Brain structure

Abnormalities are apparent, both on naked eye (macroscopic) and microscopic examination, and on special investigation with brain scans (CT, MRI, and others). The brains of patients with schizophrenia tend to be smaller and lighter, and the normal fluid-filled spaces inside the brain (the ventricles) are larger. In particular, the temporal lobes of the brain (which are near the temple, and are to do with hearing) are smaller in schizophrenia; this establishes links with the possible source of auditory hallucinations, and ties in with the schizophrenia-like picture sometimes presented by patients who have temporal lobe epilepsy.

These structural changes are thought to reflect abnormal brain development in early life, but degeneration at a later date might also contribute. In support of the importance of brain damage are clinical observations that schizophrenia is associated with the following features:

• minor neurological signs (so-called soft signs)

• abnormalities on brain scan

• reduced intellectual function, including lower IQ and poor performance on tests of memory, concentration, and attention

• temporal lobe epilepsy of the dominant hemisphere

• birth complications, possibly involving mild brain damage due to lack of oxygen

• winter birth - possibly in association with the next feature

• maternal viral infection in pregnancy (although evidence for this is conflicting).

On microscopic examination, the neurons in this condition tend to be smaller and less richly connected to their neighbours; this would tie in with theories about 'neurodevelopment' as part of the pathological process.

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