Follow-up study: outcomes after hormones and surgery

In autumn 2014, the Amsterdam research group led by child psychiatrist Annelou de Vries published a follow-up study on the Dutch Protocol in the journal Pediatrics. It is the study most frequently cited worldwide as evidence for treating young people.

What the study showed

The study described 55 young adults who had received puberty blockers as teenagers, followed by sex hormones and finally surgery. They were assessed at least one year after surgery. Their gender dysphoria had disappeared, and their psychological well-being was comparable to that of their peers.

The criticism

The group was small and strictly selected: only young people with dysphoria dating back to early childhood, without serious psychological problems and with parental support. There was no control group, and the follow-up took place soon after surgery. Of the seventy participants in the 2011 study, fifteen were missing; one of them had died from complications following surgery. A British replication at the Tavistock clinic found no improvement in psychological well-being. In 2023, the weekly magazine The Economist summarised these objections; see the archive entry on that article.

How the research was designed

The researchers took measurements three times: before the start of puberty blockers, at the start of sex hormones and at least one year after surgery. At those assessments, the participants were on average almost fourteen, almost seventeen and almost twenty-one years old. The group consisted of 22 transgender women and 33 transgender men. In addition to questionnaires about psychological symptoms and gender dysphoria, the researchers looked at education, employment, living arrangements and life satisfaction. None of the participants reported regretting the treatment; what is known about regret in the longer term is discussed in the figures on detransition.

Measuring gender dysphoria

A frequently cited objection concerns the questionnaire used to measure gender dysphoria. It has one version for boys and another for girls. Before treatment, participants completed the version corresponding to their sex at birth; after treatment, they completed the version for the opposite sex. According to critics, including American psychiatrist Stephen Levine, this switch almost inevitably leads to a lower score, regardless of how the participant actually feels. The Amsterdam researchers consider the switch logical, arguing that otherwise the questions would no longer correspond to the participant’s situation.

Those who were missing

Fifteen of the seventy young people from the first study did not take part. Some had undergone surgery less than a year earlier, some did not want to participate or did not respond, and a few could not undergo surgery for medical reasons. One participant died from an infection shortly after surgery.

Later Dutch research

In 2022, the Amsterdam group published data on 720 young people who had started puberty blockers between 1972 and 2018. Of these, 98 percent went on to take sex hormones. The researchers see this as confirmation that the diagnosis is made carefully. Critics interpret the same figure as an indication that blockers are not a pause, but the beginning of a pathway that is rarely discontinued.

Significance

To date, no other clinic has followed a group of young people from the start of puberty blockers through to after surgery and published its findings. This makes the study unique and explains why both supporters and critics repeatedly refer back to it.

The study was cited in guidelines and by clinics in other countries. Since around 2014, however, mainly teenagers have been presenting whose dysphoria began only at puberty, often alongside additional psychological problems. Whether the outcomes also apply to them is a key question in the current debate; see also Littman’s article.