Mental Health Outcomes in Transgender and Nonbinary People

Importance Experiences of marginalization by gender minority people may predispose them to poorer mental health outcomes than their cisgender peers. Understanding mental health conditions in transgender (trans) and nonbinary people is an essential step in addressing potential inequities in outcome for gender minority people. Objective To synthesize reviews of mental health and neurodevelopmental conditions in trans and nonbinary people to describe epidemiology, key themes, and research gaps. Evidence Review Three bibliographic databases (Embase, MEDLINE, and PsycINFO) were systematically searched from inception to August 21, 2023, to identify reviews addressing mental health and neurodevelopmental outcomes in trans and nonbinary people. Articles were screened by 2 reviewers and prespecified data were extracted. Quality of included reviews was appraised against AMSTAR2 criteria. Findings Of 7496 unique records, 41 met inclusion criteria with 24 reviews synthesized after excluding those containing overlapping primary studies. Pooled prevalence estimates from meta-analyses were identified for 5 outcomes: suicidal ideation (50%; 95% CI, 42-57), suicide attempts (29%; 95% CI, 25-34), nonsuicidal self-injury (47%; 95% CI, 40-54), eating disorders (18%; 95% CI, 16-19), and autistic spectrum conditions (11%; 95% CI, 8-16). Meta-analyses comparing trans and cisgender groups reported higher odds of suicidal ideation (odds ratio [OR], 3.48; 95% CI, 2.41-4.91), suicide attempts (OR, 3.45; 95% CI, 2.40-4.64), nonsuicidal self-injury (OR, 3.42; 95% CI, 1.99-5.89), and posttraumatic stress disorder (OR, 2.52; 95% CI, 2.22-2.87). Worse outcomes were reported across all narrative syntheses comparing trans and cisgender or general population groups, except for problem gambling, where the limited evidence base was conflicting. No reviews assessed incidence or mortality, and there was limited disaggregation of nonbinary people or by specific gender subgroups (eg, trans men and trans women). Review quality was generally poor. Reviews highlighted heterogeneity in definitions of gender identity and outcome ascertainment, and unrepresentative sample populations as limitations of primary studies. Conclusions and Relevance A growing body of evidence suggests trans people experience worse mental health outcomes than cisgender people, but there are substantial gaps and methodological weaknesses in existing literature. Research applying an intersectional lens, using longitudinal data and reflecting diversity and the experience of multiple disadvantages in the gender minority population is required to ensure evidence-informed policy and health service development.