A different approach toward screening for bipolar disorder: the prototype matching method

Most screening scales for psychiatric disorders consist of a series of questions about the signs and symptoms of the disorder of interest, and to determine whether a patient screens positive, the scores of the individual items are summed and the total score is compared with an empirically derived threshold. A problem with the score summation approach toward case identification on screening scales is that different studies may find that different thresholds are optimal for distinguishing cases from noncases. An alternative approach toward screening is the prototype matching approach, in which respondents are asked to indicate how well their clinical history matches the described prototype. In the present report from the Rhode Island Methods to Improve Diagnostic Assessment and Services project, we compared the symptom summation and prototype matching approaches toward screening for bipolar disorder in a large sample of psychiatric outpatients. Nine hundred sixty-one psychiatric outpatients were interviewed with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition and completed the Bipolar Spectrum Disorders Scale (BSDS). The BSDS is a unique screening scale consisting of a prototypic description of bipolar disorder. The respondent checks off which items in the prototypic paragraph describes them and also answers a single multiple-choice question at the end of the paragraph asking how well the paragraph describes them. The results of a receiver operating curve analysis found that the score summation and prototype matching approaches toward screening on the BSDS performed equally well. These findings provide preliminary evidence that an alternative approach toward psychiatric screening, the prototype matching approach, is as effective as the traditional score summation method. This raises the intriguing possibility of developing a combined screening scale/educational instrument that can be formatted as a brochure and thus placed in clinicians' waiting rooms, thereby facilitating use of the measure.