Psychosis affects how people experience and interpret reality and can involve unusual beliefs and experiences, and difficulties with thinking and concentration.

Although Early Detection mental health services can identify people who are at increased risk of psychosis, predicting which of these individuals will later develop the disorder remains a major clinical challenge.

An international study, led by researchers from the University of Oxford’s Department of Psychiatry and Oxford Health NHS Foundation Trust (OHFT) investigated whether molecules called microRNAs could be used to improve this prediction. MicroRNAs normally regulate how our genes work and are present in the bloodstream.

In this study, researchers measured the levels of five microRNAs that had previously been associated with psychosis. They studied two large groups of people at high risk of developing psychosis, one in Europe and the other in North America. After providing a blood sample, the participants were followed for 2 years. Over that period, some of the group developed psychosis.

In both groups, the levels of the five microRNAs helped to distinguish between the people who later developed psychosis and those who did not.

These findings suggest that blood markers could be used to identify the individuals who are most likely to later develop psychosis. However, further research will be needed before these markers are ready for use in clinical practice.

Professor Philip McGuire

Senior author Philip McGuire, Professor of Psychiatry at the University of Oxford and Associate Director of Research & Development at OHFT, said:

“These findings have important implications for mental health care. At present, it is not possible to predict whether someone who is vulnerable to psychosis will, or will not go on to develop the disorder. This study has identified a new ‘biomarker’ for psychosis, a blood test that could allow us to predict whether an individual who is at risk will develop the disorder in the next few years. We think this test has the potential to eventually be used in clinical practice, because we found that it worked well in two large, independent samples of participants. The test could enhance the value of future preventive treatments for psychosis, as it could allow clinicians to offer preventive interventions to those who most need them”.

The paper, “Brain-enriched extracellular vesicle microRNAs could help to predict onset of psychosis in people at clinical high risk”, is available to read online in the current issue of World Psychiatry.