title: Using clinical information to make individualized prognostic predictions in people at ultra high risk for psychosis.
abstract: Recent studies have reported an association between psychopathology and subsequent clinical and functional outcomes in people at ultra-high risk (UHR) for psychosis. This has led to the suggestion that psychopathological information could be used to make prognostic predictions in this population. However, because the current literature is based on inferences at group level, the translational value of the findings for everyday clinical practice is unclear. Here we examined whether psychopathological information could be used to make individualized predictions about clinical and functional outcomes in people at UHR. Participants included 416 people at UHR followed prospectively at the Personal Assessment and Crisis Evaluation (PACE) Clinic in Melbourne, Australia. The data were analysed using Support Vector Machine (SVM), a supervised machine learning technique that allows inferences at the individual level. SVM predicted transition to psychosis with a specificity of 60.6%, a sensitivity of 68.6% and an accuracy of 64.6% (p<0.001). In addition, SVM predicted functioning with a specificity of 62.5%, a sensitivity of 62.5% and an accuracy of 62.5% (p=0.008). Prediction of transition was driven by disorder of thought content, attenuated positive symptoms and functioning, whereas functioning was best predicted by attention disturbances, anhedonia-asociality and disorder of thought content. These results indicate that psychopathological information allows individualized prognostic predictions with statistically significant accuracy. However, this level of accuracy may not be sufficient for clinical translation in real-world clinical practice. Accuracy might be improved by combining psychopathological information with other types of data using a multivariate machine learning framework.
authors.affiliation: Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK. Electronic address: a.mechelli@kcl.ac.uk.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mechelli
authors.affiliation: Telethon Kids Institute, University of Western Australia, Subiaco, Western Australia 6008, Australia.
authors.forename: Ashleigh
authors.initials: A
authors.lastname: Lin
authors.affiliation: Department of Psychology, University of Birmingham, Birmingham, UK; Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne & Melbourne Health, Melbourne, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Wood
authors.affiliation: Orygen, The National Centre of Excellence in Youth Mental Health, Melbourne, Australia; The Centre for Youth Mental Health, The University of Melbourne, Melbourne, Australia.
authors.forename: Patrick
authors.initials: P
authors.lastname: McGorry
authors.affiliation: Orygen, The National Centre of Excellence in Youth Mental Health, Melbourne, Australia; The Centre for Youth Mental Health, The University of Melbourne, Melbourne, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Amminger
authors.affiliation: Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
authors.forename: Stefania
authors.initials: S
authors.lastname: Tognin
authors.affiliation: Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
authors.forename: Philip
authors.initials: P
authors.lastname: McGuire
authors.affiliation: Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Young
authors.affiliation: Orygen, The National Centre of Excellence in Youth Mental Health, Melbourne, Australia; The Centre for Youth Mental Health, The University of Melbourne, Melbourne, Australia.
authors.forename: Barnaby
authors.initials: B
authors.lastname: Nelson
authors.affiliation: Institute of Brain, Behaviour, and Mental Health, University of Manchester, Manchester, UK; Greater Manchester West NHS Mental Health Foundation Trust, Prestwich, Manchester, UK.
authors.forename: Alison
authors.initials: A
authors.lastname: Yung
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care / Q000379:methods* / Q000592:standards; D011379:Prognosis; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000628:therapy; D012680:Sensitivity and Specificity; D060388:Support Vector Machine / Q000592:standards; D014739:Victoria; D055815:Young Adult
keywords: Clinical outcome; Functional outcome; Psychosis; Support vector machine; Ultra-high risk