A simple breath test could be used to diagnose and monitor somebody with schizophrenia, say scientists.

Research presented at the Royal College of Psychiatrists' annual meeting in Edinburgh showed analysing human breath can help with diagnosis.

Studies have shown that people with schizophrenia have higher levels of some of the gases contained in human breath compared with those who do not have the condition.

These gases include carbon disulphide, pentane, ethane and butane and the increased levels may be caused by the way their body breaks down fat. Work is underway to find out exactly why these differences occur.

There are nearly 400 different elements of human breath and studies have shown the presence of abnormal elements can be used to diagnose many diseases.

Developments in technology are enabling doctors to diagnose even more conditions through breath analysis.

'A useful aid'

But psychiatrists were told that subject to clinical trials, breath tests could become common practice in diagnosing schizophrenia.

Dr Marion Ross, a biochemist at the Highland Psychiatric Research Foundation, in Inverness, told delegates that results from trials of the test were promising.

"Diagnosis is always one of the big problems with schizophrenia. This is only preliminary research but we are getting some promising results."

She added that breath tests could, in the future, be used to monitor the condition and allow for drugs to be tailored exactly for the patient.

Approximately one per cent of the population develop schizophrenia during their lives, with both men and women equally affected.