title: Using structural neuroimaging to make quantitative predictions of symptom progression in individuals at ultra-high risk for psychosis.
abstract: Neuroimaging holds the promise that it may one day aid the clinical assessment of individual psychiatric patients. However, the vast majority of studies published so far have been based on average differences between groups, which do not permit accurate inferences at the level of the individual. We examined the potential of structural Magnetic Resonance Imaging (MRI) data for making accurate quantitative predictions about symptom progression in individuals at ultra-high risk for developing psychosis. Forty people at ultra-high risk for psychosis were scanned using structural MRI at first clinical presentation and assessed over a period of 2 years using the Positive and Negative Syndrome Scale. Using a multivariate machine learning method known as relevance vector regression (RVR), we examined the relationship between brain structure at first clinical presentation, characterized in terms of gray matter (GM) volume and cortical thickness (CT), and symptom progression at 2-year follow-up. The application of RVR to whole-brain CT MRI data allowed quantitative prediction of clinical scores with statistically significant accuracy (correlation = 0.34, p = 0.026; Mean Squared-Error = 249.63, p = 0.024). This prediction was informed by regions traditionally associated with schizophrenia, namely the right lateral and medial temporal cortex and the left insular cortex. In contrast, the application of RVR to GM volume did not allow prediction of symptom progression with statistically significant accuracy. These results provide proof-of-concept that it could be possible to use structural MRI to inform quantitative prediction of symptom progression in individuals at ultra-high risk of developing psychosis. This would enable clinicians to target those individuals at greatest need of preventative interventions thereby resulting in a more efficient use of health care resources.
authors: Department of Psychosis Studies, Institute of Psychiatry, King's College London , London , UK.
authors: Stefania
authors: S
authors: Tognin
authors: Department of Psychosis Studies, Institute of Psychiatry, King's College London , London , UK.
authors: William
authors: W
authors: Pettersson-Yeo
authors: Department of Psychosis Studies, Institute of Psychiatry, King's College London , London , UK.
authors: Isabel
authors: I
authors: Valli
authors: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London , London , UK.
authors: Chloe
authors: C
authors: Hutton
authors: Division of Experimental Medicine, Imperial College London , London , UK.
authors: James
authors: J
authors: Woolley
authors: Department of Psychosis Studies, Institute of Psychiatry, King's College London , London , UK.
authors: Paul
authors: P
authors: Allen
authors: Department of Psychosis Studies, Institute of Psychiatry, King's College London , London , UK.
authors: Philip
authors: P
authors: McGuire
authors: Department of Psychosis Studies, Institute of Psychiatry, King's College London , London , UK.
authors: Andrea
authors: A
authors: Mechelli
keywords: cortical thickness; magnetic resonance imaging; prediction; psychosis; relevance vector regression; symptom progression; ultra-high risk