Abstract
BACKGROUND: Self-harm (any self-injury or -poisoning regardless of intent) is highly prevalent in transgender and gender diverse (TGD) populations. It is strongly associated with various adverse health and wellbeing outcomes, including suicide. Despite increased risk, TGD individuals' unique self-harm pathways are not well understood. Following PRISMA guidelines we conducted the first systematic review of risk and protective factors for self-harm in TGD people to identify targets for prevention and intervention. METHODS: We searched five electronic databases (PubMed, PsychInfo, Scopus, MEDLINE, and Web of Science) published from database inception to November 2023 for primary and secondary studies of risk and/or protective factors for self-harm thoughts and behaviours in TGD people. Data was extracted and study quality assessed using Newcastle-Ottawa Scales. FINDINGS: Overall, 78 studies published between 2007 and 2023 from 16 countries (N = 322,144) were eligible for inclusion. Narrative analysis identified six key risk factors for self-harm in TGD people (aged 7-98years) were identified. These are younger age, being assigned female at birth, illicit drug and alcohol use, sexual and physical assault, gender minority stressors (especially discrimination and victimisation), and depression or depressive symptomology. Three important protective factors were identified: social support, connectedness, and school safety. Other possible unique TGD protective factors against self-harm included: chosen name use, gender-identity concordant documentation, and protective state policies. Some evidence of publication bias regarding sample size, non-responders, and confounding variables was identified. INTERPRETATION: This systematic review indicates TGD people may experience a unique self-harm pathway. Importantly, the risk and protective factors we identified provide meaningful targets for intervention. TGD youth and those assigned female at birth are at increased risk. Encouraging TGD people to utilise and foster existing support networks, family/parent and peer support groups, and creating safe, supportive school environments may be critical for self-harm and suicide prevention strategies. Efforts to reduce drug and alcohol use and experiences of gender-based victimisation and discrimination are recommended to reduce self-harm in this high-risk group. Addressing depressive symptoms may reduce gender dysphoria and self-harm. The new evidence presented in this systematic review also indicates TGD people may experience unique pathways to self-harm related to the lack of social acceptance of their gender identity. However, robust longitudinal research which examines gender-specific factors is now necessary to establish this pathway.