This issue of Palliative and Supportive Care, Volume 19, no.3, is a special issue which highlights a number of articles focusing on “delirium in the supportive and palliative care setting.” Since the founding of Palliative and Supportive Care as a journal, the focus of the journal has been of the psychiatric, psycho-social, existential, and spiritual aspects of palliative care. Delirium is the most common neuropsychiatric syndrome encountered in the palliative care setting, and is associated with significant morbidity and mortality, so it is quite consistent with the journal's mission to publish a special issue containing five significant articles on delirium. It is a particular delight for Dr. Soenke Boettger and I to be writing this introductory editorial together for a variety of reasons. On a personal note, Dr. Boettger did his Clinical Fellowship in Consultation-Liaison Psychiatry/Psycho-oncology with us at Memorial Sloan Kettering Cancer Center more than 15 years ago. I had the pleasure of not only being Dr. Boettger's Fellowship Training Director, but also his primary supervisor. During this fellowship, Soenke and I embarked on a series of studies on delirium, most of which have been published in Palliative and Supportive Care. As Dr. Boettger established his own Psychosomatic Medicine program in Zurich, he and his team have continued to conduct important research on delirium, and their productivity is reflected in three delirium research articles in this special issue. Their group has contributed three papers that characterize the prevalence of delirium in the palliative care setting, as well as delirium-related morbidity and mortality.

There are two papers in this issue that Dr. Boettger and I wanted to particularly focus on. The first is by Uchida et al. (Reference Uchida, Akechi and Morita2021) who contribute a new instrument for assessing the irreversibility of delirium. Following an evaluation of delirium instruments in cancer patients at the end of life, Uchida et al. (Reference Uchida, Akechi and Morita2021) developed and validated the Terminal Delirium-Related Distress Scale (TDDS) for the assessing the irreversibility of terminal delirium. This instrument includes 24 items and 5 subscales and showed good internal consistency, as well as good construct and convergent validity. Delirium at the end of life extends to virtually all specialties beyond palliative care, and an instrument measuring the irreversibility of terminal delirium could benefit caregivers in the dying process and critical decision-making at the end of life.

Pediatric delirium is perhaps the most under-researched area in the delirium literature, so each study of pediatric delirium is an exceptionally valuable contribution to clinical care. Del Fabbro et al. (Reference Del Fabbro, Lastrape and Dang2021) at Virginia Commonwealth University demonstrated that pediatric delirium was frequently undocumented or miscoded in the palliative care setting. Their work illustrates the clinical necessity for implementing validated, universal screening tools for delirium in pediatric palliative care populations in order to improve delirium identification and clinical outcomes.

It is our hope that these papers on delirium in the palliative and supportive care setting will be clinically useful to our readers and also stimulate further needed research on delirium.