The aim of this study was to determine the reliability and validity of the Japanese version of Incontinence-Associated Dermatitis and its Severity（IADS）using four original scenarios with photographs and 10 photographs of older Japanese persons with incontinence-associated dermatitis（IAD）. After receiving permission from its developers to translate the original English version of IADS, the authors translated it into Japanese and developed a Japanese version. Using four original scenarios, inter-and intra-rater reliability of 20 health-care practitioners was calculated using coefficient of variation data; the inter-rater correlation was 0.724 and intra-rater correlation 0.868. Using 10 photographs of older Japanese persons with IAD, the inter-rater correlation was 0.359 and intra-rater correlation 0.403. Criterion-related validity was determined by comparing IADS scores and concordance rate of 19 testers with those of a wound, ostomy and continence expert for each category. Using four original scenarios, Spearman’s rank-correlation coefficient of IAD severity scores were from 0.400 to 1.000 and concordance rate for each category as follows: none, 80.0％; red, 55.5％; rash, 36.9％; and skin loss, 51.7％. Using 10 photographs of older Japanese persons with IAD, Spearman’s rank-correlation coefficient of IAD severity scores was from - 0.016 to 0.66 and concordance rate for each category as follows: none, 60.0％; pink, 56.8％; red, 33.1％; rash, 45.5％; and skin loss, 40.3％. These results suggest that the Japanese version of the IADS has satisfactory reliability and validity for persons with light skin color and IAD; however, it is not accurate for yellow skin color or areas of pigmented skin.

　Introduction: It is important to understand the characteristics of pressure ulcers in patients with mental illness to provide appropriate care. This study aimed to determine the relationship between morphological characteristics of pressure ulcers and situations when they occur.
　Methods: We conducted a retrospective study using quantitative and qualitative methods. The quantitative data was collected during pressure ulcer rounds from patients with mental illness and, for comparison, from patients without mental illness. Next, we conducted a qualitative descriptive analysis to examine the morphological characteristics of pressure ulcers in patients with mental illness and the situations in which pressure ulcers occurred.
　Results: Data from 15 patients with mental illness and 262 patients with other diseases were analyzed. Compared to other patients, patients with mental illness were younger, had multiple pressure ulcers, classified as more ambulant, and had higher Braden Scale scores for friction/shear. The number of cases occurring outside the hospital was significantly higher. The morphological characteristics of pressure ulcers in patients with mental illness and the situations in which pressure ulcers occurred were defined as follows: shapes（cloud shape and sharp shape）; color（single-color and multi-color）; external force on the ulcer region（wiggle, flounder, stillness, and self-injurious behavior）; and occurrence factors（excessive administration of psychiatric medicine, drug overdose, physical restraint, and circulatory failure）.
　Conclusion: Many patients with mental illness had 2 or more pressure ulcers, more ambulant, and are younger. The factors associated with occurrence of pressure ulcers were an external force caused by body movement and self-injurious behavior, and care included psychiatric medicine dosage and physical restraint.