Bipolar Inventory of Symptoms Scale Displays High Sensitivity, Low Specificity for Comorbid Anxiety Disorders

The Bipolar Inventory of Symptoms Scale (BISS) may be an effective screening tool for identifying co-occurring anxiety in patients with bipolar disorder, according to study data published in The Journal of Affective Disorders.

Investigators abstracted patient data from the Bipolar Clinical Health Outcomes Initiative in Comparative Effectiveness (CHOICE) study. The CHOICE study randomly assigned adult patients with bipolar disorder type I and type II (n=482) to adjunctive personalized therapy with either lithium or quetiapine for 6 months. Global illness severity was assessed using the Clinical Global Impressions – Bipolar Scale; mood symptoms and anxiety severity were captured with the BISS. Anxiety disorders were diagnosed with the Mini-International Neuropsychiatric Interview. Investigators examined the correlation between BISS anxiety domain score and anxiety diagnosis.

Among 482 study participants, 283 (59%) were women and 68% were diagnosed with bipolar I disorder. Patients had a mean (standard deviation) BISS anxiety score of 15.9 (8.2), and a majority (61%) were diagnosed with 1 or more anxiety disorder. At baseline, the following anxiety disorders were observed in patients: agoraphobia (37%), social phobia (25%), panic disorder (23%), generalized anxiety disorder (22%), posttraumatic stress disorder (12%), and obsessive-compulsive disorder (11%). Patients with higher anxiety at baseline had higher overall bipolar disorder severity, depressive episode severity, manic episode severity (P <.0001 for all), and an earlier age of bipolar disorder onset (P =.01). A single cutoff value of BISS anxiety displayed high sensitivity and low specificity for comorbid anxiety disorders; among 295 patients with any current anxiety disorder, 262 had a BISS anxiety score of at least 10 (87% sensitivity). However, in 187 patients without an anxiety disorder, just 73 had a BISS anxiety score below 10 (40% specificity).

Investigators recommended the BISS as a screening tool for comorbid anxiety disorders in patients with bipolar disorder. However, because of low specificity, the BISS may not be appropriate as a clinical assessment measure. The high BISS scores observed among patients without any anxiety disorder diagnosis may be of interest for future research.

Reference

Kinrys G, Bowden CL, Nierenberg AA, et al. Comorbid anxiety in bipolar CHOICE: insights from the bipolar inventory of symptoms scale. J Affect Disord. 2018;246:126-131.