Estimates of the prevalence of depression following TBI vary considerably – ranging from 6% to 77% (Rutherford et al., 1977; Varney et al., 1987). This variability not only seriously limits the clinical utility of these findings, but also raises questions about its source. Differences in how depression is conceptualised (diagnosed disorder vs self-reported symptoms), the diagnostic criteria and/or measures that are used to assess depression and a number of patient characteristics (e.g., injury severity), may explain a significant amount of this variance;however, we do not currently know to what extent these variables impact on estimates of the prevalence of depression following TBI.