Validation of the Inventory of Interpersonal Problems (IIP-64): a comparison of Swedish female outpatients with anorexia nervosa or bulimia nervosa and controls.
The aim of the study was to explore the psychometric properties of the Inventory of Interpersonal Problems (IIP-64) and to compare levels of interpersonal distress in Swedish female outpatients with anorexia nervosa or bulimia nervosa with age- and gender-matched controls.
Totally, 401 participants were included; anorexia nervosa (n?=?74), bulimia nervosa (n?=?85) and controls (n?=?242). All participants completed the IIP-64. The eating disorder (ED) patients also filled out the Eating Disorder Inventory-2/3 (EDI).
Internal consistency of IIP-64 was acceptable to high. Principal component analyses with varimax rotation of the IIP-64 subscales confirmed the circumplex structure with two underlying orthogonal dimensions; affiliation and dominance. Significant correlations between EDI-3 composite scales ineffectiveness and interpersonal problems and IIP-64 were found. ED patients reported higher levels of interpersonal distress than controls on all but one subscale (intrusive/needy).
IIP-64 can be considered to have acceptable to good reliability and validity in a Swedish ED sample. IIP-64 can be a useful complement in assessment of interpersonal problems in ED.