Apparent autistic traits in transgender people: a prospective study of the impact of gender-affirming hormonal treatment

Purpose: We evaluated differences in Autism Spectrum Quotient (AQ) scores between a sample of hormone-naïve transgender and cisgender people and the impact of gender-affirming hormonal treatment (GAHT) on AQ scores across time. Furthermore, we assessed alexithymia and social anxiety as possible mediators of changes in AQ scores. Methods: A cross-sectional comparison between cisgender and transgender people before GAHT and a prospective study on the effects of GAHT over time were performed. Transgender and cisgender people completed several psychometric tests. A total sample of 789 persons (n = 229 cismen; n = 172 ciswomen; n = 206 transmen; n = 182 transwomen) referring to the Florence and Rome Gender Clinics between 2018 and 2020 was enrolled. Of these, 62 participants referring to the Florence Gender Clinic were evaluated in a prospective study at baseline and 12 months after GAHT. Results: Groups showed significant differences in terms of autistic traits: ciswomen showed lower scores of AQ, while cismen reported higher scores of AQ than all other groups. Transgender individuals showed significant higher levels of Gender Dysphoria (GD), body uneasiness, alexithymia and social anxiety, compared to cisgender ones. No significant differences in general psychopathology were found between groups. Across time, transmen and transwomen showed a significant reduction in AQ scores. The decrease in alexithymia and social anxiety after GAHT did not predict the change in AQ scores. Conclusions: The autistic traits in our sample may represent an epiphenomenon of GD rather than being part of an Autism Spectrum Disorder (ASD) condition, since they significantly decreased after 12 months of GAHT.