[Challenges, prevention, and countermeasures for social withdrawal (hikikomori) by age group].

　The term "hikikomori" was recognized by society between 1980 and 2000, when the term "NEET" also appeared and it was regarded as a problem of irresponsible youth. However, accumulation of surveys and research both in Japan and abroad, including those conducted by the Cabinet Office, has revealed that the reasons behind social withdrawal are not only limited to mental illness. There are many people who exhibit withdrawal because they are unable to establish relationships with the community and other people owing to various factors such as social systems, attachment formation, family background, and education. In other words, withdrawal is better described as a "symptom" or "condition" than a disease. Therefore, it is necessary to understand and analyze the diverse backgrounds and needs of individuals with withdrawal and confront them about their state. Currently, many hikikomori people with prolonged withdrawal are now in their 40s and 50s. With their parents' aging, there are cases where people with hikikomori and their families become socially isolated and are unable to make ends meet. It is undeniable that, until now, the society we live in as a whole has little interest in or understanding of hikikomori. In contrast, withdrawal among older adults (tojikomori), which has become a problem in the super-aging society. Tojikomori is defined as "going out less than once a week and not requiring nursing care", which is not equivalent with hikikomori. Owing to the decline in the frequency of going out among the elderly in the recent coronary crisis, the number of pre-frailty in older adults has become a nationwide problem.　Thus, both hikikomori and tojikomori are reversible conditions, and can be alleviated by providing necessary support. This paper summarizes the findings of the symposium "Challenges, Prevention, and Countermeasures for Social Withdrawal (Hikikomori) by Age Group" organized by the Committee on Mental Health and Suicide Prevention of the Japanese Society of Public Health at the 79th Annual Meeting of the Japanese Society of Public Health. This article is a compilation of findings that can benefit public health practitioners and researchers.