Towards a Standard Psychometric Diagnostic Interview for Subjects at Ultra High Risk of Psychosis: CAARMS versus SIPS

Hindawi Publishing Corporation Psychiatry Journal Volume 2016, Article ID 7146341, 11 pages http://dx.doi.org/10.1155/2016/7146341 Research Article Towards a Standard Psychometric Diagnostic Interview for Subjects at Ultra High Risk of Psychosis: CAARMS versus SIPS P. Fusar-Poli,1,2 M. Cappucciati,1 G. Rutigliano,1 T. Y. Lee,3 Q. Beverly,4 I. Bonoldi,1,2 J. Lelli,5 S. J. Kaar,2 E. Gago,2 M. Rocchetti,1 R. Patel,1,2 V. Bhavsar,1,2 S. Tognin,1,2 S. Badger,1,2 M. Calem,1,2 K. Lim,3 J. S. Kwon,3 J. Perez,4,6 and P. McGuire1,2 1 Institute of Psychiatry Psychology and Neuroscience (IoPPN), King’s College London, London SE5 8AF, UK OASIS Service, South London and Maudsley NHS Foundation Trust, London SE11, UK 3 Department of Psychiatry, Seoul National University College of Medicine, Seoul 08826, Republic of Korea 4 Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge CB21 5HH, UK 5 Real-Time Systems Laboratory, Scuola Superiore Sant’Anna, 56124 Pisa, Italy 6 Department of Psychiatry, University of Cambridge, Cambridge CB2 0SZ, UK 2 Correspondence should be addressed to P. Fusar-Poli; Received 6 January 2016; Accepted 29 March 2016 Academic Editor: Lenin Pavon Copyright © 2016 P. Fusar-Poli et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Several psychometric instruments are available for the diagnostic interview of subjects at ultra high risk (UHR) of psychosis. Their diagnostic comparability is unknown. Methods. All referrals to the OASIS (London) or CAMEO (Cambridgeshire) UHR services from May 13 to Dec 14 were interviewed for a UHR state using both the CAARMS 12/2006 and the SIPS 5.0. Percent overall agreement, kappa, the McNemar-Bowker 𝜒2 test, equipercentile methods, and residual analyses were used to investigate diagnostic outcomes and symptoms severity or frequency. A conversion algorithm (CONVERT) was validated in an independent UHR sample from the Seoul Youth Clinic (Seoul). Results. There was overall substantial CAARMS-versus-SIPS agreement in the identification of UHR subjects (𝑛 = 212, percent overall agreement = 86%; kappa = 0.781, 95% CI from 0.684 to 0.878; McNemarBowker test = 0.069), with the exception of the brief limited intermittent psychotic symptoms (BLIPS) subgroup. Equipercentilelinking table linked symptoms severity and frequency across the CAARMS and SIPS. The conversion algorithm was validated in 93 UHR subjects, showing excellent diagnostic accuracy (CAARMS to SIPS: ROC area 0.929; SIPS to CAARMS: ROC area 0.903). Conclusions. This study provides initial comparability data between CAARMS and SIPS and will inform ongoing multicentre studies and clinical guidelines for the UHR psychometric diagnostic interview. “The comparability of measurements made in differing circumstances by different methods and investigators is a fundamental precondition for all of science” Dorans and Holland (2000) 1. Introduction The development of psychometric tools to prospectively identify subjects at ultra high clinical risk (UHR hereafter) of psychosis has allowed preventative screening [1], diagnosis [2], and interventions [3] to be feasible in psychiatry. In 1991, Jackson and McGorry were the first to initiate reliability studies to psychometrically assess first-episode subjects via a semistructured interview in order to ascertain the presence of prodromal symptoms [4]. On the basis of their results, in 1995 Yung and colleagues set up the first clinical service for UHR individuals and conceived the first comprehensive UHR psychometric instrument [5]. The Comprehensive Assessment of At-Risk Mental States (CAARMS hereafter) was developed at the Personal Assessment and Crisis Evaluation (PACE) Clinic in Melbourne [6] and has been widely used in Australia, Asia, and Europe to interview for “At-Risk Mental State, ARMS,” criteria. Their pivotal work resulted 2 in the formulation of three UHR criteria: attenuated psychotic symptoms (APS hereafter), brief limited intermittent psychotic symptoms (BLIPS hereafter), and trait vulnerability plus a marked decline in psychosocial functioning (Genetic Risk and Deterioration syndrome: GRD hereafter). A few years later, in 1999, based on these criteria, Miller et al. (1999) [7] developed a similar psychometric instrument for quantitatively rating symptoms in patients at UHR of psychosis [8], in the Prevention through Risk Identification, Management and Education (PRIME) Clinic in New Haven (USA): the Structured Interview for Psychosis-Risk Syndrome (SIPS hereafter) [8] (for a detailed genealogy of the CAARMS and SIPS see [9, 10]). The CAARMS and the SIPS address the same construct and use similar criteria, and they can deliver comparable positive predictive values over follow-up time [11, 12]. However, their operationalization differs [10], with substantial changes over different versions of the instruments [10]. Operationalization differences include disparity in psychopathological definitions of the APS, time and frequency criteria, functional decline criterion, BLIPS criteria, assessment of comorbidities, and substance misuse (see Tables 1 and 2 and eTable 1 (in Supplementary Material available online at http://dx.doi.org/10.1155/2016/7146341) for a detailed comparison of CAARMS 12/2006 and SIPS 5.0). The resulting overall weight of similarities and differences between the two instruments on UHR identification is unknown. Psychometric diagnostic uncertainty questions validity of the UHR diagnostic interview, creating inconsistencies between clinicians or researchers and misunderstandings in patients [13]. Comparability of current clinical, neurobiological, cognitive, and therapeutic UHR research findings may be also questionable and compromised, with the risk of “a profusion of statistically significant, but minimally differentiating” [14] results of limited clinical utility. Psychometric uncertainty may significantly impact the development of future large-scale UHR multicentre studies, by amplifying heterogeneity across individual sites. These concerns and speculations have never been tested empirically. To resolve the “current confusion” [13], research studies allowing “a thorough evaluation of the comparability of samples” [13] have been urgently advocated [10, 15]. We present here the first study addressing the psychometric comparability of the CAARMS 12/2006 [16] versus SIPS 5.0 [8]. Our principal aim was to test if the CAARMS 12/2006 and the SIPS 5.0 can equally identify UHR subjects in a large pool of individuals referred to high-risk services for potential UHR symptoms. Our second aim was to qualitatively investigate potential discrepancies and to link the severity and frequency of symptoms with equipercentile-linking tables. Our third aim was to develop a pragmatic algorithm to convert individual cases across the two ins (...truncated)