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.