Validity and reliability of the COgnitive Complaints in Bipolar disorder Rating Assessment (COBRA) in Italian bipolar patients.

Abstract

Background: Although bipolar disorder (BD) and cognitive impairment are straightly connected, limited tools exist to capture the patient's perspective on cognitive decline and its impact on this disorder. The aims of the study are: 1) to assess the reliability and validity of the Italian version of a brief self-report scale (COgnitive Complaints in Bipolar disorder Rating Assessment - COBRA) among euthymic bipolar patients; 2) to investigate the relationship between the self-report scale, COBRA, the objective neurocognitive measure Screen for Cognitive Impairment in Psychiatry (SCIP), and the course of illness in BD.

Methods: Western all-white sample (n=216) included 108 BD patients and 108 healthy matched controls. The psychometric properties of the COBRA (e.g., internal consistency, retest reliability, discriminative validity, factorial analysis, ROC curve and feasibility) were analyzed. A screening neuropsychological battery was used for objective cognitive assessment.

Results: The Italian version of the COBRA (COBRA-I) had a high internal consistency (Cronbach's alpha= 0.852) and retest reliability (ICC=0.848). Factor analysis validated the one-factor model, and the cut-off value was obtained with a score of 10.5. BD patients experienced greater cognitive complaints compared to control group suggesting a discriminative validity of the instrument. No significant correlation was found between COBRA and SCIP in the patients group. Higher COBRA scores were associated with BD type II, life-time hypomanic episodes and number of total episodes.

Conclusions: The study proved the validity of the COBRA-I as a simple and reliable self-report instrument for screening or monitoring cognitive complaints in adult patients with BD.