I think you're exactly right. If you have a difficult childhood then your mind forms in abnormal ways, resulting in mental illness later in life and the inability to manage things like relationships in ways that everyone else can. I had parents who were divorced and who fought bitterly over me and my sister, and both tried to manipulate us against the other. It's only as an adult that I've realized how this resulted in my inability to seek and maintain healthy, functioning relationships, and in turn mental illnesses like persistent depression. I'm still coming to terms with this. I don't know if I'll ever overcome it.