Japan Reports Rise in Dementia-Related Disappearances

The number of people with dementia reported missing in Japan rose from 9,607 in 2012 to 18,121 in 2024, according to the National Police Agency. Of the 2024 cases, 491 people were later found dead and 273 remained missing at year-end. A follow-up survey showed 171 cases still unresolved at the end of 2025.

Retired chef Hideo Sakamoto, 73, left his Nagasaki home for an evening walk on April 16, 2023, and has not been found. He had been diagnosed with early-stage dementia in 2012 but lived independently and remembered his name and phone number. His wife called him three times that evening; each time he answered only to say he was coming home before hanging up.

m. Officers and police dogs searched the area while family members retraced possible routes. Posters and social media appeals followed. Three years later, the case remains open.

Research by the Tokyo Metropolitan Institute for Geriatrics and Gerontology links longer missing periods to higher death rates, with drowning and hypothermia the most common causes. Adjunct researcher Kazunori Kikuchi said survival chances drop sharply after the third day and that immediate police notification is the most important factor.

Kikuchi noted that people with mild dementia can also disappear because they retain the ability to walk long distances without attracting attention. 9 percent by 2040.

Sakamoto’s daughter, Aiko Eto, later formed a support network for families in similar situations. She said her mother, now 79, continues to seek closure while the uncertainty persists.