When should the driver with a history of substance misuse be allowed to return to the wheel? A review of the substance misuse section of the Australian national guidelines.

Assessing fitness to drive in applicants with a historical or current substance use disorder presents a specific clinical challenge. The Australian guidelines require evidence of remission and absence of cognitive change when considering applications for re-licensing driver or individuals applying to reengage in safety-sensitive work. This paper reviews some of the clinical and biochemical indicators that determine whether a particular person is in 'remission' and meets the criteria for return to driving or other safety-sensitive occupation. It provides an overview of the challenges in establishing an evidence-based approach to determining fitness for safety critical activities. There is no internationally accepted definition of 'remission'. Review of the literature and examination of assessment protocols from other national jurisdictions are available for alcohol and the more important drugs of interest in road safety. Assessing fitness to drive when there is a history of substance misuse and/or substance use disorders is a complex issue that requires assessment of biomarkers, clinical findings and clinical assessment before the person returns to driving. We propose that hair testing provides a reliable and reproducible way to demonstrate remission and provide cost-effective monitoring. Standardised psychological tests could provide a reproducible assessment of the cognitive effects of drug use and suitability to resume driving. We recommend that AustRoads amend the national guidelines to reflect an evidence-based approach to assessing fitness to drive after conviction for offences related to alcohol and drug use.