Background: This study aims to replicate the sensitivity and specificity of the Mood Disorder Questionnaire (MDQ) for bipolar disorder and assess the impact of insight on the MDQ's sensitivity. Unlike prior telephone-based validation, this is the first clinical study to assess the validity of the MDQ.
Methods: 37 consecutive patients with bipolar spectrum illness received the MDQ, as well as 36 consecutive patients with unipolar depression. MDQ diagnoses were compared to DSM-IV-based SCID diagnoses. A total of 16 bipolar patients also received the Scale to Assess Unawareness of Mental Disorder (SUMD) to measure insight.
Results: Overall sensitivity for the MDQ was 0.58, higher in bipolar I disorder (0.69) than in bipolar II/NOS (0.30, P=0.06). The sample was highly insightful, but the two patients with lowest insight both had false negative screens. Patients' low ratings of severity of mania (question 3 of the MDQ) explained almost half of all false negative results. Specificity was 0.67.
Conclusions: The MDQ demonstrates good sensitivity in insightful patients with bipolar I disorder, but may be less useful in patients with impaired insight or milder bipolar spectrum conditions.