Mental health, social adversity & health-related outcomes in sexual minority adolescents: findings from a contemporary national cohort study

Background Sexual minority adolescents are more likely to have mental health problems, adverse social environments, and negative health outcomes compared with their heterosexual counterparts. There is a paucity of up-to-date population-level estimates of the extent of risk across these domains in the UK. We analysed outcomes across mental health, social environment, and health-related domains in sexual minority adolescents compared with their heterosexual counterparts in a large, contemporary national cohort. Methods The Millennium Cohort Study (MCS) is a birth cohort study in the UK following up children born between Sept 1, 2000, and Jan 11, 2002 across England, Wales, Scotland, and Northern Ireland. Children recruited from the MCS have been followed up over six recruitment sweeps to date at ages 9 months, 3 years, 5 years, 7 years, 11 years, and 14 years. We analysed mental health, social, and health-related outcomes in sexual minority versus heterosexual adolescents at age 14 years. Additionally, we estimated the accumulation of multiple adverse outcomes in both groups. The primary aim of the study was to assess whether sexual minority adolescents experienced more adverse outcomes than heterosexual adolescents. Findings Between January, 2015, and April, 2016, 9885 adolescents provided a response about their sexual attraction. 629 (6%) of 9885 adolescents (481 female participants and 148 male participants) were identified as sexual minorities. 9256 (94%) of 9885 participants (4431 female and 4825 male) were attracted to the opposite sex or not attracted to the same sex and identified as heterosexual. Sexual minority adolescents were more likely to experience high depressive symptoms (odds ratio [OR] 5·43, 95% CI 4·32–6·83; p<0·0001), self-harm (5·80, 4·55–7·41; p<0·0001), lower life satisfaction (3·66, 2·92–4·58; p<0·0001), lower self-esteem (β 1·83, 95% CI 1·47–2·19; p<0·0001), and all forms of bullying and victimisation. Sexual minorities were more likely to have tried alcohol (OR 1·85, 95% CI 1·47–2·33; p<0·0001), smoking (2·41, 1·92 −3·03; p<0·0001), and cannabis (3·22, 2·24–4·61; p<0·0001), and also had increased odds of being less physically active (β 0·36, 95% CI 0·25–0·46; p<0·0001), perceiving themselves as overweight (OR 1·73, 95% CI 1·40–2·14; p<0·0001), and dieting to lose weight (1·98, 1·58–2·48; p<0·0001). Sexual minority adolescents had more co-occurring mental health outcomes (mean 1·43 of 3 outcomes, 95% CI 1·34–1·52) compared with heterosexual adolescents (0·40 of 3 outcomes, 0·38–0·41), and more total cumulative difficulties (mean 9·43 of 28 outcomes, 95% CI 9·09–9·76 in sexual minority adolescents vs 6·16 of 28 outcomes, 6·08–6·23 in heterosexual adolescents). Interpretation Sexual minority adolescents in the UK experience disparities in mental health, social, and health-related outcomes despite living in a time of substantial progress in rights for sexual minorities. These adverse outcomes co-occur, with implications for lifelong health and social outcomes. Health and educational practitioners should be aware of the increased risk for adverse outcomes in sexual minority adolescents.