Responding to Sundowning and Difficult Dementia Behaviors in Japan

Difficult behavior is communication, not the disease being difficult

When a parent with dementia becomes agitated, accusatory, or aggressive, it is easy to experience it as the disease turning them into someone else. A more useful frame, and the one professionals work from, is that the behavior is communication: an unmet need or a distress the person can no longer put into words.

This article is general orientation, not medical advice. Japan's official guidance on these symptoms (known as the behavioral and psychological symptoms of dementia) is that the first-line response is non-drug: look at the physical and environmental triggers before anything else, and turn to medication only when those measures are not enough (the position of Japan's multi-society BPSD guideline for primary-care and dementia-support doctors, 2025 edition). That is good news for families, because it means much of what helps is within reach at home, through understanding and adjustment rather than only medication, which is a doctor's decision and not something to pursue from a distance.

First, rule out a physical cause with the doctor

A sudden change in behavior, or a sharp new agitation, is not always the dementia progressing. In an older person it can be the visible sign of a physical problem they cannot describe, and that possibility comes first.

Pain, an infection, constipation, dehydration, hunger or thirst, poor sleep, a new medication, or a too-hot or too-cold room can all drive agitation in someone who can no longer say what is wrong. A noticeable change, especially a sudden one, is a reason to involve the parent's doctor rather than to assume it is simply a worse day, since treating the hidden cause often settles the behavior. This is not something to diagnose from afar; it is a prompt to get a professional looking, and our article on caring for a sick parent covers how a sudden change can be medical.

Sundowning: why evenings are hard

Many families notice that confusion and agitation peak in the late afternoon and evening, a pattern often called sundowning. The exact causes are not fully understood, but the practical levers that reduce it are well established and entirely non-medical.

• Let in daylight during the day and keep the evening well lit, since dim light and shadows feed confusion and fear
• Keep a steady daily rhythm with familiar anchors, since predictability is calming and disruption is not
• Move demanding activities, appointments, and bathing to earlier in the day when the person has more reserve
• Wind the evening down: less noise, fewer people, no overstimulating television, a calm and quiet routine toward sleep
• Watch caffeine, late naps, hunger, and tiredness, since each can sharpen the evening, and a day-service program can provide the daytime activity that improves the night

De-escalating agitation in the moment

When a parent is already agitated or angry, the instinct to correct, reason, or restrain usually makes it worse. A different set of responses calms most situations, and they can be learned.

• Do not argue with the content or correct the facts: if a parent insists money was stolen or a dead relative is visiting, arguing escalates, while acknowledging the feeling defuses
• Validate the emotion, not the delusion: "that sounds frightening, I am here" reaches a person that "you're wrong" cannot
• Reduce the trigger: lower noise, dim a harsh light, clear a crowded room, and give the person physical space rather than crowding them
• Redirect gently toward something familiar and soothing, a walk, a task, music, food, rather than insisting on the thing that sparked the upset
• Keep everyone safe first: if there is a risk of harm, step back and give room rather than restraining, and treat repeated or dangerous aggression as a reason to get professional help, not to cope alone
• Afterward, look for the pattern: note when the upset happened, what came just before it, and what helped, since these episodes usually have triggers, and a written record turns a frightening moment into information the doctor and care manager can act on

What sits beyond the family, and Japan's professional support

Behavior management is partly a home skill and partly a job for professionals, and knowing the line keeps families from carrying too much alone.

Some behavior needs specialist input. Japan's dementia medical centers (ninchishou shikkan iryou center) assess and support these symptoms alongside the medical side, the parent's doctor and a care manager can adjust the care plan and day-service mix that so often improves behavior, and dementia cafes give caregivers a place to learn and breathe. Whether medication ever has a role is strictly a doctor's decision, made cautiously, with the official position being that non-drug approaches come first. For the wider dementia picture, including diagnosis, the support networks, and what to do if a parent wanders or goes missing, see our guide to dementia care in Japan; this article is the day-to-day behavior companion to it.

Dementia is common in Japan, so the support around it is developed. An official 2024 estimate put about 4.43 million people aged 65 and over living with dementia in 2022, roughly one in eight of that age group (Cabinet Secretariat), and the public structures built around that number are ones a family abroad can name and point a parent toward. The single most useful thing to know is that almost all of it can be reached through one door: the local community support center.

Doing this from a distance, and protecting the carer

Difficult behavior is exhausting for whoever is in the room, and for a family abroad it is hard to gauge and harder to support. Both problems have practical answers.

From a distance, make sure a real change in behavior reaches the doctor and care manager rather than just wearing down the local caregiver, and build the day-service and respite support that lightens the hardest hours. For whoever is hands-on, this is some of the most draining care there is, and the resentment and exhaustion it produces are normal, not a failure, which our article on caregiver burnout addresses directly. Protecting that person, with breaks, shared load, and professional support, is part of caring for the parent. This remains general guidance: the medical questions, and any change in symptoms, belong with the parent's doctor and the dementia specialists who can see the whole picture.