there’s a lot of psychology in chazal. umdenos, chazakos, maamarim about human nature (one who has 100 wants 200, hundreds more) Hashkofa and mussar seforim from rishonim and achronim are full of insights into psychology. Rav Nachman of Breslov mentions a treatment for OCD that was hundreds of years ahead of its time…because it’s from his torah, which is timeless.
Not all psychology requires a mesorah, and there is room for professionals like rabbi twersky to use evidence based approaches to deal with mental illness.
But milchemes hayetzer and tikun hamidos is not mental illness. It’s something that we have a mesorah for, a very clear one, too.
I don’t know why most posters here are conflating psychology with yiddishkeit. Not everyone needs a psychologist, not everyone needs therapy, and not everyone needs self-help books. It’s for people who have conditions. Mussar seforim is for everyone else.