Temporal Fluctuations of Suicide Mortality and Their Attributed Motives in Governmental Databases of Student Suicides in Japan from 2009 to 2025

National crude suicide mortality rates (CMRs) in Japan trended downward throughout the 2010s, yet the CMR for the youth population moved in the opposite direction, rising from the mid-2010s onwards. To clarify the risk groups and underlying mechanisms of increasing student suicides, the temporal fluctuations of CMRs of students in middle school, high school, special vocational school, and university were analyzed by joinpoint regression analysis, and identification of high CMR groups were detected by a linear mixed-effect model using government suicide databases. CMRs of female students in all school categories increased from the mid-2010s. CMRs of male students in middle and high schools increased, whereas those in university and special vocational school moved from a decreasing to a stable level. Among the average of CMRs from 2022 to 2025, the highest CMR was observed in part-time high school students, which was approximately fivefold higher than the average of all students overall. The major leading suicide motives for all student subgroups were concerned with underachievement and career-path-associated problems within school-related problems. Family-related problems, such as conflict with parents and parental reprimands, were leading suicide motives for middle school students, but these impacts attenuated with age. Instead, the impacts of psychiatric disorders, including depression and other psychiatric disorders, enhanced with age. Student suicides attributed in the government suicide database to these leading suicide motives showed an upward inflexion, moving from a decreasing or stable pattern to a rising one, beginning in the mid-2010s. Taken together, these patterns indicate that mental health concerns among students have re-emerged as a substantial motive behind student suicide from the mid-2010s.