Adverse childhood experiences and mental health problems in a nationally representative study of heterosexual, homosexual and bisexual Danes

Non-heterosexual persons more often report adverse childhood experiences (ACEs) than heterosexuals, and they generally bear a greater burden of mental health challenges. However, population-based data on this topic are scarce. In a nationally representative study within the Project SEXUS, one of the world's largest cohort studies on sexual health, we used data from 57,479 individuals in Denmark to explore the interplay between ACEs and mental health problems among self-identified heterosexual, homosexual and bisexual persons, and among self-identified heterosexuals with or without same-sex sexual experience. Compared to heterosexuals, non-heterosexual persons were more likely to report most of the studied ACEs, with odds ratios (ORs) for the ACE category "abuse" ranging from 1.38 to 1.75 for homosexual women, from 1.76 to 2.65 for homosexual men, from 2.52 to 3.64 for bisexual women, and from 1.58 to 6.07 for bisexual men. Furthermore, non-heterosexual persons had consistently and statistically significantly higher odds for mental health problems (ORs: 1.50 to 4.63). Combinations of ACEs with a non-heterosexual identity resulted in markedly elevated odds for mental health problems, particularly among bisexual individuals. This included high odds for suicidal thoughts/attempts among bisexual persons with a history of "neglect" (women: OR=12.82; men: OR=35.24) and "abuse" (women: OR=11.81; men: OR=11.65). Among self-identified heterosexuals, combinations of ACEs with same-sex sexual experience were associated with consistently elevated odds for mental health problems (ORs: 2.22 to 12.04). The greater burden of ACEs among self-identified homosexuals and, most notably, bisexuals may account for part of their excess risk of mental health problems. These findings emphasize the public health importance of preventive measures to minimize the burden of ACEs and avert their harmful long-term effects. Moreover, they highlight the need to safeguard the welfare of children and adolescents with non-conforming expressions of sexuality.