Major psychotic illnesses linked to genetic changes

LONDON - The two major psychotic illnesses, schizophrenia and bipolar disorder, are related disorders that may have similar genetic causes, say British scientists.

Their findings could lead to a better diagnostic test, early treatment or new drugs for the illnesses.

Researchers at the Babraham Institute in Cambridge 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 insulates brain cells or neurons, like using plastic to protect an object from damage.

"We found abnormalities in the proteins which compact the myelin," Dr Sabine Bahn said in an interview.

She and her colleagues also confirmed research which showed that patients with both disorders also had a reduction in cells in the brain called oligodendrocytes, which make myelin.

"We believe that our results provide strong evidence for oligodendrocyte and myelin dysfunction in schizophrenia and bipolar disorder," Dr Bahn said.

Schizophrenia and bipolar disorder, or manic depression, affect about 2 per cent 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 you treat them, whereas in schizophrenia you have a social decline in most cases and the cognitive impairment is more profound," Dr Bahn said.

The findings, reported in The Lancet medical journal, could form the basis of a diagnostic test to identify people at risk of the disorders, she said.

"If you know people who are at risk of the diseases you can treat them before they get the illness because the evidence is that having the illness causes the damage."

Scientists discovered the abnormalities by comparing autopsy brain samples from 15 people who had suffered schizophrenia or manic depression and 15 others who had not.

They found changes in key genes in those with the illnesses.

- REUTERS