Resumen
The Alda score is commonly used to quantify lithium responsiveness in bipolar disorder. Most often, this score is dichotomized into “responder” and “non-responder” categories, respectively. This practice is often criticized as inappropriate, since continuous variables are thought to invariably be “more informative” than their dichotomizations. We therefore investigated the degree of informativeness across raw and dichotomized versions of the Alda score, using data from a published study of the scale’s inter-rater reliability (n = 59 raters of 12 standardized vignettes each). After learning a generative model for the relationship between observed and ground truth scores (the latter defined by a consensus rating of the 12 vignettes), we show that the dichotomized scale is more robust to inter-rater disagreement than the raw 0-10 scale. Further theoretical analysis shows that when a measure’s reliability is stronger at one extreme of the continuum—a scenario which has received little-to-no statistical attention, but which likely occurs for the Alda score ≥ 7—dichotomization of a continuous variable may be more informative concerning its ground truth value, particularly in the presence of noise. Our study suggests that research employing the Alda score of lithium responsiveness should continue using the dichotomous definition, particularly when data are sampled across multiple raters.
Idioma original | English |
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Número de artículo | e0225353 |
Publicación | PLoS One |
Volumen | 15 |
N.º | 1 |
DOI | |
Estado | Published - ene. 1 2020 |
Nota bibliográfica
Funding Information:Genome Canada (MA, AN; https://www. genomecanada.ca), Dalhousie Department of Psychiatry Research Fund (MA, AN; https:// medicine.dal.ca/departments/department-sites/ psychiatry.html), Canadian Institutes of Health Research #64410 (MA; http://www.cihr-irsc.gc.ca), Natural Science and Engineering Research Council of Canada (TT; https://www.nserc-crsng.gc.ca), Nova Scotia Health Research Foundation Scotia Scholars Graduate Scholarship (AN; https://nshrf. ca), Killam Postgraduate Scholarship (AN; http:// www.killamlaureates.ca) and Dalhousie Medical Research Foundation and the Lindsay family (AN and MA). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors wish to acknowledge those members of the Consortium on Lithium Genetics (ConLiGen) who contributed ratings for the vignettes herein: Mirko Manchia, Raffaella Ardau, Jean-Michel Aubry, Lena Backlund, Claudio E.M. Banzato, Bernhard T. Baune, Frank Bellivier, Susanne Bengesser, Clara Brichant-Petitjean, Elise Bui, Cynthia V. Calkin, Andrew Tai Ann Cheng, Caterina Chillotti, Scott Clark, Piotr M. Czerski, Clarissa Dantas, Maria Del Zompo, J. Raymond DePaulo, Bruno Etain, Peter Falkai, Louise Frisén, Mark A. Frye, Jan Fullerton, Sébastien Gard, Julie Garnham, Fernando S. Goes, Paul Grof, Oliver Gruber, Ryota Hashimoto, Joanna Hauser, Rebecca Hoban, Stéphane Jamain, Jean-Pierre Kahn, Layla Kassem, Tadafumi Kato, John R. Kelsoe, Sarah Kittel-Schneider, Sebastian Kliwicki, Po-Hsiu Kuo, Ichiro Kusumi, Gonzalo Laje, Catharina Lavebratt, Marion Leboyer, Susan G. Leckband, Carlos A. López Jaramillo, Mario Maj, Alain Malafosse, Lina Martinsson, Takuya Masui, Philip B. Mitchell, Frank Mondimore, Palmiero Monteleone, Audrey Nallet, Maria Neuner, Tomás Novák, Claire O’Donovan, Urban Ösby, Norio Ozaki, Roy H. Perlis, Andrea Pfennig, James B. Potash, Daniela Reich-Erkelenz, Andreas Reif, Eva Reininghaus, Sara Richardson, Janusz K. Rybakowski31, Martin Schalling, Peter R. Schofield, Oliver K. Schubert, Barbara Schweizer, Florian Seemüller, Maria Grigoroiu-Serbanescu, Giovanni Severino, Lisa R. Seymour, Claire Slaney, Jordan W. Smoller, Alessio Squassina, Thomas Stamm, Pavla Stopkova, Sarah K. Tighe, Alfonso Tortorella, Adam Wright, David Zilles, Michael Bauer, Marcella Rietschel, and Thomas G. Schulze.
Publisher Copyright:
© 2020 Nunes et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
ASJC Scopus Subject Areas
- General
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't