Neuropathology

It is believed by some that schizophrenia is a mental illness caused by a chemical imbalance of Dopamine and Seratonin; neurotransmitters that are significant in their ability to function as both excitatory and inhibitory. This, based on my research, has not shown to be the case. Rather than a simple chemical imbalance, there have been studies to show resemblances in all if not most of the brains of those diagnosed with schizophrenia. Tests showed that blood flow was lower in frontal regions in afflicted people when compared to non-afflicted people. This condition has become known as hypofrontality. Other studies illustrate that people with schizophrenia often show reduced activation in frontal regions of the brain during tasks known to normally activate them.

Some studies have found the hippocampus and amygdala to be reduced in volume. Also, components of the limbic system, which is involved in the control of mood and emotion, and regions of the Superior Temporal Gyrus (STG), which is a large contributor in language function, have been notably smaller. The Heschl's Gyrus (which contains the primary auditory cortex), and the Planum Temporale are diminished. The severity of symptoms such as auditory hallucinations has been found to be dependent upon the sizes of these language areas.

Another area of the brain that has been found to be severely affected is the prefrontal cortex. The prefrontal cortex is associated with memory, which would explain the disordered thought processes found in schizophrenics. All of these abnormalities in brain function and structure size have pointed to the fact that all, if not most, people with the illness have increased ventricular space. Enlargement of the lateral cerebral ventricles is one of the earliest reported structural brain imaging abnormalities found in schizophrenia, as well as one of the most stable findings in morphometric investigations. However, it is unclear whether ventricular changes are related to focal or diffuse volume reduction of brain parenchyma. Previous studies have implicated preferential enlargement of certain parts of the ventricular system, such as the temporal horn or body of the ventricles. This might suggest that ventricular enlargement in these patients is related to specific shrinkage of gray matter or white matter structures, rather than diffuse brain atrophy. Structures implicated in schizophrenia such as the thalamus, hippocampus, or corpus callosum are located adjacent to or near the ventricles and show structural alteration in schizophrenia.

References:

http://brain.oxfordjournals.org/content/122/4/593.full

http://www.nature.com/mp/journal/v6/n6/full/4000956a.html