Strang et al, 2015Transgender Youth Executive Functioning: Relationships with Anxiety Symptoms, Autism Spectrum Disorder, and Gender-Affirming Medical Treatment Status.
The study measured Executive Functioning (EF) in 124 gender dysphoric youth aged 11-21 and conducted a retrospective review. EF is a set of cognitive skills that enable top-down behavioural control. The researchers hypothesise that a) the social complexities and demands of navigating relationships while identifying as transgender, b) self-advocating for opposite-sex imitation treatment, c) associated conditions such as autism, and d) the treatments themselves will affect EF.
131 participants were enrolled in study from Washington, DC and Columbus, Ohio in the years 2018-2020. Participants were recruited from a range of intake services: some from psychosocial support services, some from medical only services, and some from mixed services. 124 of the 131 completed full reports. All participants desired some form of opposite-sex imitation treatments. Unfortunately, the study does not report the numbers receiving puberty blockers or cross-sex hormones (CSH) though these were variables of interest.
The researchers predicted that CSH treatment would reduce anxiety and subsequently reduce the burden on EF.
For puberty blockers however, the researchers were more equivocal.
The study used parent-reported BRIEF scores to measure EF, and CASI-5 for psychiatric symptoms, as well as reviewing medical histories.
Given the potential simultaneous: (1) benefits of pubertal suppression on mental health…(2) possible direct effects of gender-affirming care in reducing cognitive interference/load…, and (3) hypothetical direct neurodevelopmental impacts of pubertal suppression (e.g., disrupting gonadal-signaled neurodevelopment during a possible sensitive neurodevelopmental period…, we did not expect to observe the same level of positive relationship with executive functioning as hypothesized for [CSH]
EF problems were common. Anxiety and autism were the strongest predictors of EF problems. CSH treatment predicted fewer EF problems. Puberty suppression of greater than 1 year duration predicted more EF problems. Participants treated with CSH and/or puberty blocking did not have improved mental health compared to non-treated participants. This result suggests a direct effect on EF rather than an effect mediated by reduced anxiety.
Discussing the association between of longer duration puberty blockers and poorer EF, the researchers posit that puberty suppression has impaired brain maturation:
Endogenous gonadal hormones during puberty have been linked to maturation of cognitive and emotional control at both the behavioral and neural levels…It is possible that more extended pubertal interruption (i.e., longer-duration puberty blockers) might disrupt this process…
However the study is uncontrolled, and there are several potential confounds.
Reduced EF and no improvement in mental health in participants treated with blockers compared to non-treated participants is not a result that inspires confidence. The study’s design does not allow strong conclusions to be drawn.