There's a technique from CBT I found helpful, it isn't a cure but I wish I had learned it 10 years ago:

When you're depressed, and you're thinking "life sucks," you reframe it by saying: "my depression says my life sucks." You come up with an image of the thing, ideally a small black and white one, and attach the statement to that. The book I read suggests using a damp blanket over your face to represent depression.

What you do is externalize your state to something outside of yourself that is trying to convince you of things. You characterize it a bit. What it does is keep yourself from identifying with it, and helps you be able to be objective about addressing it.

Its sort of a habit, not something you can do once a day for 15 mins and cure yourself with.

Another example: if you're angry and you are thinking "I'm going to KILL that cat!" you might instead imagine a cursed, flaming sword with the voice of the blood god Khaine (I play D&D haha) and think "My anger/rage is saying I should kill my cat," and you'll sort of see that it isn't you that thinks X, it's an idea put forward by something you're externalizing from yourself. It loses a lot of power over you.