A clinically useful self-report measure of the DSM-5 mixed features specifier of major depressive disorder

Abstract

Background: To acknowledge the clinical significance of manic features in depressed patients, DSM-5 included criteria for a mixed features specifier for major depressive disorder (MDD). In the present report from the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project we modified our previously published depression scale to include a subscale assessing the DSM-5 mixed features specifier.

Methods: More than 1100 psychiatric outpatients with MDD or bipolar disorder completed the Clinically Useful Depression Outcome Scale (CUDOS) supplemented with questions for the DSM-5 mixed features specifier (CUDOS-M). To examine discriminant and convergent validity the patients were rated on clinician severity indices of depression, anxiety, agitation, and irritability. Discriminant and convergent validity was further examined in a subset of patients who completed other self-report symptom severity scales. Test-retest reliability was examined in a subset who completed the CUDOS-M twice. We compared CUDOS-M scores in patients with MDD, bipolar depression, and hypomania.

Results: The CUDOS-M subscale had high internal consistency and test-retest reliability, was more highly correlated with another self-report measure of mania than with measures of depression, anxiety, substance use problems, eating disorders, and anger, and was more highly correlated with clinician severity ratings of agitation and irritability than anxiety and depression. CUDOS-M scores were significantly higher in hypomanic patients than depressed patients, and patients with bipolar depression than patients with MDD.

Limitations: The study was cross-sectional, thus we did not examine whether the CUDOS-M detects emerging mixed symptoms when depressed patients are followed over time. Also, while we examined the correlation between the CUDOS-M and clinician ratings of agitation and irritability, we did not examine the association with a clinician measure of manic symptomatology such as the Young Mania Rating Scale

Conclusions: In the present study of a large sample of psychiatric outpatients, the CUDOS-M was a reliable and valid measure of the DSM-5 mixed features specifier for MDD.

Keywords: Bipolar disorder; DSM-5; Mixed features; Self-report.