What meds do to the brain?

I was looking at some examples especially the children camps like the one where Paris Hilton was locked once, they were giving pills to those teenagers that are keeping them numb and weak.
I know peps who are taking those meds, a girl with me she is so damn fat but she’s working a lot.
All people I know who are taking those pills become fat as hell but they work non stop.
What is in those pills?
I am thinking about seeing a psychiatric, I think I have depression, PTSD and anxiety.
I don’t want to be fat tho, I just want to get rid of the symptoms.