Carmichael et al, 2021

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#


Open Access


The researchers follow 44 gender dysphoric (GD) adolescents (24 male and 19 female) treated with puberty blockers and given psychosocial support at the Gender Identity Development Service (GIDS) in the UK. They measure bone density, mental health, self-harm behaviour, and reported life changes at baseline, 12, 24 and 36 months. Subjects could progress to cross-sex hormones soon after age 16 so only 24 remained on blockers after 2 years, and only 14 at 3 years.

The study is the followup to the initial results reported in Carmichael (2015).

Errors and controversy#

The research team were defendents in a High Court's judicial review of GIDS and released the study preprint on December 1st, 2020 the same day the High Court handed down the Bell Judgement. The defendants claimed to be unable to release the results during the review proceedings.

The study reports that the review by Chew et al (2018) "included data on the physical and mental health outcomes ofpubertal suppression using GnRHa in over 500 young people". However, an analysis of the citations reveals that the quoted 500 figure double-counts some study subjects reported in different studies. The true figure is closer to 300 (Cederblom, 2021).

Mental health#

Baseline mental health scores were non-clinical and there was no significant change in mental health outcomes. Measures included the parental questionnaire Child Behaviour Checklist (CBCL) and the Youth Self Report.

An odd aspect of recent clinical practice of puberty suppression and its research literature is that clinicians do not expect blockers to lessen the child's distress with their body. Earlier literature, in contrast, hypothesises that blockers would reduce GD (justifying the drastic intervention) (Viner, 2010; De Vries, 2011?; Biggs, 2021; Carmichael 2015). Instead, clinicians propose that puberty suppression will lessen their future potential dysphoria that the child may have as an adult who has committed to further opposite sex imitation. This puts the the practice of puberty suppression on uncertain ground. The practice is experimental, but the benefits are hypothetical and difficult to operationalise. In any case, GD did not improve druing the followup period.

Suicidal behaviour#

The study reports median and interquartile self-harm scores from the CBCL. CBCL scores can be 0 (no harm or not true), 1 (somewhat or sometimes true), or 2 (very true or often true). The median self-harm score is always 0 at baseline and in the followup intervals. The upper-quertile is always 1 except at the the 12 month interval when it is 2, and 0 at 36 months for the YSR. The median of a 0-2 score is a coarse measure, so its not suprising that there were no significant changes during followup.

However, an upper quartile score of 2 at 24 months implies that 10 or more out of 39 subjects reported that they "very often" harmed themselves. Given the seriousness of this result it is odd that the researchers did not report the self harm score as a frequency, or break out the results by sex as Carmichael (2015) does for the interim unpublished results on the same cohort. In the intermim results, "a significant increase was found in the first item “I deliberately try to hurt or kill self...especially natal girls”. Reporting an increase in suicidal behaviour in children under their care would not have been beneficial to the GIDS defense in the judicial review.

Bone Health#

During childhood and especially puberty Bone Mineral Density (BMD) increases until peak bone mass is reached in early adulthood (Boot et al, 1997).

Blocking puberty halts adolescent BMD accrual.