Prevalence and associated factors of suicidality in Japanese adolescents: results from a population-based questionnaire survey.

BACKGROUND: Suicide is the leading cause of death among Japanese adolescents. However, knowledge gaps regarding contemporary demographics and factors associated with suicidality among Japanese adolescents are a major concern. This study examined the prevalence of suicidality among Japanese adolescents and investigated associated factors. METHODS: A population-based questionnaire survey investigating general health was administered to 22,419 adolescents aged 13-18 years. The 29-item questionnaire covered emotional status, family function, cyberbullying, suicidality, and stressors (e.g., relationships with parents/friends, school performance, and sexual identity). We conducted multiple logistic regression analysis to identify factors associated with suicidality in this population. RESULTS: The prevalence of suicidal ideation was 21.6% in males and 28.5% in females, and that of attempted suicide was 3.5% in males and 6.6% and in females. Bullying and stress related to family relationships had the strongest associations with suicidality. Exposure to cyberbullying had the highest odds ratio for both junior high (3.1, 95% confidence interval [CI] 2.1-4.4) and high school students (3.6, 95% CI 2.5-5.3). Other factors significantly associated with suicidality were sex, emotional status, and stress about relationships with friends, sexual identity, school records, and academic course. Adolescents accessed a variety of resources to cope with stressors, with the Internet being the most common resource consulted. CONCLUSIONS: Suicidality is commonly experienced among Japanese adolescents. Although there are many associated risk factors, cyberbullying is of particular concern. Recognition of factors associated with adolescent suicidality will inform further research and suicide prevention efforts for healthcare providers and families.

Chronotropic incompetence to exercise in anorexia nervosa patients during the body-weight recovery phase as an index of insufficient treatment.

Resting bradycardia is an important symptom for early diagnosis of anorexia nervosa (AN) during weight loss, and it improves with body-weight recovery. However, chronotropic incompetence (CI) in exercise is observed in some patients with AN despite amelioration of resting bradycardia in the recovery phase. We examined the relationship between CI in exercise and other parameters in patients with AN during the recovery phase. Ninety-two girls with AN (aged 13-20 years, median 15 years) performed cardiopulmonary exercise tolerance tests with a bicycle ergometer in the post-treatment recovery phase. Subjects with a peak-heart rate (HR) of < 160 beats/min (bpm) on subjective maximum loading were assigned to the CI+ group (n = 7), and those with a peak-HR of ≥ 160 bpm were assigned to the CI- group (n = 85). The peak-oxygen uptake (VO2) of both groups was below the normal range. Although there was no difference in peak-VO2 between these groups, both the resting-HR and ΔHR (peak-HR - resting-HR) were significantly lower in the CI+ group than in the CI- group (82 ± 8 vs. 93 ± 16 bpm, respectively; 72 ± 14 vs. 89 ± 13 bpm, respectively), suggesting lower exercise tolerance in patients with CI during the recovery phase of AN. Interestingly, the ΔVO2/ΔHR value was higher in the CI+ group than in the CI- group (0.31 ± 0.13 vs. 0.26 ± 0.06, respectively), suggesting excessive stroke volume for maintaining the cardiac output in patients with CI during their recovery phase. These data suggest that CI could be an index of insufficient recovery of AN and utilized for ideal exercise treatments of patients with AN during the recovery phase.