The next disease we will discuss is schizophrenia.
The good depiction of this disease would be Parry in the Fisher King. This is far more common in real life than pure sociopathy. It is a product of nature, not nurture (Fisher King notwithstanding), and it has profound effects on the sufferer. This is the paranoid; the one who hears voices. This disease strikes at all socioeconomic levels, but consistently results in lower socioeconomic levels. Because it is very difficult to medicate, it frequently results in the sufferer being unable to hold a job or function in society. To draw a true schizophrenic, you have to remember that there is a certain pathos to these characters, regardless of what crimes they might commit. They do not pre-meditate, plot or scheme. They do act from the confused jumble of their brain. A schizophrenic has trouble distinguishing the real world from the one inside their head, and will frequently obey the voices they hear, and the people they see in their minds. These are the people for whom the 'by reason of insanity' plea exists.