Just adding this Sally Baxendale paper from February 2024 on neuropsychological function that may be of interest.
https://onlinelibrary.wiley.com/doi/10.1111/apa.17150
The impact of suppressing puberty on neuropsychological function: A review
Aim
Concerns have been raised regarding the impact of medications that interrupt puberty, given the magnitude and complexity of changes that occur in brain function and structure during this sensitive window of neurodevelopment. This review examines the literature on the impact of pubertal suppression on cognitive and behavioural function in animals and humans.
Methods
All studies reporting cognitive impacts of treatment with GnRH agonists/antagonists for pubertal suppression in animals or humans were sought via a systematic search strategy across the PubMed, Embase, Web of Science and PsycINFO databases.
Results
Sixteen studies were identified. In mammals, the neuropsychological impacts of puberty blockers are complex and often sex specific (n = 11 studies). There is no evidence that cognitive effects are fully reversible following discontinuation of treatment. No human studies have systematically explored the impact of these treatments on neuropsychological function with an adequate baseline and follow-up. There is some evidence of a detrimental impact of pubertal suppression on IQ in children.
Conclusion
Critical questions remain unanswered regarding the nature, extent and permanence of any arrested development of cognitive function associated with puberty blockers. The impact of puberal suppression on measures of neuropsychological function is an urgent research priority.
Relating to the claim that there is ‘some evidence’ of a detrimental impact on IQ of children, she says this about puberty blockers with precocious puberty.
In the only human study that established a baseline prior to treatment, Mul et al.43 examined the response to treatment with puberty blockers on a number of psychosocial outcomes including the Child Behaviour Checklist and performance on the shortened version of the Wechsler Intelligence Scales for Children in a group of 25 girls treated for early puberty. Three years after treatment commenced, the group as a whole had experienced a loss in both performance IQ and full scale IQ, with a decline of 7 points in the latter. While statistically significant at p < 0.01, the authors state that the decrease in IQ was not ‘clinically relevant’, a conclusion repeated in a later citation of the study.44 While the average loss of IQ points was 7, it is noteworthy that at least one patient in this study experienced a significant loss of 15 points or more, since the highest IQ score in the group was 138 at baseline and this dropped to 123 following treatment.
And this about the use for Gender dysphoria.
Three studies were identified that examined the neuropsychological impact of GnRH analogue treatments in transgender and gender diverse young people. In a single case study, Schneider et al. (2017) examined the impact of pubertal suppression on brain white matter and (white matter fractional anisotropy) and cognitive function (Wechsler Intelligence Scale for Children-IV) in an 11-year-old treated for gender dysphoria (male to -female). On admission, at the age of 11 years and 10 months, the patient was assessed to have a global IQ of 80. Treatment with GnRHa was instigated at age 11 years, 11 months. The patient was reassessed age 13 and 3 months, at which time, a loss of 9 IQ points had occurred, and the IQ had dropped to 71. A loss of 15 points was evident in working memory. At 14 years and 2 months, a loss of 10 global IQ points and 9 points in working memory remained apparent. The verbal comprehension index (a measure which depends on the expansion of vocabulary and conceptual thinking in adolescence, for the standardised score to remain stable) deteriorated progressively over the follow-up, falling from the initial baseline of 101, to 91 (age 13) and 86 (age 14), a loss of 15 points over 3 years.