Objectives: The Mood Disorders Questionnaire (MDQ) has been the most widely studied screening questionnaire for bipolar disorder, though few studies have examined its performance in a heterogeneous sample of psychiatric outpatients. In the present report from the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project, we examined the operating characteristics of the MDQ in a large sample of psychiatric outpatients presenting for treatment.
Methods: A total of 534 psychiatric outpatients were interviewed with the Structured Clinical Interview for DSM-IV and asked to complete the MDQ. Missing data on the MDQ reduced the number of patients to 480, 10.4% (n = 52) of whom were diagnosed with bipolar disorder.
Results: Based on the scoring guidelines recommended by the developers of the MDQ, the sensitivity of the scale was only 63.5% for the entire group of bipolar patients. The specificity of the scale was 84.8%, and the positive and negative predictive values were 33.7% and 95.0%, respectively. When impairment was not required to define a case on the MDQ, then sensitivity increased to 75.0%, specificity dropped to 78.5%, positive predictive value was 29.8%, and negative predictive value was 96.3%.
Conclusions: In a large sample of psychiatric outpatients, we found that the MDQ, when scored according to the developers' recommendations, had inadequate sensitivity as a screening measure. After the threshold to determine MDQ caseness was lowered by not requiring moderate or severe impairment, the sensitivity of the scale increased, but specificity decreased, and positive predictive value remained below 30%. These results raise questions regarding the MDQ's utility in routine clinical practice.