressions with a single episode (F32 - this is

This isn't necessarily true, depression can have quite different faces. ICD-10 differentiates between * major depressions with a single episode (F32 - this is probably what you had in mind) * recurrent episodes of various degrees (F33 - this includes seasonal affective disorders, i.e. recurring winter blues) * Persistant mood disorders like dysthymia, where your baseline mood is dysphoric (F34.1)