Introducing a Short Self-Report for the Assessment of DSM-5 Level of Personality Functioning for Personality Disorders: The Self and Interpersonal Functioning Scale

In the present study, we report on the development and validation of the Self and Interpersonal Functioning Scale (SIFS), a 24-item self-report questionnaire designed to assess the four core elements of personality pathology (Identity, Self-direction, Empathy, and Intimacy) from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Level of Personality Functioning for personality disorders. Participants from a community sample (n = 280) and patients from a specialized treatment facility for personality disorders (n = 106) were included in the validation sample. Overall, the SIFS showed sound psychometric properties. A second-order factor solution, which consisted of the four Level of Personality Functioning elements and an overarching personality pathology factor, showed the best fit indices. The four SIFS elements showed a well-differentiated and conceptually meaningful pattern of associations with related constructs. In light of these results, the SIFS should be considered as a promising, concise measure of Criterion A for clinical screening and research purposes. Its relative strengths and limitations in contrast with other existing self-report measures of Criterion A are discussed.