Improvement in delusions and hallucinations in patients with dementia with Lewy bodies upon administration of yokukansan, a traditional Japanese medicine


Dr Kenji Kosaka MD PhD, Medical Care Court Clinic, 3-23-25 Edanishi, Aoba-ku, Yokohama, Kanagawa 225-0014, Japan. Email:


Background:  This multicentre open-label trial examined the efficacy and safety of the traditional Japanese medicine, or Kampo medicine, yokukansan (YKS), for behavioural and psychological symptoms of dementia (BPSD) in patients with dementia with Lewy bodies.

Methods:  Sixty-three dementia with Lewy bodies patients with probable BPSD (M : W, 30 : 33; mean age, 78.2 ± 5.8 years) were enrolled and treated with YKS for 4 weeks.

Results:  Significant improvements in Neuropsychiatric Inventory scores (mean decrease, 12.5 points; P < 0.001) and Zarit Burden Interview-Japanese edition tests (mean decrease, 3.6 points; P= 0.024) were observed. In patients who consented to an assessment after 2 weeks of treatment, a time-dependent significant improvement was observed in the Neuropsychiatric Inventory score (n= 23; mean decrease, 14.4; P < 0.001), each subscale, including delusions and hallucinations, the Zarit Burden Interview-Japanese edition (n= 22; mean decrease, 8.2; P < 0.01) and the behavioural pathology in Alzheimer's disease insomnia subscale. The Mini-Mental State Examination and the Disability Assessment for Dementia (DAD) showed no significant change. Adverse events were observed in 11 (18%) patients. Three patients (5%) discontinued YKS due to adverse reactions, namely, spasticity and exacerbation of BPSD, edema, and nausea. Hypokalaemia (<3.5 mEq/L) was present in four patients (6%) at the study endpoint. Worsening of extrapyramidal symptoms was not observed.

Conclusion:  YKS improved BPSD in dementia with Lewy bodies patients and caregiver burden scores without deterioration in cognitive function. YKS is useful for the treatment of delusions and hallucinations in BPSD.