Site  contains material that is claimed to be an evidence that schizophrenia is a brain disease. The site discusses mainly massive loss of brain cells (although some other topics are covered). However, many of the studies deal with adolescent people. Massive loss of brain cells is a normal process in teenage brain. However, it has been argued that the loss of brain cells is more extensive in schizophrenic brain compared to teenage brain. Site  says:
Now, imaging technologies let us visualize even more remarkable changes in the brains of children and teens. Using MRI scans, we can watch teenagers' brains change in miraculous patterns as they grow up. We recently created the first maps of brain growth in individual children and teens. To our surprise, an extraordinary wave of tissue growth spread through the brain, from front to back, between the ages of three and 15. Frontal brain circuits, which control attention, grew fastest from ages three to six. Language systems, which are further back in the brain, underwent a rapid growth spurt around the age of 11 to 15, and then drastically shut off in the early teen years. This language system growth is interesting, as it corresponds to the end of a period when we are thought to be most efficient at learning foreign languages. Perhaps the biggest surprise of all was how much tissue the brain loses in the teen years. Just before puberty, children lost up to 50 percent of their brain tissue in their deep motor nuclei -- these systems control motor skills such as writing, sports, or piano. This loss moves like a wildfire into the frontal lobes in late teens. We think it is a sign of rapid remodeling of brain tissue well into the teens and beyond.
Site  also claims that the denial of the existence of schizophrenia by the patients has an organic cause:
Impaired Awareness of Ilness: Approximately 50 percent of individuals with schizophrenia and manic-depressive disorder, including those who have never been treated, have impaired awareness of their own illness. This has been shown in at least 50 different studies. Such individuals do not realize that they are sick, and they will, therefore, usually not accept treatment voluntarily. Studies suggest that this impaired awareness is probably related to the decreased function of the prefrontal area of the brain.
These individuals are thus similar to some patients who have had a stroke and, because of brain damage, are unaware of their disability and deny it. The lack of awareness of illness in individuals with schizophrenia and manic-depressive disorder is the most common reason that they do not take their medication. [as can be seen in the research below, the part of the brain that is resonsible for self-analysis seems to be one of the areas most damaged by schizophrenia; the brain that is damaged, cannot frequently recognize that it is damaged]. This is a problem is because increasingly schizophrenia research is suggesting that the sooner a person with this brain disease is treated, the better the outcome for the person. Delays for treatment result in much worse outcome (see recent research below).
This is an absurd and dangerous claim. If a patient can't analyze his own "illness" how can he think at all? Denying schizophrenia is also completely different thing than denying a stroke. A human being has no senses that feel what is happening inside the brain. I wonder how the authors define "self-analysis" and how it differs from ordinary thinking. Psychiatric diagnoses are often pseudoscientific and dishonest and they are rarely based on any evidence about physical changes in the brain. Psychiatry may also classify resisting "treatment" or other antiauthoritarian rebellion as a symptom of illness. Disagreements about this kind of ideological questions can't be regarded as things caused by a brain damage.
It is also interesting to think what it would mean if schizophrenics and other people did have differences in brain. Then we would have to ask what these differences actually cause. If psychiatrists classify e.g. antiauthoritarian rebellion as a symptom of schizophrenia then it does not matter if it is caused by different kind of brain or not. It is simply not a sign of an illness. Psychiatrists' definition of a delusion is extremely vague and they do not have to prove their claims when they say that someone is delusional. Differences in brain or brain illness are no reason for the suppression of civil rights of the schizophrenics. People with different brains could be also regarded as just an another minority.
 URL: http://www.schizophrenia.com/disease.htm
 URL: http://www.pbs.org/wgbh/pages/frontline/shows/teenbrain/work/how.html