Modern psychiatry uses a theoretical concept of ‘disorder’: it describes various impaired functions without distinguishing pathological disorders from non-pathological disorders, or even from disorders similar to an illness. Of course, this usage eliminates neither illnesses nor the subjective experience of being ill, but it has implications for forensic psychiatry and for the assessment of a person’s legal responsibility. Having schizophrenic delusions constitutes a categorically different state from having only wishful illusions or a vivid imagination. In the context of medicine and psychiatry, we certainly encounter stages that signal fundamental differences. These differences are easily detected when assessing psychotic disorders or similar states, but a lot of differences also arise when assessing perpetrators with personality disorders or simply antisocial behavior. Where, in these states, are the borders that demarcate full responsibility from substantially reduced social responsibility?