Factor Structure of the Persian Version of the Leeds Dependence Questionnaire: An Exploratory Factor Analysis Publisher

Summary: Can one scale capture substance dependence? A psychometric study supports a single-factor structure for the Persian Leeds questionnaire, aiding severity assessment. #Addiction #Psychometrics

Massah O ; Rafiey H ; Radfar S R ; Farhoudian A
Source: Iranian Rehabilitation Journal Published:2026

Abstract

Objectives: The Leeds dependence questionnaire (LDQ) is a brief instrument designed to assess the severity of psychological dependence across substances for treatment and rehabilitation programs. Although the Persian version has previously shown good reliability and validity, its factorial structure has not been examined independently. This study aimed to investigate the factor structure of the Persian version of the LDQ among Iranian individuals with substance use disorders. Methods: This study was a secondary psychometric analysis of data from 170 treatment-seeking individuals with substance use disorders who completed the Persian LDQ. Descriptive statistics, item intercorrelations, Kaiser-Meyer-Olkin (KMO) measure, Bartlett's test of sphericity, and exploratory factor analysis using principal axis factoring were performed. Both the scree plot and the parallel analysis supported a one-factor solution. Results: The data were suitable for factor analysis (KMO=0.898; Bartlett's test χ^2=606.514, df=45, P<0.001). All items showed acceptable measures of sampling adequacy. The first eigenvalue was 4.669, accounting for 46.687 of the variance, whereas the second and third eigenvalues were below 1. In the parallel analysis, only the first observed eigenvalue exceeded the corresponding random eigenvalue, supporting retention of a single factor. Item 8 showed the weakest communality and the most distinct loading pattern in the exploratory extraction. Discussion: The Persian LDQ retains the essentially unidimensional structure of the original instrument and can be used as a valid measure of dependence severity in Iranian clinical and research settings. Copyright © 2026 The Author(s); This is an open access article distributed under the terms of the Creative Commons Attribution License (CC-BY-NC 4.0: https://creativecommons.org/licenses/by-nc/4.0/legalcode.en), which permits use, distribution, and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes