Increasing Suicide Mortality of Female Students Became Greater than Males in Current Japan

In Japan, national crude suicide mortality rates (CMR-suicides) consistently decreased during the 2010s, whereas adolescent CMR-suicides have increased from the mid-2010s. However, the high-risk groups and their causalities remain to be clarified. Temporal fluctuations of adolescent CMR-suicides disaggregated by gender, age, social standing, and suicide motive were analyzed with joinpoint regression and linear mixed-effect models using two government suicide databases. CMR-suicides among female elementary school students, middle school students, high school students, university students, and <20-year-old individuals with social withdrawal syndrome (SWS) increased from the mid-2010s. CMR-suicides among male elementary school, middle school, and high school students also increased from the mid-2010s, while those of university students were unchanged. In contrast, CMR-suicides of males aged <20 and 20–29 with SWS unexpectedly decreased. Surprisingly, the increasing trends of CMR-suicides of female students were greater than males; consequently, CMR-suicides of female students in middle school and high school became greater than those of male students in the 2020s. The highest suicide risk among those under 20 years of age was observed among part-time high school students. Among individuals 20–29 years of age, those with SWS were in the highest-risk group for suicide, while CMR-suicides of individuals with SWS aged under 20 years were almost equivalent to those of middle school students. The leading suicide motives for elementary school students were family-related, including family discord and parental reprimand (there was no difference in gender in terms of leading suicide motive). Among middle school female students and older, the leading suicide motives were mental issues followed by school-related problems. Among male middle school students and older, the leading suicide motives were underachievement followed by mental issues. CMR-suicides caused by mental issues (for both genders) and underachievement (in males) increased from the mid-2010s. These results suggest that increasing internalizing problems may be a fundamental factor contributing to the currently increasing suicides among adolescents (particularly females) in Japan. Although the recent promotion of inclusive education in Japan has successfully provided educational opportunities for individuals with internalizing problems, these statistics highlight the need for a further enhancement of psychosocial support for adolescents with internalizing problems who are at a high risk for suicide.