Influential Relationship Questionnaire (IRQ): psychometric characteristics of an abbreviated Spanish version.

Background: The relevance of family relationships in the outcome of various disorders has been highlighted from different domains. Specifically, empirical studies on the relationship between the outcome of schizophrenia and various affective dimensions of family relationships have allowed the identification of particularly relevant aspects: criticism, hostility, and over-protection.

Aims: The present study aims to adapt and validate an abbreviated Spanish version of the Influential Relationship Questionnaire (IRQ), an instrument that measures the patient's own perception of the affective dimensions of family relationships.

Method: Participants were 188 patients (63.8% male) of the Public Health Service in Andalusia (Spain) with a diagnosis of schizophrenia or a related disorder. One hundred and thirty-six participants provided data related to both father and mother, and 52 only related to mother or father, so the analyses were carried out with a total of 324 questionnaires. Simultaneously, in 130 participants, the Perceived Criticism Scale was applied, and in 50 cases, relatives were asked to complete the Family Attitudes Scale.

Results: Principal component analysis allowed for the identification of four factors that explained 61.53% of the total variance (criticism, over-protection, restriction, and care). The values of Cronbach's alpha coefficient, as well as the omega coefficient, showed high consistency. The temporal reliability for an interval of 3 months was high. The correlations between the IRQ dimensions and the other variables included in the study were significant and in the expected direction.

Conclusions: The results support the reliability and validity of the abbreviated version of the IRQ.