Genetic Epidemiology, Translational Neurogenomics, Psychiatric Genetics and Statistical Genetics Laboratories investigate the pattern of disease in families, particularly identical and non-identical twins, to assess the relative importance of genes and environment in a variety of important health problems.
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PMID
42358081
TITLE
Can We Improve the Prediction of Early Onset Mania and Hypomania in the Community?
ABSTRACT
BACKGROUND
There is broad agreement that the onset of bipolar disorders (BD) can be predicted by using combined estimates of familial, genetic and clinical risk. However, there is a lack of consensus about the operationalisation of different risk attributes (e.g., symptoms vs. sub-threshold syndromes; disorder-specific polygenic risk scores [PRS] vs. multiple-disorder PRS dimensions) and their utility for predicting bipolar type 1 (BD-I) and 2 (BD-II). Likewise, analyses often fail to consider the optimal model for predicting outcomes where true cases will be in the minority.
METHODOLOGY
There is broad agreement that the onset of bipolar disorders (BD) can be predicted by using combined estimates of familial, genetic and clinical risk. However, there is a lack of consensus about the operationalisation of different risk attributes (e.g., symptoms vs. sub-threshold syndromes; disorder-specific polygenic risk scores [PRS] vs. multiple-disorder PRS dimensions) and their utility for predicting bipolar type 1 (BD-I) and 2 (BD-II). Likewise, analyses often fail to consider the optimal model for predicting outcomes where true cases will be in the minority. Proof of concept study employing an ensemble machine learning approach (Boosting) to develop models for classifying BD cases vs. non-cases using different combinations of risk attributes extracted from a database from a prospective longitudinal follow-up of twin and non-twin siblings in the peak age range for onset of major mental disorders.
RESULTS
There is broad agreement that the onset of bipolar disorders (BD) can be predicted by using combined estimates of familial, genetic and clinical risk. However, there is a lack of consensus about the operationalisation of different risk attributes (e.g., symptoms vs. sub-threshold syndromes; disorder-specific polygenic risk scores [PRS] vs. multiple-disorder PRS dimensions) and their utility for predicting bipolar type 1 (BD-I) and 2 (BD-II). Likewise, analyses often fail to consider the optimal model for predicting outcomes where true cases will be in the minority. Proof of concept study employing an ensemble machine learning approach (Boosting) to develop models for classifying BD cases vs. non-cases using different combinations of risk attributes extracted from a database from a prospective longitudinal follow-up of twin and non-twin siblings in the peak age range for onset of major mental disorders. Of 1473 participants (mean age 26.3; female = 866), 104 developed BD-I (n = 30) or BD-II (n = 74). The best performing Boosting classification had an overall area under the receiver operating curve (AUROC) of 85.1% (95% Confidence Intervals: 80%, 88%); correctly identifying 86.7% BD cases. Variables with greatest relative influence were, in rank order: depressive symptoms, psychotic symptoms, a BD-Schizophrenia PRS dimension, hypomanic symptoms, and family history of BD. The model accurately classified 89% of manic cases but only 68% of hypomanic cases.
CONCLUSIONS
There is broad agreement that the onset of bipolar disorders (BD) can be predicted by using combined estimates of familial, genetic and clinical risk. However, there is a lack of consensus about the operationalisation of different risk attributes (e.g., symptoms vs. sub-threshold syndromes; disorder-specific polygenic risk scores [PRS] vs. multiple-disorder PRS dimensions) and their utility for predicting bipolar type 1 (BD-I) and 2 (BD-II). Likewise, analyses often fail to consider the optimal model for predicting outcomes where true cases will be in the minority. Proof of concept study employing an ensemble machine learning approach (Boosting) to develop models for classifying BD cases vs. non-cases using different combinations of risk attributes extracted from a database from a prospective longitudinal follow-up of twin and non-twin siblings in the peak age range for onset of major mental disorders. Of 1473 participants (mean age 26.3; female = 866), 104 developed BD-I (n = 30) or BD-II (n = 74). The best performing Boosting classification had an overall area under the receiver operating curve (AUROC) of 85.1% (95% Confidence Intervals: 80%, 88%); correctly identifying 86.7% BD cases. Variables with greatest relative influence were, in rank order: depressive symptoms, psychotic symptoms, a BD-Schizophrenia PRS dimension, hypomanic symptoms, and family history of BD. The model accurately classified 89% of manic cases but only 68% of hypomanic cases. Improving the accurate prediction of BD onset would benefit from greater consensus regarding the operationalisation of known risk attributes and selection of analytic models that consider sample imbalances.
© 2026 The Author(s). Bipolar Disorders published by John Wiley & Sons Ltd.
DATE PUBLISHED
2026 Aug
HISTORY
PUBSTATUS PUBSTATUSDATE
revised 2026/05/25
received 2025/11/03
accepted 2026/06/08
medline 2026/06/27 07:10
pubmed 2026/06/26 06:38
entrez 2026/06/26 03:02
pmc-release 2026/06/26
AUTHORS
NAME COLLECTIVENAME LASTNAME FORENAME INITIALS AFFILIATION AFFILIATIONINFO
Scott J Scott Jan J Institute of Neuroscience, Newcastle University, Newcastle, UK.
Crouse JJ Crouse Jacob J JJ Brain and Mind Centre, The University of Sydney, Sydney, Australia.
Medland SE Medland Sarah E SE School of Psychology and Counselling, Queensland University of Technology, Brisbane, Queensland, Australia.
Mitchell BL Mitchell Brittany L BL Institute of Molecular Bioscience, The University of Queensland, Brisbane, Australia.
Gillespie NA Gillespie Nathan A NA Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia, USA.
Martin NG Martin Nicholas G NG Brain and Mental Health Program, QIMR Berghofer Institute of Medical Research, Brisbane, Australia.
Hickie IB Hickie Ian B IB Brain and Mind Centre, The University of Sydney, Sydney, Australia.
INVESTIGATORS
JOURNAL
VOLUME: 28
ISSUE: 5
TITLE: Bipolar disorders
ISOABBREVIATION: Bipolar Disord
YEAR: 2026
MONTH: Aug
DAY:
MEDLINEDATE:
SEASON:
CITEDMEDIUM: Internet
ISSN: 1399-5618
ISSNTYPE: Electronic
MEDLINE JOURNAL
MEDLINETA: Bipolar Disord
COUNTRY: Denmark
ISSNLINKING: 1398-5647
NLMUNIQUEID: 100883596
PUBLICATION TYPE
PUBLICATIONTYPE TEXT
Journal Article
Research Support, Non-U.S. Gov't
COMMENTS AND CORRECTIONS
GRANTS
GRANTID AGENCY COUNTRY
1031119 National Health and Medical Research Council
1049911 National Health and Medical Research Council
APP10499110 National Health and Medical Research Council
GENERAL NOTE
KEYWORDS
KEYWORD
bipolar disorder
boosting
family history
onset
polygenic scores
prediction
youth
MESH HEADINGS
DESCRIPTORNAME QUALIFIERNAME
Humans
Bipolar Disorder classification
Mania genetics
Female genetics
Male genetics
Age of Onset genetics
Genetic Risk Score genetics
Boosting Machine Learning Algorithms genetics
Predictive Learning Models genetics
Prediction Algorithms genetics
Classification Algorithms genetics
Adolescent genetics
SUPPLEMENTARY MESH
GENE SYMBOLS
CHEMICALS
OTHER ID's