Background Delirium superimposed on dementia (DSD) affects the physical, mental and cognitive well-being of the person. The separation of physical health and mental health means that the care of people with DSD is at odds with the multifaceted aetiology and presentation of the condition. There is a lack of research on DSD from a mental health perspective.

Aim To explore UK mental health nurses’ experiences of providing care for people with DSD.

Method Individual semi-structured interviews were conducted with seven mental health nurses from one NHS trust in England. Participants’ experiences were considered through the lens of second-generation activity theory. Data were analysed using framework analysis.

Findings Six themes were identified: awareness of guidance and tools; guidance or tools as ‘paper exercises’; knowing the patient; the multidisciplinary team; care burden; and mental health versus physical health.

Conclusion When providing care for people with DSD, mental health nurses use their skills in knowing patients as individuals. However, this aspect of ‘knowing’ cannot be readily translated into the use of a numerical scoring tool. An integrated approach is required to support the care of people with DSD.