TDDS — Terminal Delirium-Related Distress Scale

What this tool is and how to interpret its evidence

The Terminal Delirium-Related Distress Scale (TDDS) was developed to examine distress and perceived care surrounding irreversible terminal delirium. It is completed retrospectively by bereaved relatives of people with cancer who died after admission to hospice or a palliative-care unit. It is not a screen, diagnostic interview or patient severity rating. The 24-item questionnaire is organised into five broad areas concerning support for families and respect for the patient, ability to communicate, distressing psychiatric experiences, information about delirium treatment, and agitation or restlessness. Readers who need the questionnaire or its response options should use the primary publication rather than reconstructing it from this summary.

Uchida and colleagues developed candidate content from qualitative work and literature review, then retained matters that bereaved families considered important. The validation phase included 281 relatives. Repeated factor analysis supported the proposed structure, correlation with the Care Evaluation Scale supported convergent validity, and reported internal consistency for the full scale was 0.84.

TDDS addresses an important but different question from bedside delirium tools: how terminal delirium and its care were experienced. Recall, grief, service context and cultural expectations may influence responses. Evidence came from Japanese specialist palliative-care settings and should not automatically be generalised to other populations. Scores should support research and care-quality reflection, not be interpreted as confirming delirium or judging an individual clinical decision.