Satisfaction With Methadone as a Medication

Abstract

There is a manifest lack of psychometrically sound instruments designed for specific and multidimensional assessment of satisfaction with methadone as a medication within the context of methadone maintenance treatment. Therefore, it may be worthwhile to assess the pertinence and utility of using a generic and multidimensional medication satisfaction instrument that has not been specifically developed for use in methadone maintenance treatment.The aim of this study was thus to explore the psychometric properties of the Spanish version of the Treatment Satisfaction Questionnaire for Medication (TSQM version 1.4 [Health Qual Life Outcomes. 2004;2:12]) in a sample of methadone-maintained heroin-dependent patients.Two hundred three methadone-maintained patients filled out the TSQM and other several measures related to the construct of patient satisfaction (eg, Verona Service Satisfaction Scale for methadone treatment). Dimensionality of the TSQM was assessed by means of a confirmatory factor analysis. Internal consistency was examined using the ordinal coefficient α. Spearman correlations were used to explore the relationship between the TSQM and the measures conceptually related to patient satisfaction.Regarding the dimensionality of the TSQM, its original factor structure adequately fitted the data (Satorra-Bentler χ58, 72.14 [P = 0.100]; root-mean-square error of approximation, 0.045; comparative fit index, 0.978). All but 1 of the 4 TSQM subscales showed acceptable to good internal consistency values (0.78-0.89). The dimensions of the TSQM were differentially and congruently correlated with related measures.The results strongly suggest the TSQM value as a brief, generic, and psychometrically sound instrument to assess satisfaction with methadone as a medication in a multidimensional manner. Notwithstanding, more research is needed not only to assess the generalizability of these findings but also to provide pieces of evidence for other psychometric properties, especially the TSQM predictive validity.