One of the most poetic "texts" on this topic is the song written by for Michèle Arnaud in 1966.
In French, the term "papillons noirs" is a 19th-century metaphor for dark thoughts , worries, or melancholy. Lyrics Highlight: Les papillons noirs
The term is famously used in the poem (Night) from Albert Giraud's cycle Pierrot Lunaire (1884), later set to music by Arnold Schoenberg. One of the most poetic "texts" on this