Supreme Court decision concerning the responsibility of family members to supervise dementia patients

Supreme Court 3rd Petty Bench decision 1 March 2016

By Tatsuya Sasaki


In Japan, as the country’s “aging society” label suggests, statistics as of 15 September 2015 show that 26.7% of the national population is elderly. Further, approximately 15% of the elderly are affected by dementia, and as the causes of Alzheimer’s disease in particular are yet unknown, this number is increasing each year. With this in mind, I would like to introduce a Supreme Court judgment delivered in March 2016 that was the first to address the issue of the responsibility of family members to supervise dementia patients, whose numbers are predicted to increase substantially in the future.

Background of the case

The case involved a man (A) who was suffering from a severe case of Alzheimer’s disease and was inclined to wander away. While his wife (Y1) was taking a brief nap, A walked away from the house and eventually opened a fence gate at the end of a train platform, went onto the railway tracks and was fatally struck by a train. In response, Central Japan Railway Company (JR Central) sued A’s surviving family members, namely Y1 and her eldest son (Y2), for compensation for the damage that arose from the incident, such as the delay to the train services.

Reason for making Y1 and Y2 parties to the case

  1. Generally, train services are temporarily stopped when there is an accident involving a collision with a train, and the railway operator suffers various damage including loss of operating profit during the time that services were stopped. Therefore, it is possible for the railway operator to claim compensation from the person who caused the accident (or if the person dies, the family members who are the person’s heirs) pursuant to Article 709 of the Civil Code.
  2. On this point, the circumstances are slightly different in this case. JR Central did not sue Y1 and Y2 as the successors of A’s liability to pay compensation for damages, but instead claimed that Y1 and Y2 caused the accident by failing to supervise A. The grounds for this claim were that under Article 713 of the Civil Code, people such as A who suffer from severe dementia lack the capacity to assume liability pursuant to Article 709 because they lack the capacity to appreciate their situation; therefore, A did not bear any tort liability. Meanwhile, Article 714 of the Civil Code provides that the person who bears the legal obligation to supervise a person lacking capacity has the obligation to compensate for any damage the person lacking capacity causes to a third party.
  3. Therefore, the case was contested on the issues of [1] did the duty of supervision apply to Y1 and Y2 and [2] if so, could it be said that Y1 and Y2 failed in their duty to supervise A. The case gained worldwide attention as it was the Supreme Court’s first decision regarding point [1].


Lower-court judgments

The trial court ruled that the duty to supervise A applied to both Y1 and Y2 and the accident occurred because they both failed in this duty to supervise A, thereby granting JR Central’s claim. The appeal court found that the duty to supervise did not apply to Y2 and therefore did not recognise the claim against Y2, but found that Y1 did have the duty to supervise and failed in that duty, so recognized the claim against Y1 only.

Main points from the Supreme Court’s judgment

  1. On point [1] regarding whether Y1 and Y2 were subject to the duty to supervise, the Supreme Court differed from the courts below and ruled that neither were subject to the duty.
  2. First, on the point of whether a legal duty to supervise applies, the court ruled that being a spouse or family member cannot be the foundation for determining a duty to supervise in relation to direct interactions with third parties. Also, regarding adult wards, because there is an obligation to consider the circumstances, the court ruled that the direct statutory duty to supervise did not apply.
    On the other hand, even though the statutory duty to supervise did not apply, the court applied Article 714 (1) of the Civil Code by analogy to determine whether they are equivalent to statutorily obliged supervisors who have an equitable obligation to supervise the person who lacks legal capacity, in light of their family relationship and their contact in daily life.
  3. An important point here is what types of people are “equivalent to statutorily obliged supervisors”.On this point, the Supreme Court ruled that, regarding whether a person is equivalent to a statutorily obliged supervisor, “it should be determined from a viewpoint of whether it is acceptable under the objective circumstances to say that it is reasonable to hold the person accountable for the actions of the mentally disabled person, looking from an equitable position at whether that person is currently supervising the mentally disabled person or it is possible and easy for them to supervise“.In the present case, Y1 was 85 years old at the time that A required care, and Y1 herself was certified as requiring level 1 care herself, so it could not be said that she was realistically capable of supervising A in order to prevent A causing damage to third parties. The court therefore ruled that Y1 was not equivalent to a statutorily obliged supervisor.

    Meanwhile, Y2 had not lived with A for more than 20 years prior to the accident and was living in Yokohama and working in Tokyo at the time of the accident. Therefore, like Y1, he could not be said to be in a position capable of supervising A to prevent A causing damage to third parties. The court therefore ruled that Y2 was also not equivalent to a statutorily obliged supervisor.



This Supreme Court decision only decided whether the duty of supervision applied to the wife and son in this case; it did not make any determination on the point of, if the wife was hypothetically found to have a duty to supervise, to what degree would she have to supervise in order to be found to have not failed in the duty. Therefore, this case is not clear as to what extent the family of a dementia patient must supervise in order to not bear responsibility. However, the judgment is meaningful because it determined that a person who has difficulty providing care will not bear responsibility as a person obliged to supervise. I think this decision provides an opportunity to discuss the issue of the burden of caring for dementia patients placed upon families.

Also, as the number of dementia patients increases each year, when I think about what can be done as a lawyer to reduce the burden of families caring for dementia patients, it may be possible for lawyers to support the people providing care by responding to legal issues such as adult wards and the management of assets.

(Translated from the original Japanese)