A multifaceted understanding of the drug phenomenon through a multi-method research design: a scoping review

Monitoring the drug phenomenon is inherently complex and requires well-designed research methods that adequately capture its multidisciplinary nature, including supply-and-demand-related aspects. Single-method approaches provide only a partial understanding due to inherent limitations of individual methods, emphasizing the need for alternative methodologies to provide comprehensive, reliable, and timely insights. This scoping review examines the application of multi-method approaches in monitoring the drug phenomenon, specifically focusing on the identification of studies combining three or more data collection methods. The review protocol was defined a priori in accordance with Joanna Briggs Institute guidance. PubMed, Scopus and Web of Science were searched in October 2024, as well as grey literature in December 2024, and English-language articles published from 1 January 2000 onwards were screened for inclusion. Analysis of 78 eligible articles illustrated three key strengths of multi-method approaches: (i) the examination of multiple facets of the drug phenomenon; (ii) the inclusion of multiple diverse perspectives and participant profiles; and (iii) the integration of findings across data sources through cross-validation, identification of (in)consistencies, and mutual enrichment. Multi-method approaches provide more contextualized and robust monitoring insights than single-method designs by addressing the limitations of individual data sources and enabling a comprehensive and multifaceted understanding. Multi-method research designs represent a valuable methodological option to achieve a comprehensive understanding of the complex and evolving drug phenomenon, through three key strengths. Once a clear research question has been defined, it should be considered to use a multi-method design, supported by careful methodological integration.