A majority of children treated with puberty blockers reported feeling happier after treatment started, a study found.

Research involving 44 young people aged 12-15 with persistent and sever gender dysphoria found that 43 (98%) chose to start cross-sex hormones at the end of the trial while one young person opted to continue with puberty consistent with their birth-registered sex.

Young people who along with their families were actively seeking treatment were invited to take part in the study, between 2011 and 2014, after being assessed for two years.

All were said to be experiencing gender dysphoria which had been consistent and persistent over at least 5 years and had significantly increased with the onset of puberty, with a high likelihood of severe psychological distress on facing full pubertal development.

The participants attended the Gender Identity Development Service (GIDS) at the Tavistock and Portman NHS Foundation Trust where they were assessed and received psychological support.

They were referred to University College London Hospitals NHS Foundation Trust for physical evaluation and treatment.

The study found that overall patient experience of changes on gonadotropin releasing hormone analogues (GnRHa) treatment (commonly called ‘puberty blockers’) was positive and there were no unexpected adverse events.

Those expected adverse effects reported (headaches, flushes, fatigue, etc) were mainly mild. 

The study identified little change in psychological functioning, but the experience of treatment as reported in interviews was positive for most.

The majority reported feeling happier and having better relationships with family and peers once treatment had begun.

However, some reported negative changes, which were largely related to anticipated side effects.

The study authors said the fact that 43 out of 44 of them went on to access gender-affirming hormones is consistent with other studies internationally where this rate varies, but is typically in the 2-5% range. 

However, one young person did stop treatment without progressing to cross-sex hormones which they said provides some evidence that development of gender identity continues on GnRHa treatment.

As anticipated, pubertal suppression reduced growth affecting both height and bone mass density.

In both cases (height and bone strength) there was some growth but less than would be expected during those years without hormonal suppression.

There was no loss of bone density over the study period and the expectation is that the resumption of growth on both counts would be achieved when puberty resumed either naturally or via cross-sex hormones administered from 16. 

The researchers said larger and longer-term prospective studies using a range of designs are needed to more fully quantify the benefits and limitations of pubertal suppression for those experiencing gender dysphoria.

Dr Polly Carmichael, Director of GIDS, said: “This paper adds to our understanding of the best way to support these young people.

"The results show patient experience on the blocker is positive overall and there were no unexpected adverse events, but that more research is needed around this complex issue.”

Professor Russell Viner, Professor of Adolescent Health at UCL (University College London), added: “At all stages of the process we have followed rigorous ethical guidelines.

"We have published findings in an open access international peer-reviewed journal with open peer review."

The paper, ‘Short-term outcomes of pubertal suppression in a selected cohort of 12 to 15 year old young people with persistent gender dysphoria in the UK’ is published in PLOS ONE.