Is one allowed to take a cold shower “to promote well being” and ” relive depression” in the Nine days
The terminology to “promoting well being” does not permit taking a shower, because everyone feel better after they take a shower, and if this would be custom wouldn’t exist!
Regarding “relieving depression”, if the person is not well, and it isn’t being done for pleasure, but for a medical reason then it is permitted. It is difficult to categorize what this means in such a forum.
Leket Yosher pg. 109, Darcei Chaim V’shalom 665,Horav Eliyashiv zt”l brought in Halichos V’hanhagos pg. 12, Kol Hamisablim Aleha 11-5.