On the likelihood of mental health deterioration on hormonal treatments

New research findings, error in the evidence brief, and the Ministry’s position statement commitments

Apr 15, 2026

The following email was sent to the Ministry of Health on the 14th of April 2026.

To: Dr Joe Bourne and Steve Barnes

cc: Dame Helen Stokes-Lampard, Health and Disability Commission, Simeon Brown, Matt Doocey, Casey Costello

Tēnā koutou,

I am writing regarding the Ministry’s November 2024 position statement on Use of Puberty Blockers in Gender-Affirming Care, in which the Ministry committed to:

“continue to monitor emerging evidence”,
“enhance governance and monitoring of gender-affirming care to ensure the safe and evidence-based delivery of gender-affirming care.”, and
Noted the establishment of an “external advisory group to consider system wide issues and provide advice relating to gender-affirming care.”

A recently published study, alongside other recent evidence, overseas developments and a material error in the Ministry’s evidence brief bear directly on these commitments. I draw them to the Ministry’s attention because of the Ministry’s overarching responsibility to oversee safe prescribing and to provide accurate information to health consumers and their whanau’s rights regarding treatment options.

The study and other research

Ruuska et al. (2026) have published a nationally representative register study in Acta Paediatrica covering all 2,083 individuals under 23 who contacted Finland’s specialised gender identity services between 1996 and 2019.

Among males receiving estrogen and related treatment, the proportion requiring specialist-level psychiatric care rose from 9.8% before referral to 60.7% in follow-up. Among females receiving testosterone and related treatments, the increase was from 21.6% to 54.5%. In the control population, by contrast, the rate remained essentially unchanged.

The authors state that their findings do “not support the suggested improvement in mental health after medical [intervention] initiated during developmental years, “ and that it “should be noted that in some individuals, medical [intervention] appears to be linked to deterioration in mental health.”

While causality cannot be determined, recent findings from other jurisdictions point in the same direction: McPherson & Freedman (2024) found 15–34% of UK adolescents on puberty blockers deteriorated; Wong et al. (2026) found social support, not medical treatment, predicted mood improvement in Hong Kong; Straub et al. (2024) found a 4.71-fold elevated suicide risk after sex trait modification surgery compared to propensity matched controls in the US; Saxby et al. (2026) found sustained increases in antidepressant prescriptions among Australian cross-sex hormone recipients; while Chen et al. (2023) (which is sometimes used to support the proposition of mental health benefit) reported that two young participants out of a total of 315 committed suicide while being treated with cross-sex hormones.

The nature and purpose of the treatment

The early intervention model involves reinforcing the child’s belief that they are the opposite sex and prescribing hormonal treatments that suppress normal sex hormones and/or introduce supraphysiological levels of cross-sex hormones. Surgeries can also alter hormone production permanently. Sex hormones regulate mood, and GnRH agonists carry adverse effect warnings for mood swings and depression. The possibility that suppressing or disrupting the hormonal milieu of developing adolescents could worsen their mental health is a foreseeable outcome.

Despite this foreseeability the Ministry has recommended off-label hormonal interventions as first-line treatments to minors since 2011 (Ministry of Health, 2011). The recommendation was partially based on the proposition that these interventions would “[alleviate] some of the psychological distress associated with gender variance” (p. 22), although prominent advocates have now apparently abandoned* the mental health improvement proposition in regards to puberty blockers.

With an awareness of these issues, the new NHS gender clinics have not prescribed cross-sex hormones to any minor despite this being lawful (Spencer, 2025; UK Parliament, 2025). The NHS is now consulting on whether to formalise this clinical judgment by banning cross-sex hormones for minors alongside the existing ban on puberty blockers (NHS England, 2026).

These developments, as well as a material error in the evidence brief’s interpretation of Staphorsius et al. (2015) (see Appendix 1), require the Ministry to address the following:

(1) Should the Ministry consider the possibilities that the treatments have no mental health benefit, or make mental health worse for a majority or subset of patients; and raise these possibilities in advice to the Minister?

(2) How likely does the Ministry consider these possibilities to be? What evidence does the Ministry rely on to support the assumption that the treatments improve mental health?

(3) If the Ministry accepts that these possibilities are non-trivial, and noting that it is prior to the consideration of other, not insubstantial, risks, what are the Ministry’s responsibilities regarding the regulation of such interventions?

(4) Health NZ continues to promote the early intervention model. Under the Code of Health and Disability Services Consumers’ Rights 1996, providers are obligated to deliver services of an appropriate standard (Right 4) and to ensure informed consent (Right 6). The obligations under the Code fall on providers, but the Ministry publishes the evidence briefs on which clinicians rely when obtaining informed consent under Right 6. The Ministry therefore contributes to the conditions under which valid informed consent cannot be obtained. The Ministry also has stewardship responsibilities under the Pae Ora (Healthy Futures) Act 2022. At what point does the accumulating evidence outlined above mean that continuing to allow the prescribing of these treatments, without correcting a known error in the evidence brief and communicating new findings to clinicians and families, constitutes a failure of that stewardship? I ask the Ministry to obtain and share legal advice on this question. I note that this letter, and the evidence it contains, is now in the Ministry’s and the HDC’s possession.

OIA requests and erratum

(1) Evidence brief correction. I request the Ministry correct the misinterpretation of Staphorsius et al. (2015) in the evidence brief and issue an erratum or addendum.

(2) Evidence monitoring commitment. The position statement commits the Ministry to “continue to monitor emerging evidence.” I request under the OIA:

All communications regarding the Ministry’s formal efforts to monitor emerging evidence.
A description of the process the Ministry uses to monitor and assess new publications in this field.
All communications regarding the articles mentioned (Appendix 2). In particular, communications where the Ministry has brought these articles to the attention of the external advisory group.

(3) Advisory group. The position statement refers to an “external advisory group” established to “consider system wide issues and provide advice relating to gender-affirming care.” I request under the OIA the terms of reference for this group, its membership, and any minutes or advice produced to date.

(4) Governance and monitoring of clinical practice. I request under the OIA a description of the steps the Ministry has taken to “enhance governance and monitoring of gender-affirming care to ensure the safe and evidence-based delivery of gender-affirming care.”

I appreciate the Ministry’s attention to these matters and look forward to your response.

Nāku noa, nā

Simon Tegg
Director, Genspect New Zealand

*Abandonment or prior claim of mental health benefit – PATHA exec member Dr Rona Carroll, has stated that puberty blockers “don’t necessarily result in a measurable effect at the time they are taken” and that “the main impact is seen when people are older” (Carroll, 2024). Former PATHA President Dr Veale goes as far to say that “[p]uberty blockers are not a mental health treatment” (Veale, 2025). These statements contradict the referenced earlier claim made in the 2011 guidelines (co-authored by PATHA exec member Dr Rachel Johnson) and the statement in the 2018 guidelines (co-authored by Dr. Veale) that “[t]here is good evidence that puberty blocking…significantly improves mental health and wellbeing outcomes” (Oliphant et al., 2018, p. 17)

Appendix 1 - Error in Evidence Brief

The Ministry’s November 2024 evidence brief on puberty blockers briefly addresses cognitive impacts. The Ministry reviewed a single study, Staphorsius et al. (2015), and described the results in these terms:

“The authors found no significant effect of [blockers] on Tower of London performance scores in either [male] or female] adolescents compared to untreated gender-dysphoric controls. They concluded that there were no detrimental effects of [blockers] on executive function” (p. 14).

However, earlier that year in January 2024 the journal Acta Paediatrica had published a review article on the impacts of puberty blockers on neuropsychological function by Professor of Neuropsychology Sallie Baxendale (2024). This article also examined Staphorsius et al. (2015) but described its results differently:

“While the groups did not differ with respect to reaction time on the Tower of London Test, suppressed male to females had significantly lower accuracy scores compared to the control groups. This pattern remained significant after controlling for IQ. Despite this, the reaction time finding has subsequently been reported as evidence for no detrimental effects on performance in citations in the subsequent literature and in policy documents.” (p. 1163)

It seems that the Ministry has misinterpreted Staphorsius et al. (2015) in the way Professor Baxendale describes.

In addition, the Taylor et al. (2024) systematic review, published as part of the Cass Review earlier that year, included a study, Strang et al. (2021), that the Ministry did not. The inclusion or exclusion of individual studies in systematic reviews is not unusual. However, Strang et al. found that longer duration puberty suppression (>1 year) was associated with worse executive function. The Ministry’s evidence brief did not address this finding.

The error regarding Staphorsius et al.(2015) and the absence of Strang et al. (2021) create a misleading picture of the evidence on cognitive effects. Given that the evidence brief informs both the position statement and clinical practice, this should be corrected.

Appendix 2 - Relevant Studies for the Ministry’s monitoring commitment

McPherson, S., & Freedman, D. E. P. (2024). Psychological Outcomes of 12-15-Year-Olds with Gender Dysphoria Receiving Pubertal Suppression in the UK: Assessing Reliable and Clinically Significant Change. Journal of Sex & Marital Therapy, 50(3), 315–325. https://doi.org/10.1080/0092623X.2023.2281986

Ruuska, S.-M., Tuisku, K., Holttinen, T., & Kaltiala, R. (2026). Psychiatric Morbidity Among Adolescents and Young Adults Who Contacted Specialised Gender Identity Services in Finland in 1996–2019: A Register Study. Acta Paediatrica, n/a(n/a). https://doi.org/10.1111/apa.70533

Saxby, K., Buchmueller, T., Carpenter, C. S., Coman, C., & Nolan, B. J. (2026). Mental health treatment among transgender and gender diverse people following gender affirming hormone therapy: Evidence from whole-of-population Australian administrative data. eClinicalMedicine, 92. https://doi.org/10.1016/j.eclinm.2026.103765

Strang, J. F., Chen, D., Nelson, E., Leibowitz, S. F., Nahata, L., Anthony, L. G., Song, A., Grannis, C., Graham, E., Henise, S., Vilain, E., Sadikova, E., Freeman, A., Pugliese, C., Khawaja, A., Maisashvili, T., Mancilla, M., & Kenworthy, L. (2021). Transgender Youth Executive Functioning: Relationships with Anxiety Symptoms, Autism Spectrum Disorder, and Gender-Affirming Medical Treatment Status. Child Psychiatry & Human Development. https://doi.org/10.1007/s10578-021-01195-6

Straub, J. J., Paul, K. K., Bothwell, L. G., Deshazo, S. J., Golovko, G., Miller, M. S., Jehle, D. V., Straub, J. J., Paul, K. K., Bothwell, L. G., Deshazo, S., Golovko, G., Miller, M., & Jehle, D. V. (2024). Risk of Suicide and Self-Harm Following Gender-Affirmation Surgery. Cureus, 16(4). https://doi.org/10.7759/cureus.57472

Wong, C. Y., Ngan, S. T. J., Cheng, P. W. C., Tang, W. K., Chow, L. Y., & Kam, W. K. (2026). Effect of gender-affirming treatments on depression and anxiety symptoms in transgender people: A retrospective cohort study. Frontiers in Psychiatry, 16. https://doi.org/10.3389/fpsyt.2025.1709778

References

Baxendale, S. (2024). The impact of suppressing puberty on neuropsychological function: A review. Acta Paediatrica, 113(6), 1156–1167. https://doi.org/10.1111/apa.17150

Carroll, R. (2024, December 4). NZ is consulting the public on regulations for puberty blockers – this should be a medical decision not a political one. The Conversation. http://theconversation.com/nz-is-consulting-the-public-on-regulations-for-puberty-blockers-this-should-be-a-medical-decision-not-a-political-one-245020

Chen, D., Berona, J., Chan, Y.-M., Ehrensaft, D., Garofalo, R., Hidalgo, M. A., Rosenthal, S. M., Tishelman, A. C., & Olson-Kennedy, J. (2023). Psychosocial Functioning in Transgender Youth after 2 Years of Hormones. New England Journal of Medicine, 388(3), 240–250. https://doi.org/10.1056/NEJMoa2206297

Ministry of Health. (2011). Gender Reassignment Health Services for Trans People within New Zealand (p. 55). https://drive.google.com/file/d/1IMbkUyRQANq9Jp8l1DGm2fuTKVHN5Rc8/view?usp=sharing

NHS England. (2026). NHS England » Clinical policy: Prescribing of masculinising and feminising hormones for children and adolescents who have gender incongruence or dysphoria – public consultation guide. https://www.england.nhs.uk/long-read/clinical-policy-prescribing-of-masculinising-and-feminising-hormones-for-children-and-adolescents-who-have-gender-incongruence-or-dysphoria-public-consultation-guide/

Oliphant, J., Veale, J., Macdonald, J., Carroll, R., Johnson, R., Harte, M., Stephenson, C., Bullock, J., Cole, David, & Manning, Patrick. (2018). Guidelines for gender affirming healthcare for gender diverse and transgender children, young people and adults in Aotearoa, New Zealand. Transgender Health Research Lab, University of Waikato.

Spencer, B. (2025, April 6). NHS swaps gender drugs for ‘holistic’ care. The Sunday Times. https://archive.ph/EqgSQ

Staphorsius, A. S., Kreukels, B. P. C., Cohen-Kettenis, P. T., Veltman, D. J., Burke, S. M., Schagen, S. E. E., Wouters, F. M., Delemarre-van De Waal, H. A., & Bakker, J. (2015). Puberty suppression and executive functioning: An fMRI-study in adolescents with gender dysphoria. Psychoneuroendocrinology, 56, 190–199. https://doi.org/10.1016/j.psyneuen.2015.03.007

Taylor, J., Mitchell, A., Hall, R., Heathcote, C., Langton, T., Fraser, L., & Hewitt, C. E. (2024). Interventions to suppress puberty in adolescents experiencing gender dysphoria or incongruence: A systematic review. Archives of Disease in Childhood, 109(Suppl 2), s33–s47. https://doi.org/10.1136/archdischild-2023-326669

UK Parliament. (2025). Written questions and answers—Written questions, answers and statements—UK Parliament. https://questions-statements.parliament.uk/written-questions/detail/2025-03-18/39059

Veale, J. (2025, November 21). Puberty blockers: Why politicians overriding doctors sets a dangerous precedent. The Conversation. https://doi.org/10.64628/AA.ujspvseta

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