Psychometric properties of the Spanish version of the 12-item Interpersonal Needs Questionnaire in fibromyalgia syndrome patients

According to the interpersonal theory of suicide, thwarted belongingness and perceived burdensomeness are key elements in the development of suicidal ideation. The Interpersonal Needs Questionnaire (INQ) was developed to assess the degree of frustration of these two interpersonal needs related to suicidal ideation. This study aims to analyze the psychometrics properties of a Spanish adaptation of INQ-12 in fibromyalgia patients. Exploratory factor analysis (n = 180) and confirmatory factor analysis (n = 179) were performed in two randomly selected subsamples. The first analysis leads to the elimination of two items, whereas the second one confirmed the fit of the proposed two-factor structure. The reliability estimated using the Cronbach's alpha coefficient and the Spearman-Brown coefficient was adequate. To obtain further validity evidence based on the relationship with other variables three variables were used. Moreover, a control group (n = 99) was used to contrast the means of INQ scores as evidence of validity based on differential scores. These findings support the usefulness of the Spanish version of the INQ-10 for assessing the degree of frustration of these interpersonal needs in patients with fibromyalgia.