AimAlthough the female suicide rate in Japan is one of the highest among OECD countries, little has been done to assess the psychosocial and psychiatric characteristics of Japanese female suicide completers. This study aimed to examine sex differences in psychosocial and psychiatric characteristics of suicide completers using a psychological autopsy study method, and to identify female suicide factors and intervention points to prevent female suicides. MethodsA semi-structured interview was conducted with close family members of adult suicide completers. The interview included questions regarding sociodemographic factors, suicide characteristics, previous suicidal behaviors and a family history of suicidal behaviors, financial problems, and physical/psychiatric problems. Fisher's exact test and the Student's t-test were used to explore sex differences in these survey items, and individual descriptive information of female suicide cases was also examined. ResultsOf the 92 suicide completers, 28 were female and 64 were male. Females had a significantly higher prevalence of a history of self-harm/suicide attempts (P < 0.001). The prevalence of eating disorders was significantly higher among females than males (P < 0.01). ConclusionThe findings of this study highlight the importance of providing psychological and social support to caregivers of those who repeatedly attempt suicide and express suicidal thoughts, and to suggest the need to improve community care systems to be aware of suicide risk factors among female suicide attempters.