Updated - 12 April 2021
No high quality, long-term studies on the psychological impacts of suppressing normal puberty exist. When studies include controls, they show no significant benefits from blockers and highlight a risk of permanent negative impacts on cognitive function, and worsening body image (particularly in females). Other studies lack controls and include psychosocial support in the treatment protocol. This means we cannot attribute the results to blockers.
Five of the intervention studies examining the psychological effects of blocking puberty in adolescents with gender dysphoria come from Vrije Universiteit in Amsterdam and the ACOG cohort. Another two studies (Costa et al., 2015 and Carmichael et al., 2021) are from the Gender Identity Development Service (GIDS) at the Tavistock and Portman Trust in London and the Early Intervention Study (EIS) cohort.
Results published in academic journals can reflect publication bias. It is sometimes necessary to look into the "grey" literature to gain a complete picture. Unpublished interim results from the EIS are included for this reason (Carmichael, 2015; Biggs, 2000).
|Controlled||n||P||cognitive||body image||self-harm||mental health|
|Costa et al., 2015||35||SB||~|
|Burke et al., 2016||21||BT||?|
|Staphorsius et al., 2015||20||B||~ ↓|
|Uncontrolled||n||P||cognitive||body image||self-harm||mental health|
|Carmichael et al., 2021||44||SB||~||~||~|
|Achille et al., 2020||47||SB||~||~ ↑|
|Miesen et al., 2020||178||SB||↓||↑|
|Carmichael, 2015||44||SB||↑↓||↑||~ ↓|
|Vries et al., 2014||55||SB||~ ↓||↑|
|Vries et al., 2011||70||SB||~ ↓||↑|
|Hough et al., 2017||25||B||~ ↓|
|Schneider et al., 2017||1||B||↓|
The tables above summarise the results of these studies.
The second column "n" refers to the number of treated participants who completed the study.
The "P" column is the treatment protocol: "B" - only blockers, "SB" - the participants were given psychosocial support and puberty blockers . "BT" - blockers and testosterone.
The results are classified four areas: "cognitive" - impacts of cognitive function, "body image", "self-harm", and "mental health" - measures of mental health other than the three aforementioned categories.
Arrows indicate the increase "↑" or decrease "↓" in the outcome measure. Arrows have been colour-coded red or blue to indicate a negative or beneficial change, respectively. A "~" indicates no significant changes (versus a control if the study has one). A "?" indicates a potential effect that goes unexplained by the study text.
It is difficult to justify the use of blockers for treating gender dysphoria. Blockers potentially expose a vulnerable child to unacceptable risks without proven benefit. Without an overview of all of the literature, including unpublished results, animal, and case studies, it would be possible to cherry-pick a subset of studies and claim that blockers are beneficial.
The literature is also analysed by Biggs (2020), Chew et al. (2018), and the National Institute for Health and Care Excellence (2020).