Sensitivity and specificity of a new bipolar spectrum diagnostic scale

To assess the sensitivity and specificity of a self-report questionnaire for bipolar disorder, the Bipolar Spectrum Diagnostic Scale (BSDS).

The BSDS was administered to 68 consecutive patients with bipolar illness and 27 consecutive patients with unipolar major depressive disorder. Created by Ronald Pies, it consists of a descriptive story that captures subtle features of bipolar illness, to which patients may assent on a sentence-by-sentence basis. BSDS scores were compared to clinicians' DSM-IV-based diagnoses.

Sensitivity of the BSDS was 0.76, approximately equal in bipolar I and II/NOS subjects (0.75 and 0.79, respectively). The BSDS identified 85% of unipolar-depressed patients as not having bipolar spectrum illness. A shift in the threshold of the BSDS resulted in a large increase in specificity (from 0.85 to 0.93), without a significant loss of sensitivity.

The BSDS was highly sensitive and specific for bipolar spectrum illness, especially with the amended threshold for positive diagnosis.