The Interpersonal Style Questionnaire (ISQ): factor structure and preliminary validity

Some clinical theories assuming a complexity-oriented perspective conceive personality as a processual phenomenon: through repeated experiences with others, some relational patterns emerge and gradually create a coherent sense of self. The Interpersonal Style Questionnaire (ISQ) has been designed according to these theories. Study 1 presented the preliminary validation of the ISQ factor structure. Italian adults (N = 547; 367 females) completed the ISQ and Ten Item Personality Measure (TIPI). Seven factors have been found using exploratory factor analysis, labeled based on item content: I. Dependent-Independent, II. Withdrawn-Sociable, III. Confident-Resigned, IV. Responsible-Impulsive, V. Ambitious-Modest, VI. Open-Stable and VII. Gregarious-Competitive. Study 2 cross-validated the seven factors using an independent sample (N = 506; 377 females) and Exploratory Structural Equation Modeling (ESEM). ISQ has been tested for concurrent validity using, International Personality Item Pool Representation of Big Five Measure, (IPIP-BFM-50); Mini Questionnaire of Personal Organization (MQPO); Reflective Function Questionnaire, RFQ; Relationship Questionnaire (RQ). The seven-factor model achieved close-fit test, and the ISQ items were found to measure the corresponding factors with sufficient reliability. Dependent-Independent and Confident-Resigned were associated with Neuroticism, Responsible-Impulsive with Conscientiousness, and Withdrawn-Sociable and Gregarious-Competitive with Agreeableness. Open-Stable and Ambitious-Modest were less strongly associated with the canonical Big-Five. The ISQ factors also showed significant correlations with the clinical scales, especially Dependent-Independent with RQ Anxious/ Self Model, RFQ Certainty about mental states, and MQPO Contextualized scores. In conclusion, the ISQ is a promising new questionnaire for assessing the interpersonal manifestations of personality with satisfactory validity and reliability.