Genetic changes in psychotic disorders

Two major psychotic illnesses, schizophrenia and bipolar disorder (also known as manic depression), are related disorders that may have similar genetic causes. These findings could lead to a better diagnostic test, early treatment and/or new treatment. Schizophrenia and bipolar disorder affect two percent of the population worldwide. They are incurable, chronic, relapsing disorders. Diagnosing and differentiating between the two is based on interviews with patients and the type and duration of symptoms. In manic depression patients get episodes of illness (highs and lows) and they recover when they are treated, whereas in schizophrenia the cognitive impairment is more profound and the patient has a social decline in most cases. Researchers at the Babraham Institute in Cambridge, England, discovered the abnormalities by comparing post-mortem brain samples from 15 people who had schizophrenia or manic depression and 15 others who did not. They found clear changes in key genes in patients with the psychotic illnesses.

They have shown that sufferers of the two disorders have abnormalities in key genes responsible for proteins in the central nervous system related to a compound called myelin. Myelin covers and insulates neurons, the nerve cells in the brain. They also confirmed earlier research that showed that patients with both disorders also have a reduction in brain cells, called oligodendrocytes, which make myelin.These results provide strong evidence for oligodendrocyte and myelin dysfunction in schizophrenia and bipolar disorder, and could form the basis of a diagnostic test to identify people at risk. If people at risk could be identified, they could be treated before they get the illness, since the evidence shows that having the illness causes the damage.

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