Psychometric Properties of the Mixed State Severity Index for Patients With Mood Disorder.

ABSTRACT:

Objective

This study aimed to develop a reliable and valid Mixed State Severity Index (MSSI) to assess mood instability in patients with mood disorders and determine cutoff scores.

Methods

Twenty-one items were selected based on Koukopoulos' criteria for mixed depressive episode, historically referred to as agitated depression, and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision mixed features criteria. The MSSI was administered to 242 patients (major depressive disorder [n=92], bipolar disorder [BD] I [n=78], and BD II [n=72]) and 726 controls.

Results

The MSSI demonstrated high internal consistency (α=0.78-0.90). Exploratory factor analysis revealed a stable four-factor structure. Based on receiver operating characteristic analysi

SUBMITTER: Myung W 

PROVIDER: S-EPMC12835643 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature