Updated - 4 October 2020
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, increased suicidal behaviour, and worsening body image (particularly in females). Two lower quality studies on the same cohort show improved mental health, we cannot attribute results to blockers due to the lack of controls and inclusion of psychosocial support in the treatment protocol.
There are six published intervention studies examining the psychological effects of blocking puberty in adolescents with gender dysphoria. Five of these studies come from Vrije Universiteit in Amsterdam and the ACOG cohort. Another study (Costa et al., 2015) is from the Gender Identity Development Service (GIDS) at the Tavistock and Portman Trust in London and the Early Intervention Study 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 Unpublished results from the GIDS board report are included for this reason (Carmichael, 2015; Biggs, 2000).
|Intervention Study||n||P||C||cognitive||body image||self-harm||MH|
|van der Miesen et al., 2020||178||SB||N||↓||↑|
|Carmichael, 2015||44||SB||N||↑↓||↑||~ ↓|
|Costa et al., 2015||35||SB||Y||~|
|Burke et al., 2016||21||BT||Y||?|
|Staphorsius et al., 2015||20||B||Y||~ ↓|
|Vries et al., 2014||55||SB||N||~ ↓||↑|
|Vries et al., 2011||70||SB||N||~ ↓||↑|
|Hough et al., 2017||25||B||Y||~ ↓|
|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 . "B + T" - blockers and testosterone.
"C" identifies whether the study used a control group (Yes / No).
The results are classified four areas: "cognitive" - impacts of cognitive function, "body image", "self-harm", and "MH" - 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 the 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 with no 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.