Development of the Bipolar Inventory of Symptoms Scale Bowden CL, Singh V, Thompson P, Gonzalez JM, Katz MM, Dahl M, Prihoda TJ, Chang X. Development of the Bipolar Inventory of Symptoms Scale. Objective: Most rating scales for bipolar disorders (BDs) do not encompass the spectrum of symptomatology now established as characterizing the illness. We report the rationale, format, reliability and initial validity studies of the Bipolar Inventory of Symptoms Scale (BISS), a 44-item scale designed to encompass the spectrum of behavioral disturbances in BDs. Method: Structured video interviews of 20 patients representing four bipolar syndromal subtypes were rated by nine raters. Results: Generally, high inter-rater reliability and internal consistency were established for the depression and mania subscales and the BISS total score. The BISS discriminated across subtypes of bipolar patients with depressed, manic/hypomanic, mixed manic or recovered status. Conclusion: The BISS has adequate reliability, concurrent validity and is capable of discriminating between bipolar subtypes. It also provides a comprehensive scale to assess discrete behavioral components of BD. C. L. Bowden, V. Singh, P. Thompson, J. M. Gonzalez, M. M. Katz, M. Dahl, T. J. Prihoda, X. Chang Department of Psychiatry, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA Key words: bipolar; assessment; rating scales; depression; mania Charles L. Bowden, MD, 7703 Floyd Curl Drive (Mail Code 7792), San Antonio, TX 78229-3900, USA. E-mail: bowdenc@uthscsa.edu Accepted for publication November 2, 2006 Significant outcome • A structured interview and rating scale encompassing the spectrum of bipolar symptomatology has been developed to facilitate clinical and pathophysiological studies on bipolar disorders. Limitation • Results are limited to an initial small but diversified sample. The most severely ill bipolar patients are difficult to enroll with informed consent. Further psychometric characterization is in progress. Introduction Rating scales commonly utilized to quantitate manic and depressive symptomatology in bipolar disorders (BDs) have limitations reviewed elsewhere (1–4). Although adequate for total scores for manic and depressive symptoms, most scales are limited by insufficient number of items to identify components of symptomatology subsequently established in BDs (5–7). Most scales were developed prior to the evidence of centrality of anxiety, impulsivity and mood instability in BD and the common occurrence of mixed states (8, 9). None provide a profile of the major components of the disorder. Aims of the study We report the reliability and preliminary validity studies of the Bipolar Inventory of Symptoms Scale (BISS), designed to comprehensively assess and quantitate the symptomatology of BDs, inclu- ding bipolar II and spectrum patients, and to provide a sensitive instrument for the detection of treatment effects. Acta Psychiatr Scand 2007: 116: 189–194 All rights reserved DOI: 10.1111/j.1600-0447.2006.00955.x Copyright Ó 2006 The Authors Journal Compilation Ó 2006 Blackwell Munksgaard ACTA PSYCHIATRICA SCANDINAVICA 189