Factors associated with false positives in MDQ screening for bipolar disorder: Insight into the construct validity of the scale

Abstract

BackgroundIdentifying bipolar patients in the first phases of the illness is essential to establish adequate treatment. The goal of this study was to examine the discriminant ability of the Mood Disorders Questionnaire (MDQ) in recognizing bipolar patients referred to a tertiary care structure. MethodsBetween 2006 and 2012, we assessed 843 individuals referred to the Mood Disorders Program by family physicians in the community. The Structured Clinical Interview for DSM-IV-TR (SCID) was used to assess diagnoses. A nurse collected the information about lifetime symptoms of (hypo)mania in 759 individuals using the MDQ. Univariate chi-square test and logistic regression were used for the statistical analysis. ResultsOverall, 86% of the sample had a current anxiety or depressive disorder. When compared to the diagnoses formulated through the SCID, the sensitivity of the MDQ was 75.0%, the specificity was 74%, the positive predictive value was 55%, and the negative predictive value was 88%. Among non-bipolar patients, current post-traumatic stress disorder, borderline personality disorder, current or early remission substance use disorder, and the history of childhood abuse were independently associated with false positive screening using the MDQ. LimitationsIndividuals with current substance use disorders were under-represented, whether or not the patients were aware of their diagnosis of bipolar disorder was not recorded, and the history of childhood abuse was collected based on an open interview. ConclusionsThe self-rated measure of the symptoms listed by the MDQ seems to measure a dimension shared by both bipolar disorder and other conditions characterized by affective instability and impulsivity.