Clinical characteristics associated with non-suicidal self-injury among Japanese adolescents-Relationship between non-suicidal self-injury and psychosomatic symptoms: a retrospective cross-sectional study

AI Summary

NSSI occurred in 12.2% of adolescent psychiatric outpatients (59/417).
NSSI was associated with fewer clinician-assessed psychosomatic symptoms, indicating the need to screen despite minimal physical complaints.
Female sex, bullying history, depressive symptoms, suicidal thoughts, and absence of family psychiatric history were significantly associated with NSSI.

BMC Psychiatry. 2026 May 19. doi: 10.1186/s12888-026-08100-2. Online ahead of print.

ABSTRACT

BACKGROUND: Non-suicidal self-injury (NSSI) is an intentional but non-lethal form of bodily harm inflicted upon oneself. Difficulties in identifying and expressing emotions may underlie psychosomatic symptoms and self-harm. However, the relationship between NSSI and psychosomatic symptoms remains unclear. This study examined demographic and clinical factors associated with NSSI among Japanese adolescents.

METHODS: This retrospective cross-sectional study included 485 adolescent outpatients in a Japanese psychiatric setting between July 2019 and May 2021 (mean age 14.64 ± 1.65 years; 248 boys and 237 girls). NSSI and related clinical features were assessed using diagnostic interviews and self-report questionnaires. Psychosomatic symptoms were categorized according to clinician judgment, reflecting routine clinical practice. Patients with insufficient information, intellectual disabilities, or a history of suicide attempts or indirect self-harm (e.g., substance abuse, eating disorders, or risk-taking behaviors) were excluded. Multiple logistic regression analyses were conducted to identify associative, rather than causal, factors related to NSSI.

RESULTS: Of the 417 adolescents included in the analysis, 59 (12.2%) engaged in NSSI. Logistic regression identified six factors significantly associated with NSSI: female sex(OR = 3.05, 95% CI: 1.51-6.16, p =.002), fewer psychosomatic symptoms (OR = 0.44, 95% CI: 0.24-0.82, p =.01), a history of being bullied (OR = 2.14, 95% CI: 1.03-4.41, p =.04), no family history of psychiatric disorders (OR = 0.40, 95% CI: 0.18-0.86, p =.02), depressive symptoms (OR = 1.08, 95% CI: 1.02-1.15, p =.013), and suicidal thoughts (OR = 2.13, 95% CI: 1.05-4.32, p =.037). No multicollinearity concerns were observed (all VIF < 1.5).

CONCLUSIONS: Adolescents who engaged in NSSI exhibited fewer clinician-assessed psychosomatic symptoms than those who did not engage in NSSI. Several factors, including female sex, fewer psychosomatic symptoms, bullying experiences, family history of psychiatric disorders, depressive symptoms, and suicidal thoughts, were associated with NSSI. These findings underscore the importance of screening for NSSI, even among adolescents who present with minimal physical complaints.

CLINICAL TRIAL NUMBER: Not applicable.

PMID:42157189 | DOI:10.1186/s12888-026-08100-2

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