If your depression and anxiety were successfully co treated, meaning the depression lifted and you did not experience panic attacks, then your mind would have concrete evidence that it is possible to live a life without them. Through meds and therapy the thinking patterns and defense mechanisms you now have would be challenged. They may even be proven false. You will never know unless you challenge them.

Of course a life of constant depression or everyday panic attacks would be horrible. Many of us here know it all to well. The point is to challenge your belief that it will never change.