What could be the outcome of writing negative things about previous university in an application to another university?
Applications are places to write positive things, not negative ones.
Negative circumstances can paint you in a good light if you can describe how you have overcome those obstacles. Stated as you have here, the descriptions of your previous environment sounds more like blame, especially this part:

They are not at all helpful or encouraging. They always need to boost their ego, never ready to discuss anything, never ready to accept their mistakes if they made one. The teacher-student relationship is more like, dare I say, a master and slave type of relationship.

Maybe the blame is valid, however, when you talk negatively about someone else, people will reflexively wonder whether your complaints are justified, and they may worry you will describe them the same way. If you say your institution only drove you to memorization, how does this demonstrate you've developed skills related to research?
That said, mental health is very important, not for PhD applications but for you. I strongly suggest you seek professional assistance with those concerns - this is much more important than any PhD application.