Assessing interpersonal fusion: reliability and validity of a new DSI fusion with others subscale.

The Differentiation of Self Inventory (DSI) is a multidimensional measure of differentiation consisting of four subscales focusing on adults (ages 25+), and their significant relationships, including current relationships with family of origin. Although the DSI full scale and three of its subscales are theoretically and psychometrically sound, the Fusion with Others (FO) subscale is lacking. Therefore, responses of 225 adults were used to revise the FO subscale. Results yielded a 12-item, revised FO subscale with improved internal consistency reliability and construct validity. Greater fusion with others was associated with greater spousal fusion and dimensions of adult attachment insecurity. Implications for Bowen theory and suggestions for future research with the DSI-R are discussed.