Understanding Differences in Mental Health for LGBTQ+ Adolescents

LGBTQ+ adolescents have higher rates of mental health problems and reduced wellbeing compared to non-LGBTQ+ adolescents (where LGBTQ+ is used an an umbrella term for all those with diverse gender identities or sexual orientations). This thesis aimed to understand whether these disparities are increasing over time, and possible differences in causal mechanisms behind them using a representative UK cohort.

A systematic review was carried out to assess whether trends in mental health differ for LGBTQ+ and non-LGBTQ+ adolescents over time. The outcomes of interest were measures of wellbeing, anxiety, depression, self harm or suicidality. Database searches found 2753 studies (1939 after removal of duplicates), 53 of which were potentially relevant after title and abstract screening and were screened using their full text. This resulted in 15 studies which met the criteria for inclusion. The review found that LGBTQ+ groups had poorer rates for all included outcomes across the studies compared to the non-LGBTQ+ groups. Anxiety and depression showed a statistically significant widening of disparities over time for those with diverse sexualities compared to heterosexuals, while there was no consensus for self harm, suicidality or wellbeing. Only 2 studies included analyses for those with diverse gender identities, and though they found elevated rates for all reported outcomes, they did not find any significant differences in trends compared to the cisgender groups which was likely due to the small sample sizes. The lack of findings in those with diverse genders highlights an urgent need for more data from this population to reduce the current blind spots, and aid in policy development.

This thesis explores how the relationships between factors related to mental health differ for LGBTQ+ and non-LGBTQ+ adolescents using data from the Millennium Cohort Study (MCS), a nationally representative UK cohort study following children born in 2000-2002 in England, Scotland, Wales and Northern Ireland. We analysed data from this study split into LGBTQ+ and non-LGBTQ+ groups to see if and how the relationship between determinants of mental health outcomes differ for the two groups. Outcome variables were self-harm and suicide attempts from responses provided at age 17. The determinants included demographics, and variables describing experiences, behaviours, and social environments provided both at ages 14 and 17, to explore the interaction of variables between time points. The analysis utilised a Bayesian Network (BN) approach with Directed Acyclic Graphs (DAGs) to estimate the likely direction of conditional dependencies between the variables and assess possible causal mechanisms. Hypothesis testing was performed to determine if the DAGs for the two groups were statistically significantly different. The intention to estimate causal relationships required several assumptions, including no unobserved confounding variables, and faithfulness. While these assumptions limit the certainty of causal claims and require caution in interpretation of results, steps were taken to mitigate these limitations, such as integrating domain knowledge and sampling from likely structures.

At age 17, 9612 of 10757 cohort members provided responses about their sexuality and gender identity. 2645 of 9612 were identified as LGBTQ+ and 6967 of 9612 were identified as non-LGBTQ+. Compared to the non-LGBTQ+ group, the LGBTQ+ group had higher rates for the outcome variables (42.50% vs 17.31% for self-harm, 16.07% vs 4.37% for suicide attempts), and higher rates of victimisation (68.50% vs 52.64% at age 17) and lower rates of high self-esteem (52.27 % vs 75.07% at age 17), both identified as key variables for both groups. The structures for the two groups were found to be significantly different (p¡0.001), and inspection of the DAGs showed some key differences. In particular, peer problems and substance use were more important for the LGBTQ+ group, and emotional symptoms and conduct problems were more important to the non-LGBTQ+ group.

The relationships found for the two groups were also used to explore downstream causal effects of interventions on the factors included in the structures. This analysis found that factors such as victimisation and self esteem had significant effects on self harm and suicide attempts for both the LGBTQ+ group and the non-LGBTQ+ group, while conduct problems and emotional symptoms were only significant for the non-LGBTQ+ group and substance use and peer problems were only significant for the LGBTQ+ group. These findings underscore the importance of tailoring interventions using insights on group specific mechanisms and designing policies that address the unique experiences of LGBTQ+ adolescents.

This thesis provides robust evidence of the persistence of mental health disparities experienced by LGBTQ+ adolescents, identifying key drivers and demonstrating the potential unintended consequences of well meaning interventions. Therefore, policy makers should implement targeted interventions, such as anti-bullying programmes, and ensure that policies consider the effects on LGBTQ+ adolescents specifically to avoid inadvertently widening inequalities. Consistent and inclusive data collection is also vital to validate the results in this thesis and to inform future policy decisions. Future research should aim to evaluate the long term effect of policies to guide evidence based strategies to effectively address the mental health inequities faced by LGBTQ+ adolescents.