Depressive symptoms more common among sexual minority youth than heterosexual youth at age 10, develop faster during adolescence, and continue into young adulthood, but start to decline from age 18.
Young people who identify as sexual minorities--including those who identify as lesbian, gay, bisexual, not exclusively heterosexual, or not sure of their sexual orientation--consistently experience more symptoms of depression and report more self-harm than heterosexual youths throughout their school years and into early adulthood, according to an observational study which followed almost 5,000 young people from 10 to 21 years of age in the UK, published in The Lancet Child & Adolescent Health journal.
Previous research found that annually between 2001 and 2014, on average across 10- to 19-year-olds in the UK, around 37 per 10,000 girls and 12 per 10,000 boys were treated for self-harm .
The findings suggest that sexual minority youth and are four times more likely to report recent self-harm at ages 16 and 21 years than their heterosexual peers, and are at higher risk of depressive symptoms from as young as 10 years old.
"It is very concerning that despite changes in public perceptions and attitudes, sexual-minority youth remain at increased risk of long-term mental health problems," says Dr Gemma Lewis from University College London, UK, who led the research. "Our findings underscore the importance of mental health problems before conscious self-identification and labelling of sexual-minority orientation. It is imperative that we find new ways to reach these adolescents and that they are able to access high-quality support services from a young age." 
Recent estimates suggest that around 1 in 25 people aged 16-24 years in the UK identify as lesbian, gay, or bisexual . Previous studies have consistently shown that young people who identify as sexual minorities are more likely than their heterosexual peers to become depressed, self-harm, and attempt suicide. However, little research has looked at when increased risk for these mental-health problems emerges and how it develops over time.
In this study, researchers analysed data on 4,843 adolescents born between April 1991 and December 1992 from the UK Avon Longitudinal Study of Parents and Children (ALSPAC) who reported their sexual orientation at aged 16 years . The majority (87%; 4,203/4,843) of participants identified as heterosexual, and (13%; 625/4,843) as sexual minorities. Just over half of participants 53% were female. Depressive symptoms were assessed seven times between the ages of 10 and 21 years using a questionnaire. Additionally, a self-harm questionnaire was completed at ages 16 and 21 years.
Modelling was used to compare depressive symptoms and self-harm in sexual minority youth and heterosexual youth from early adolescence through to young adulthood after adjusting for other factors such as sex, age, maternal education, and social class.
Depressive symptoms were more common among sexual minority youth than heterosexual youth at age 10, developed faster during adolescence, and continued into young adulthood. From age 18, depressive symptoms started to decline, and more so in sexual minority youth (figure). The authors suggest that this decline could be the result of social and psychological changes such as increased independence or changes in peer groups.
Results also showed that sexual minorities were four times more likely to report self-harm in the previous year at both aged 16 and 21 years . Moreover, sexual minority youth were more than four times as likely to report previous self-harm with suicidal intent at age 21 than their heterosexual peers . Previous research found that annually between 2001 and 2014, on average across 10- to 19-year-olds in the UK, around 37 per 10,000 girls and 12 per 10,000 boys were treated for self-harm .
The authors note that the study is observational, so no firm conclusions can be drawn about cause and effect, but they speculate that the poorer mental health reported by sexual minorities may in part be due to the potentially hostile and stressful social environments created by the stigma, prejudice, and discrimination they face.
"The lack of sexual-minority role models and unquestioning acceptance of rigid concepts of gendered behaviour should be challenged in schools and society at large. We also need to ensure that doctors and those working in mental health are aware of this inequality and recognise the needs of sexual minorities," says Dr Lewis. 
The authors also point to several limitations, including that that the study is limited by its use of one dataset from one UK region, therefore the findings might not be generalisable to other populations. They also note that they did not examine mental health outcomes for different sexual-minority groups. Furthermore, the study only measured sexual orientation at one time point and may not have captured changes which could lead to subsequent mental-health problems. Lastly, the study could not distinguish between those who attempted suicide without a history of self-harm from those who had a history of both self-harm and attempted suicide.
Commenting on the implications of the study, Dr Rohan Borschmann from the Murdoch Children's Research Institute, Melbourne, Melbourne, Australia notes: "... the findings highlight the urgent need for policy makers, public health researchers, health-care professionals, and educators to join forces to address the underlying causes of this inequity and reduce the burden of disease on vulnerable young people."
He adds: "Irrespective of the exact nature of the relationship between sexual orientation and mental health, sexual-minority young people with mental health problems might experience double stigmatisation and it is well-established that discrimination and stigma are associated with decreased health outcomes. Reducing stigma and discrimination could, therefore, provide a pathway to primary prevention of mental disorders, by reducing the burden of disease, improving public health, and reducing health inequities. Further, programmes to prevent suicide and self-harm are often applied either to the general population--most of which is not at risk--or to those who have already self-harmed or attempted suicide. Tailoring self-harm prevention programmes to sexual-minority young people presents an alternative prevention strategy that warrants further attention."
Peer-reviewed / Observational study / People
NOTES TO EDITORS
This study was funded by Medical Research Council, Wellcome Trust. It was conducted by researchers from University College London, King's College London, and University of Bristol.
 Quotes direct from author and cannot be found in text of Article
 For the purposes of the analysis, the researchers defined sexual minorities as those who identify as lesbian, gay, bisexual, not exclusively heterosexual, or unsure of their sexual orientation.
 Crude estimates of self-harm risk in sexual minorities compared to heterosexuals were 22% (88/394) vs 9% (223/2537) at age 16 years and 15% (47/314) vs 5% (107/2104) at age 21 years. The four times risk estimate is calculated from the statistical model that is adjusted for other variables.
 Crude estimates of previous self-harm with suicidal intent at age 21 in sexual minorities compared to heterosexuals peers were 14% (41/288) vs 4% (85/1934). The four times risk estimate is calculated from the statistical model that is adjusted for other variables.
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