Onset of psychosis could be predicted by brain scans
For the first time, researchers at the Institute of Psychiatry at King’s College London have shown that increased levels of dopamine in the brain precede the onset of psychosis. The findings suggest that brain scans could be used as a predictive test for psychosis.
Whilst there is previous evidence that levels of dopamine are elevated in the brains of patients who already suffer from psychosis, there has been little known about whether these levels are altered prior to the first episode of the illness. The study, published in the American Journal of Psychiatry, followed 30 individuals at ultra-high risk of psychosis over a period of 3 years. Ultra-high risk individuals are characterised as those who will develop a psychotic illness within 2 years.
Dr Oliver Howes, lead author of the study at the Institute of Psychiatry, King’s College London says: ‘Psychotic illnesses such as schizophrenia are one of the top ten health problems in young adults worldwide. The holy-grail is to find a way of preventing these devastating illnesses before they start. Our finding that dopamine function is elevated in people who go on to develop psychotic illnesses is an important clue as to what causes them.’
The researchers used PET brain scans to measure participants’ capacity to make dopamine. Dopamine function was more elevated in the people who went on to develop psychotic illness, such as schizophrenia, than health people or those who did not develop psychosis. The findings also show that higher dopamine function is associated with more severe symptoms in those who developed psychosis.
Dr Howes adds: ‘Future treatments could target this part of the brain’s dopamine system to prevent the full development of the illness. As roughly 1 in 10 people with schizophrenia die from suicide, predominantly in the first few years after the illness starts, a treatment that prevents the full illness could save many lives as well as alleviating suffering.’
Dr Howes continues: ‘Our findings show that there was no change in the dopamine function in patients who experienced psychiatric problems but got better later on. This suggests that the elevated level of dopamine is specific to the latter development of psychosis and we are looking to see if the scan can be used as a predictive test.’
The image shows a PET scan of the brain taken from the side. The red indicates high levels of dopamine function, and the green indicates low levels. The image is accredited to Dr Oliver Howes.
The research was funded by the Medical research Council (MRC) UK and the National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) for Mental Health.
Full paper: Howes O. et al. ‘Dopamine synthesis capacity before onset of psychosis: a prospective [18F]-DOPA PET imaging study’, American Journal of Psychiatry (doi: 10.1176/appi.ajp.2011.1101016)