Substance Use Sex Index (SUSI): towards a new behaviour change assessment tool

Background: Existing tools for measuring behaviours that may risk human immunodeficiency virus, other blood-borne virus and sexually transmitted infection (HIV/BBV/STI) in drug and alcohol research have not evolved alongside treatment and prevention innovations, or accounted for sexualised substance use in a range of social, cultural and epidemiological contexts.

Developed and piloted in 2016, the Substance Use Sex Index (SUSI) is a 23-item questionnaire designed to measure sexualised substance use among diverse populations. Initial research evaluated predictive, content and concurrent validity with encouraging results that support SUSI’s conceptual basis..

Methods: The scale has been refined and will be validated for reliability and validity with an online sample of Australian residents aged 18 years or over (n = 400).

Results: The tool will be presented alongside findings on scale structure, item scaling, test-retest reliability and criterion validity against the Opiate Treatment Index HIV Risk-Taking Behaviour Scale (OTI-HRBS), widely used in drug treatment studies.

Conclusions: The tool is built on promising results obtained from the pilot evaluation to further develop SUSI as a psychometrically robust questionnaire. SUSI has the potential to provide a new tool for measuring change in HIV/BBV/STI transmission risk behaviours within drug and alcohol treatment research, with greater inclusiveness of experience across a range of populations. Widespread use of SUSI will inform the development of effective risk reduction strategies that take relevant substance use and sexual practices into account.