Effect of a companion dog on depression and anxiety levels of elderly residents in a long-term care facility

The aim of the present study was to evaluate the relationship between aging and the behavioral and psychological symptoms of dementia (BPSD) in patients with Alzheimer's disease (AD). Eligible subjects were consecutively referred AD patients with BPSD. According to patient age at the time of the test, the AD patient group (n = 79, whole AD group (WADG)) was divided into two groups: a relative older group (OG) in the whole AD group (WAD) (age at the time of test was 81 years or more, n = 40) and a relative younger group (YG) in the WAD (age at the time of test was below 81 years, n = 39). A comparison was made of the demographic data (sex difference, educational level and severity of dementia), cognitive functions and BPSD between the groups. BPSD was evaluated using the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD). The factor analysis of BPSD was conducted in the WADG as well as in the OG and YG. Sex difference, educational level, severity of dementia and cognitive functions were not different; however, the total score of the BEHAVE-AD symptom domain in diurnal rhythm was significantly higher in the OG than in the YG (Student's t-test: P < 0.05). Factor analysis showed that psychosis was the first factor in the OG, but was the third factor in the YG and that the psychotic symptoms were caused by anxieties and phobias in the OG. From these results, we found that the effects of aging on the BPSD in AD were characterized by diurnal rhythm disturbance and psychosis.