Development and validation of a new scale to measure chronic suicidal ideation: The Chronic Suicidal Ideation Inventory-5 (CSI-5)

Objective: Little is known about characteristics that differentiate acute from chronic suicidal ideation. Studies have been hampered by the lack of a formal operational definition or measurement tool for chronic suicidal ideation (CSI). We sought to adapt a standardized measure of obsessive-compulsive thinking to rate chronic suicidal ideation in a mood disorder inpatient cohort. Method: We devised a novel self-report instrument, based on constructs related to obsessive-compulsive thinking and the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), as applied to preoccupations with suicidal thoughts and their persistence over 24 months in a previously described cohort of 97 inpatients with mood disorder. Exploratory factor analysis and principal components analysis were used to establish the factor structure of the instrument, and Cronbach's alpha and McDonald's omega were calculated to determine internal consistency of the scale. Results: Significant Pearson correlations with individual scale items and total CSI-5 scores were evident in relation to the 2-, 6-, 12- and 24-month periods preceding the index hospitalization. A one-factor solution explained 75% of the variance in total CSI-5 scores. Cronbach's alpha was 0.914, and McDonalds's omega was 0.916. CSI-5 scores were not significantly associated with current depression severity scores or actual past suicide attempts. Conclusions: This 5-item adaptation of Y-BOCS-type questions provides an internally consistent and reliable assessment of chronic suicidal ideation in patients with mood disorder. The integrated assessment of time occupied by suicidal thoughts, activity interference, associated distress, efforts to resist suicidal thoughts, and degree of control over suicidal thinking provides a cohesive framework for understanding chronic suicidal ideation.