The man has multiple disorders including substance abuse disorder.  It seems as if misuse of drugs and/or alcohol is triggering other more serious and dangerous mental disorders. Increasingly you see delusional people, often male, rambling and ranting down the street. I wonder if this man's problems started with drugs.   On the one hand you don't want to punish people for being mentally ill, yet on the other, the horribleness of the crime creates a sense that maybe this fellow will never be safe out in the general public, especially if he relapses to his addiction.