What the studies show

Across clinics in Finland, Australia, Italy and Taiwan, the finding that most consistently replicates is that people presenting with gender dysphoria carry a heavy burden of other psychiatric problems and adverse experiences. In Tampere, 75% of 47 adolescents had previously needed specialist mental health care for reasons other than gender, 26% were autistic, and 64% recalled no childhood gender distress (Kaltiala-Heino et al., 2015). In a Sydney service, 88% of 57 children had other diagnoses, they averaged 5.5 adverse childhood experiences versus 1.7 in community controls, and their attachment patterns were indistinguishable from those of children referred for other mental health problems (Kozlowska et al., 2021). Among 118 Italian adults, 29.6% met criteria for a dissociative disorder and 45.8% reported childhood trauma (Colizzi et al., 2015). Detransitioner case series and single-case reports describe similar histories, with mood disorders in 8 of 9 Finnish detransitioners and sexual abuse in 6 (Kettula et al., 2025).

Two national registry studies suggest co-occurring mental illness accounts for much of the elevated suicide risk. In Finland, gender-referred youth had about four times the suicide rate of peers, but after adjusting for specialist psychiatric care the difference fell below twofold and could be chance; the estimate rests on 7 suicides among 2,083 people (Ruuska et al., 2024). In Taiwan, suicide was about four times higher than in matched controls and 2.6 times higher than in siblings, and adjusting for depression attenuated the association most (Hsu et al., 2025). Both studies note that mental illness may lie on the pathway from gender distress rather than act as an independent cause.

Limits of the evidence

Almost all studies here are cross-sectional or clinic-based snapshots, often without comparison groups, so they cannot establish whether trauma, autism or psychiatric illness precede, contribute to or follow gender dysphoria. Several papers from the same teams share patients and should not be counted as independent evidence. Case reports and small detransitioner series offer clinical detail but rely on retrospective, therapist-interpreted accounts, and several authors hold publicly stated positions on affirming care. The registry findings rest on few deaths and lack treatment data (Taiwan) or reliable treatment comparisons (Finland).