A COMPUTER is as good as a psychiatric nurse at diagnosing mental illness, a new study reveals. Eighty-six patients in a south-east London general practice were asked to fill in a computer questionnaire about their symptoms, designed to detect depression, irritability, anxiety, phobias and obsessions. An analysis of the results, published in the Journal of Epidemiology and Community Health, found that the computer and the nurse agreed that 21 patients were mentally ill and that 54 were not. There was disagreement on only 11 cases.