The Observer-Rated Scale for Mania (ORSM): development, psychometric properties and utility

BackgroundThe diagnosis of mania largely depends on the quality of information the physician is provided with. Often, the patient cannot give an accurate account of the symptom development and thus information from relatives and friends is required. No systematic rating instrument is available, however, to facilitate this.ObjectiveIn this study, the psychometric properties of the 49-item Observer-Rated Scale for Mania (ORSM) are reported.MethodsThe scale was used in 113 inpatients and the following psychometric aspects were assessed: reliability, test–retest reliability, construct validity (factor analysis, discriminant analysis, comparison of means), extreme-group validity, prognostic validity, sensitivity, specificity, positive and negative predictive values.ResultsThe ORSM proved highly valid and reliable. Factor analysis revealed three factors which were labelled euphoric mania, instable mania and psychotic mania.ConclusionThe ORSM is a useful instrument to help non-professionals who are in regular contact with the patient diagnosed a manic/mixed episode. It thus complements existing rating scales for mania, which are either designed for professionals or are self-rating instruments.