Biology 202
2002 First Paper
On Serendip

Neuropathologists have been researching schizophrenia for approximately a hundred years. But, even with a hundred years of research, the neuropathology of schizophrenia is still obscure. Although scientists have come a long way since the beginning of research, when they first believed that it was a "functional" psychosis, a disorder with no structural basis," the cause of the chronic disease remains a mystery" (1). However, with technological advances in science, researchers have found a common trend in diagnosed patients- physical abnormalities of their brains. These revelations cause scientists to wonder if brain abnormalities are a cause for schizophrenia and, if so, how these abnormalities arise.

Schizophrenia has long been considered the "graveyard of neuropathologists" (1). This chronic and disabling brain disease is characterized by a relapsing psychotic disorder that primarily affects the thought and behavior of the affected person. Although symptoms may vary from patient to patient, common ones include disturbances of thought, auditory hallucinations and multiple delusions. (2) If all this is known, why is schizophrenia the graveyard of neuropathologists? Although the symptoms are now relatively simple to diagnose, neuropathologists still do not know what causes this disease. Many diseases are caused by genetic, behavioral and other factors, making scientists theorise that this is the cause of schizophrenia as well. However, neuropathologists still do not understand all the factors necessary for schizophrenia to exist. (6)

With relatively recent technology of MRI scans, CAT scans, and PET scans, scientists have discovered that many patients with schizophrenia have physical abnormalities in portions of the brain. CT and MRI studies have improved resolution and sophistication of analyzing brain abnormalities in people diagnosed with schizophrenia, allowing many abnormalities to be identified, including ventricular enlargement and decreased cerebral volume. Brain ratio, or VBR, indicates an increase of 20-75% of the lateral ventricle while MRI studies show a median 40% increase in ventricular size. The enlargement of the lateral ventricle is accompanied by an average 3% loss of brain tissue, in which reduction is relatively greater in the axial than the sagittal plane, suggesting a relative decrease in mediolateral breadth and a greater involvement of regions which are typically included in axial slices, such as temporal lobes (1) There are also a few MRI studies which suggest that the thalamus is smaller in patients with schizophrenia; although this evidence is weak, it is complemented by strong neuropathological data.

However, many scientists emphasize that some of the abnormalities researched are quite subtle, in that these abnormalities have been found not to be 1) characteristic of all schizophrenia patients or 2) to occur only in individuals with schizophrenia (5). Also, although the structural pathology has been observed in schizophrenia patients, the brain abnormalities developed do not correlate with the disease duration. Abnormalities found in patients with schizophrenia remain relatively the same throughout the progression of the disease. Researchers have found that VBR and ventricular increase and brain tissue loss do not change drastically in patients with schizophrenia. This suggests that the alterations are largely static, and there is relatively no progression in the reduction of brain tissue, or increase in VBR (1).

Even though these technological advances have allowed neuropathologists to discover that brain abnormalities are characteristic in schizophrenia patients, how do these physical abnormalities develop? Developmental neurobiologists have found that schizophrenia may be a developmental disorder resulting when neurons form inappropriate connections during fetal development (6). However, symptoms of schizophrenia generally appear during adolescence or young childhood, when the body is undergoing the hormonal and physical changes of puberty. It has been suggested that the disease remains "dormant" during childhood, proposing that patients are born with schizophrenia and do not display the symptoms until adolescence, when the disease emerges (3). If this is the case, then perhaps it is the brain and body changes that occur during puberty that arouse the inappropriate connections during fetal development and result in the emergence of schizophrenia. Scientists have in fact discovered patterns of brain development that extend into the teenage years. Prior to this research, neuropathologists had observed brain development in the womb and in the first 18 months of life; but recently researchers have discovered structural changes that occur much later in adolescence (4). With this study, it becomes more likely that schizophrenia remains silent until adolescence, when brain abnormalities are formed during structural changes.

With new scientific technology, research in schizophrenia has been favored in that the discovery of brain abnormalities in schizophrenia patients help the search for the cause of this disease. It has become more likely that schizophrenia remains dormant until adolescence, when structural changes to the brain are being made resulting in the physical brain abnormalities found in patients diagnosed with schizophrenia. However, these recent studies arise some questions on the cause of this disease. What causes these brain abnormalities? Are these abnormalities spontaneous, are they genetic? Schizophrenia has shown hereditary trends; perhaps there is some genetic mutation which causes the abnormal brain development during adolescence. Although the cause is still unknown, the technological advances of MRI scans and CAT scans have moved the research foreword, hopefully finding a cause for this chronic disease in the near future.

References

1)The Neuropathology of Schizophrenia, a critical review of recent brain abnormality data and its interpretation

2)The Aetiology of Schizophrenia, a description of the possible causes for schizophrenia

3)Schizophrenia, background information concerning this disease

4)Teenage Brain: A work in progress, recent research concerning structural changes of the brain during adolescence

5)Schizophrenia: Questions and Answers, a source answering the most common questions about this disease

6)Schizophrenia, basic information on schizophrenia

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