Effect of ninjin'yoeito, a Kampo (traditional Japanese) medicine, on cognitive impairment and depression in patients with Alzheimer's disease: 2 years of observation

Abstract Background Only a few approved drugs are capable of alleviating the cognitive and behavioural symptoms of people living with A lzheimer's disease ( AD ). In recent years, however, the number of studies examining the clinical effects of herbal medicines on cognitive function in patients with AD has increased considerably. This study evaluated the long‐term effects of a traditional Japanese medicine ( K ampo medicine) known as ninjin'yoeito ( NYT ) on cognitive impairment and mood status in patients with AD over a 2‐year period. Methods Twenty‐three patients with mild‐to‐moderate probable AD according to the N ational I nstitute of N eurological and C ommunicative D isorders and S troke and A lzheimer's D isease and R elated D isorders A ssociation criteria were included. Each participant had exhibited an insufficient response to treatment with donepezil alone before the start of the trial. Eleven patients received treatment with donepezil alone, and the remaining patients received a combined treatment of donepezil and NYT for 2 years. Patients were assessed by the M ini‐ M ental S tate E xamination and the A lzheimer's D isease A ssessment S cale‐cognitive component‐ J apanese version for cognitive function, and the N europsychiatric I nventory was used to evaluate the patients' mood status at baseline and every 6 months for 2 years. Results The M ini‐ M ental S tate E xamination results showed no significant differences between the two groups. Significant improvements were observed on the A lzheimer's D isease A ssessment S cale‐cognitive component‐ J apanese version and the N europsychiatric I nventory depression scores of patients who received the combined therapy with donepezil and NYT ( A lzheimer's D isease A ssessment S cale‐cognitive component‐ J apanese version, 12 months: P < 0.01, 18 months: P = 0.04, 24 months: P < 0.01; N europsychiatric I nventory depression, 6 months: P < 0.05, 24 months: P < 0.05). Conclusions A 2‐year follow‐up of patients receiving donepezil and NYT treatment showed an improved cognitive outcome and alleviation of AD ‐related depression.