Summary

This was the UK's own test of puberty blockers, run by the Tavistock's gender clinic for children from 2011. Forty-four carefully chosen 12–15-year-olds were given a blocker drug and followed until they were over 16. The blockers paused puberty as intended. But there was no measurable change in emotional distress, self-harm, quality of life or gender distress, and bone density fell behind other teens their age. Most young people spoke positively about the treatment in interviews, and 43 of 44 went on to cross-sex hormones. The authors call for larger studies. There was no comparison group, numbers fell sharply after the first year, and a later re-analysis found up to a third got worse. So the study offers no evidence that blockers help mental health.

Key findings

• 44 名 12–15 歲（25 人出生時為男性、19 人出生時為女性）、有嚴重且長期性別困擾的年輕人，在門診通常經過兩年評估後，於 2011 至 2015 年間開始使用青春期阻斷劑。
• 無論家長還是年輕人，都沒有回報在 1、2 或 3 年後情緒或行為問題或自傷有任何改變。
• 生活品質、對身體的感受、性別困擾，以及應對得如何（由臨床人員判斷）也幾乎沒有改變；作者指出，阻斷劑不會使身體朝向期望的性別改變。
• 下背部的骨質密度成長比其他青少年慢，因此以他們的年齡來看落後，身高的成長也變慢。
• 頭痛、潮熱和疲倦等預期的副作用很常見；38% 在 15–24 個月後的訪談中表示精力不足。
• 44 人中有 43 人（98%）接續使用跨性別荷爾蒙，與荷蘭的發現相符，也就是幾乎沒有人在使用阻斷劑後停止。
• 2 年時資料中只剩 24 名年輕人，3 年時剩 14 人（3 年時只有 6 人填寫了自己的問卷），因此對較長期的影響幾乎無法說什麼。
• McPherson 和 Freedman 在 2024 年對同一批資料的重新分析發現，依衡量方式、時間點和回報者的不同，有 15–34% 的年輕人明顯變差。

Abstract

BACKGROUND: In adolescents with severe and persistent gender dysphoria (GD), gonadotropin releasing hormone analogues (GnRHa) are used from early/middle puberty with the aim of delaying irreversible and unwanted pubertal body changes. Evidence of outcomes of pubertal suppression in GD is limited. METHODS: We undertook an uncontrolled prospective observational study of GnRHa as monotherapy in 44 12-15 year olds with persistent and severe GD. Prespecified analyses were limited to key outcomes: bone mineral content (BMC) and bone mineral density (BMD); Child Behaviour CheckList (CBCL) total t-score; Youth Self-Report (YSR) total t-score; CBCL and YSR self-harm indices; at 12, 24 and 36 months. Semistructured interviews were conducted on GnRHa. RESULTS: 44 patients had data at 12 months follow-up, 24 at 24 months and 14 at 36 months. All had normal karyotype and endocrinology consistent with birth-registered sex. All achieved suppression of gonadotropins by 6 months. At the end of the study one ceased GnRHa and 43 (98%) elected to start cross-sex hormones. There was no change from baseline in spine BMD at 12 months nor in hip BMD at 24 and 36 months, but at 24 months lumbar spine BMC and BMD were higher than at baseline (BMC +6.0 (95% CI: 4.0, 7.9); BMD +0.05 (0.03, 0.07)). There were no changes from baseline to 12 or 24 months in CBCL or YSR total t-scores or for CBCL or YSR self-harm indices, nor for CBCL total t-score or self-harm index at 36 months. Most participants reported positive or a mixture of positive and negative life changes on GnRHa. Anticipated adverse events were common. CONCLUSIONS: Overall patient experience of changes on GnRHa treatment was positive. We identified no changes in psychological function. Changes in BMD were consistent with suppression of growth. Larger and longer-term prospective studies using a range of designs are needed to more fully quantify the benefits and harms of pubertal suppression in GD.

Conclusion

Treatment with GnRHa was efficacious in suppressing pubertal progression; anticipated effects of sex-hormone withdrawal were common and there were no unexpected adverse events. BMD increased in the lumbar spine and was stable at the hip, while BMD z-scores fell, consistent with delayed puberty. Overall participant experience was positive, but the authors identified no changes in psychological function, quality of life or degree of gender dysphoria. The great majority went on to cross-sex hormones; one did not, which the authors took as evidence that gender identity development continues on GnRHa. Larger, longer-term studies using a range of designs are needed to quantify benefits and harms.