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Monahan PO, Stump T, Coryell WH, Harezlak J, Marcoulides GA, Liu H, Steeger CM, Mitchell PB, Wilcox HC, Hulvershorn LA, Glowinski AL, Iyer-Eimerbrink PA, McInnis M, Nurnberger JI. Confirmatory test of two factors and four subtypes of bipolar disorder based on lifetime psychiatric co-morbidity. Psychol Med 2015; 45:2181-2196. [PMID: 25823794 DOI: 10.1017/s0033291715000185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND The first aim was to use confirmatory factor analysis (CFA) to test a hypothesis that two factors (internalizing and externalizing) account for lifetime co-morbid DSM-IV diagnoses among adults with bipolar I (BPI) disorder. The second aim was to use confirmatory latent class analysis (CLCA) to test the hypothesis that four clinical subtypes are detectible: pure BPI; BPI plus internalizing disorders only; BPI plus externalizing disorders only; and BPI plus internalizing and externalizing disorders. METHOD A cohort of 699 multiplex BPI families was studied, ascertained and assessed (1998-2003) by the National Institute of Mental Health Genetics Initiative Bipolar Consortium: 1156 with BPI disorder (504 adult probands; 594 first-degree relatives; and 58 more distant relatives) and 563 first-degree relatives without BPI. Best-estimate consensus DSM-IV diagnoses were based on structured interviews, family history and medical records. MPLUS software was used for CFA and CLCA. RESULTS The two-factor CFA model fit the data very well, and could not be improved by adding or removing paths. The four-class CLCA model fit better than exploratory LCA models or post-hoc-modified CLCA models. The two factors and four classes were associated with distinctive clinical course and severity variables, adjusted for proband gender. Co-morbidity, especially more than one internalizing and/or externalizing disorder, was associated with a more severe and complicated course of illness. The four classes demonstrated significant familial aggregation, adjusted for gender and age of relatives. CONCLUSIONS The BPI two-factor and four-cluster hypotheses demonstrated substantial confirmatory support. These models may be useful for subtyping BPI disorders, predicting course of illness and refining the phenotype in genetic studies.
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Affiliation(s)
- P O Monahan
- Department of Biostatistics,Indiana University School of Medicine,Indianapolis,IN,USA
| | - T Stump
- Department of Biostatistics,Indiana University School of Medicine,Indianapolis,IN,USA
| | - W H Coryell
- Department of Psychiatry,Roy J. and Lucille A. Carver College of Medicine,University of Iowa,Iowa City,IA,USA
| | - J Harezlak
- Department of Biostatistics,Indiana University School of Medicine,Indianapolis,IN,USA
| | - G A Marcoulides
- Research Methods & Statistics Program,Graduate School of Education,University of California-Riverside,Riverside,CA,USA
| | - H Liu
- Department of Biostatistics,Indiana University School of Medicine,Indianapolis,IN,USA
| | - C M Steeger
- Department of Psychology,College of Arts and Letters,University of Notre Dame,Notre Dame,IN,USA
| | - P B Mitchell
- School of Psychiatry,University of New South Wales,Sydney,NSW,Australia
| | - H C Wilcox
- Department of Psychiatry and Behavioral Sciences,Johns Hopkins School of Medicine,Baltimore,MD,USA
| | - L A Hulvershorn
- Department of Psychiatry,Indiana University School of Medicine,Indianapolis,IN,USA
| | - A L Glowinski
- Department of Psychiatry,Washington University School of Medicine,St Louis,MO,USA
| | - P A Iyer-Eimerbrink
- Department of Psychiatry,Indiana University School of Medicine,Indianapolis,IN,USA
| | - M McInnis
- Department of Psychiatry,School of Medicine,University of Michigan,Ann Arbor,MI,USA
| | - J I Nurnberger
- Department of Psychiatry,Indiana University School of Medicine,Indianapolis,IN,USA
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