The positive and negative suicide ideation inventory: development and validation.

We conducted two studies to develop and validate a brief self-report measure for assessing the frequency of positive and negative thoughts related to suicidal behavior. Items on this new measure, the Positive and Negative Suicide Ideation inventory, were generated by undergraduates. In Study 1, we administered a 20-item version of the inventory to 150 male and 300 female undergraduates and conducted an exploratory principal axis factor analysis with varimax rotation. Two factors, Positive Ideation and Negative Ideation, were retained. In Study 2, we conducted a confirmatory factor analysis to validate the fit of the one-factor and the oblique two-factor models to data from another sample of 84 men and 202 women. The oblique two-factor model provided an excellent fit to the sample data. We also examined preliminary evidence of concurrent and predictive validity. Over-all, these findings suggested that the inventory is a well-developed self-report measure for assessing the frequency of positive and negative thoughts related to suicidal behavior.