What is anxiety disorders and schizophrenia have in common and how do they differ?

Very different : Schizophrenia involves delusions, hallucinations (mostly auditory), disorganized speech, disorganized behavior, and negative symptoms (flat emotion, low production of speech, goal directed behavior). Distortions of reality so to speak; anxiety disorders involve experiencing the process of anxiety chronically (preparing the body to cope with future threat) and fear in the case of panic and phobias.

Different illnesses: Anxiety disorders are noted for primarily having either a high baseline level of anxiety (obsessive compulsive disorder, general anxiety disorder), or intermittent, episodic anxiety (panic disorder), as their main characteristics. Schizophrenia is mostly noted for lack of emotion, disconnection with the external world, cognitive difficulty, and psychosis. They are both psychiatric illnesses.