Adolescents who undergo sex alteration procedures experience a sharp rise in severe psychiatric illness in the years that follow, a landmark Finnish study has found.
The peer-reviewed study, published this week in Acta Paediatrica found that specialist psychiatric treatment rates rose more than sixfold among males and more than doubled in females after intervention.
Led by Professor Riittakerttu Kaltiala of Tampere University Hospital, the study tracked every young person under 23 who contacted Finland's nationally centralised gender identity clinics between 1996 and 2019. The cohort of 2,083 individuals was followed for up to 25 years, compared against 16,643 matched population controls.
Because Finland's health registers are mandatory and patients cannot opt out, the dataset captured the complete fate of every gender-referred adolescent in the country over that period.
"Severe psychiatric morbidity is common among gender-referred adolescents and appears to be more prevalent in those referred after the recent surge in referrals," the study's authors concluded.
"Psychiatric needs do not subside after medical gender reassignment."
The study's core findings on those who underwent procedures are as follows:
Among adolescents who underwent medical gender reassignment, psychiatric morbidity increased markedly during follow-up -- rising from 9.8% to 60.7% in feminising gender reassignment and from 21.6% to 54.5% in masculinising gender reassignment.
Even after adjusting for prior psychiatric history, every subgroup of gender-referred adolescents -- whether or not they had undergone the procedures -- faced substantially elevated ongoing psychiatric risk.
Adjusted hazard ratios placed them at approximately five times higher risk than male population controls and three times higher than female controls.
The authors noted that in some individuals, the medical procedures "appear to be linked to deterioration in mental health."
The study also identified a marked difference between earlier and later referral cohorts.
Those referred after 2010 -- when Finland saw a tenfold rise in referrals -- arrived with significantly greater pre-existing psychiatric needs. Among the later cohort, 47.9 per cent had already required specialist psychiatric treatment before their first clinic contact, against 15.3 per cent among matched controls in the same period. No equivalent rise appeared in the control group.
The authors noted the pattern may indicate that for some adolescents, mental health difficulties are presenting as concerns about gender identity.
The Finnish findings arrive amid a contested policy environment in Australia. Queensland's LNP government has suspended the initiation of puberty-suppressing drugs and cross-sex hormones for minors until at least 2031, pending its own state-level review.
The federal government has separately tasked the National Health and Medical Research Council with updating Australian clinical guidelines, with interim advice on puberty-suppressing drugs expected by mid-2026.
The UK's Cass Review -- a four-year NHS-commissioned independent inquiry -- found the evidence base for puberty-suppressing drugs and cross-sex hormones in minors to be "remarkably weak", prompting the UK to restrict routine prescribing.
The Cass Review rated Australia's child 'gender medicine' standards just 19 out of 100 for rigour of development.
Kaltiala has led Tampere University Hospital's youth gender clinic since 2011 and served on the Cass Review advisory board. She has previously stated that young patients at her clinic were "not thriving" and that "their lives were deteriorating."
Two Australian clinicians who raised concerns about child 'gender medicine' have faced regulatory action.
Queensland psychiatrist Dr Andrew Amos was banned by AHPRA for publicly questioning the contested treatments and barred from direct clinical contact. The conditions were imposed following complaints about his social media posts, though no finding of patient harm or unsafe clinical practice were made against him.
Queensland child psychiatrist Dr Jillian Spencer was suspended from Queensland Children's Hospital in 2023 after objecting to the state's child gender treatment model. She was subsequently issued a termination notice one month before an independent panel was due to deliver its findings -- a decision now subject to legal challenge.
The Finnish study adds to the evidence base those clinicians have drawn on.
The study's authors have called for thorough psychiatric assessment and ongoing treatment before and after any medical procedures.
"The considerable severe psychiatric morbidity prior to contacting the GIS, and its increase over time, suggest that for some of these adolescents, GD may be secondary to other mental health challenges," they wrote. "Psychiatric needs must be adequately met."