Translation and psychometric evaluation of the Persian version of the Cambridge Friendship Questionnaire in patients with schizophrenia

Background The Cambridge Friendship Questionnaire (FQ) was used to evaluate the extent to which participants enjoy close relationships and value interacting with friends. This study aimed to assess the psychometric properties of the FQ in patients with schizophrenia. Methods A cross-sectional study was conducted on 175 patients with schizophrenia who were selected from Shahid Beheshti Hospital and Golestan Salamat Center, Kerman. Data were collected via the Persian version of the FQ and the Relationships with Friends and Peers Questionnaire. The Persian FQ was evaluated for construct and content and criterion validity, internal consistency (Cronbach's alpha), and test-retest reliability. The data were analyzed via SPSS version 26 and Lisrel version 8.8 software. Results The Persian version of the FQ exhibited acceptable internal consistency (Cronbach's alpha = 0.649). There was a direct and significant correlation between the average scores of the two Cambridge friendship questionnaires and the scores of the relationships with friends and peers questionnaire (P = 0.028, r = 0.310). None of the goodness of fit indices were within the acceptance range, indicating that the construct validity of the single-factor model of the Persian version of the Cambridge Friendship Questionnaire was not confirmed. Conclusion The Persian translation of the FQ score demonstrated acceptable psychometric properties, in terms of reliability and concurrent validity but its construct validity needs to be investigated in other populations of patients with schizophrenia.