Abstract
Treatment-resistant depression is a complex condition often requiring specialist psychiatric care. Many different psychiatric, physical and social factors can lead to a poor response to initial treatment of depression, and a careful assessment is required to determine the most appropriate management option. This can be particularly complex in the older population, who often have multiple physical and social comorbidities. We have used a fictional case to illustrate this, alongside an anonymised vignette of someone with personal experience of this condition. We have also provided an overview of the current evidence for treatment options, as well as a discussion of potential aetiological factors. By the end of this article, readers should understand the ambiguity of this diagnostic term, the aetiological factors that need to be assessed and the rationale for the treatment options available. They should be able to recognise how these ideas apply to the geriatric population.