It seems more and more like a bunch of people with various curses, possessions, or mind wipes. Nothing really about real life mental health issues. Although talking it out should probably be part of dealing with it, just not all of it, and there's never a magic bullet to fix it.
Exactly, seems it's more about curses or possession! While there's some indication of mental issues, maybe it's not even done on purpose! The saintess anxiety and insecurity made her irrational, leading to mistakes, but her maid,instead of calming her down and reassuring her, made everything about herself, saying the saintess doesn't trust her! Basically just worsening her anxiety! The heroine attitude changed and her desire to protect her friend getting warped (I was spoiled what's going on, more or less), but that same friend did nothing to help her, talk to her! After defeating her, he left her there not even asking what's going on with her! She finds him again, revealing she's in love, but he locks her in the tomb!? Wouldn't be normal for a childhood friend to sit somewhere calm and talk it over? It's our own fear of confrontation and avoiding "problematic" people that leeds to them getting worse! But maybe I'm just projecting my own experiences and reading too much into it