Blood test for schizophrenia draws nearer

A blood test that measures the activity of genes can accurately detect mental illnesses such as schizophrenia, a small trial suggests.

RNA molecules are produced whenever a gene is active and, by measuring levels of these molecules in the blood, a team led by Ming Tsuang, at the University of California in San Diego has distinguished healthy individuals from patients with either schizophrenia or bipolar disorder (manic depression).These conditions are currently diagnosed by assessing patients’ behaviour. “A laboratory test would enable earlier diagnosis and more timely treatment,” Tsuang says.Tsuang’s team took blood samples from 74 patients, 30 with schizophrenia, 16 with bipolar disorder and 28 controls. They measured the levels of eight specific RNA molecules, all from genes linked to schizophrenia or bipolar disorder. The researchers could then tell the groups apart with an accuracy of 95 to 97 per cent (American Journal of Medical Genetics B, vol 133, p 1)Peter Liddle, co-director of the Nottingham Institute of Neuroscience in the UK, warns that the similarities in gene expression in patients could be a coincidence or the result of their medication. Tsuang is already carrying out a second, larger study and hopes to start a third with patients not on medication, to rule out possible effects of prescription drugs on gene expression.(Source: From issue 2485 of New Scientist magazine, 05 February 2005, page 14.)