The interaction of adverse childhood experiences, sex, and transgender identity as risk factors for depression: disparities in transgender adults.

Introduction: The intersectionality of sexism, transphobia, and adverse childhood experiences (ACE) on the mental health of transgender adults is poorly understood. We assessed whether the known association between ACE and depression was modified (or differed) by adult transgender identity and by assigned sex at birth, which we used as a proxy for adults' biological (e.g., hormonal changes) and social (e.g., sexism) experiences in childhood.

Methods: Data from a representative sample of 519 transgender and 127,214 cisgender US adults was retrieved from the 2019 and 2020 Behavioral Risk Factor Surveillance System surveys. The sample was stratified by assigned sex at birth. Adjusted, sample-weighted Poisson regressions and relative excess risk due to interaction (RERI) were used to assess whether transgender identity modified the association between ACE and depression within strata of assigned sex at birth.

Results: We found 42.4% of transgender compared to 24.9% of cisgender adults experienced 3+ ACE. The association between ACE and depression was stronger for transgender compared to cisgender adults, regardless of assigned sex at birth. However, transgender adults assigned female at birth with 1-2 ACE had a combined risk of depression that was higher than would be expected from the sum of the two risks alone (RERI test of interaction for transgender with 1-2 ACE vs. cisgender with zero ACE: 1.91 [95% confidence interval 0.47-3.36]; p = 0.009). The tests of interaction were not statistically significant (p > 0.05) for those assigned male at birth.

Discussion: Transgender adults may benefit more from depression interventions informed by and addressing childhood trauma than their cisgender counterparts, particularly for transgender adults who were assigned female at birth. Our findings suggest a need for greater and improved data collection of gender, experiences associated with assigned sex at birth, and ACE as these relate to the transgender community. This will allow for a better understanding of the intersecting influences of sexism, transphobia, and ACE on adult depression and for identifying particularly vulnerable sub-populations in need of support.