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Tavistock's Gender Identity Development Service (GIDS) is England's only NHS specialist gender clinic for children

By Hannah Barnes

BBC Newsnight

The majority of children in a landmark study on puberty blockers experienced positive or negative changes in their mental health, new analysis suggests.

The original study of 44 children, who all took the controversial drugs for a year or more, found no mental health impact - neither benefits nor harm.

But a re-analysis of that data now suggests 34% saw their mental health deteriorate, while 29% improved.

The authors of the original report have welcomed the new evidence.

The re-analysis, which has been seen by BBC Newsnight, questions some of the conclusions from the 2021 study about the potential mental health impact of puberty blockers on under 16s. It also sheds some light on this much-debated, but little understood, area of children's medicine.

The new study has not been in a peer-reviewed journal yet. The authors say they felt there was an urgency in getting the information into the public domain.